Sandrine Fréguin-Gresh

Valérie Angeon

How public policies and social capital secure professional insertion and livelihoods? Insights from Haitian migrant farm workers in Guadeloupe

Keywords: vulnerability-resilience, migration, sustainable rural livelihood, capabilities, agriculture Résumé

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

individuels qui sont contraints par la structure sociale qui se décline à différentes échelles. L'article aborde la capacité des migrants à organiser leur vie et à faire face aux aléas. L'analyse s'appuie sur une enquête qualitative menée auprès de migrants haïtiens. Deux résultats majeurs sont mis en évidence. Premièrement, les migrants mobilisent, accumulent et font circuler des capitaux dans un espace transnational afin de poursuivre leurs stratégies de subsistance. Deuxièmement, certaines ressources (régularisation, accès à la terre et aux activités non agricoles) interfèrent dans leurs trajectoires et remettent en question leur résilience/vulnérabilité. Les résultats discutent en particulier du rôle spécifique du capital social et des politiques publiques dans la sécurisation des revenus, un débat qui peut être utile en termes d'action publique pour soutenir les migrants dans le renforcement de leurs moyens de subsistance.

Mots-clés : vulnérabilité-résilience, migration, moyen d'existence durable, capabilités, agriculture

Resumen

Este artículo tiene como objetivo comprender las trayectorias de medios de vida de los migrantes haitianos que trabajan en la agricultura en Guadalupe como jornaleros o pequeñas granjas. Cuestiona los mecanismos que intervienen en los procesos de construcción de su resiliencia/vulnerabilidad. El marco teórico propuesto articula el enfoque de medios de vida sostenibles con un enfoque en términos de "capacidades circulatorias-transformadoras" inspirado en el trabajo de Sen. Al analizar la dotación de capitales y recursos, asi como las opciones y las trayectorias socioeconómicas, el artículo cuestiona el margen de maniobra de los migrantes para lograr el modo de vida al que aspiran. La reflexión otorga entonces un rol central a las elecciones individuales que están limitadas por la estructura social en diferentes niveles. El artículo analiza la capacidad de los migrantes para organizar sus vidas y hacer frente a los peligros. El análisis se basa en una encuesta cualitativa realizada entre migrantes haitianos. Se destacan dos resultados. En primer lugar, los migrantes movilizan, acumulan y circulan capitales en un espacio transnacional para implementar sus estrategias de subsistencia. En segundo lugar, ciertos recursos (regularización, acceso a la tierra y actividades no agropecuarias) interfieren en sus trayectorias y cuestionan su resiliencia/vulnerabilidad. Los resultados permiten discutir en particular el rol específico del capital social y de las políticas públicas en la generación de ingresos, un debate que puede ser útil en términos de acción pública para apoyar a los migrantes en el fortalecimiento de sus medios de vida.

Introduction

Guadeloupe, as a French outermost region, has long been a destination for the emigrating Caribbean peoples, especially from Haiti. Haitian born persons are the first group of residing immigrants in Guadeloupe (about 30,000 persons in 2020, following the UN Department of Economic and Social Affairs, Population Division). Haitians mostly work in low-skilled jobs in Guadeloupe, particularly in the construction sector as building workers and agriculture as farmwaged laborers or, in some cases, as self-employed small-scale farmers. The socio-economic integration, living and working conditions of these immigrants working in agriculture in Guadeloupe can be difficult and unstable.

The article proposes an original analytical framework to better understanding livelihood trajectories of Haitian migrant farm workers in Guadeloupe. Those migrants, endowed with unequal resources, develop more or less sustainable livelihood strategies linked to agriculture. The paper then analyzes the life stories of two generations of Haitian migrants who are farm waged earners and small-scale farmers. The survey reveals how their different resources' endowment and choices may or may not allow sustainable livelihoods. The paper aims at answering the following question: what are the processes that allow Haitian migrant farm workers in Guadeloupe to secure (or not) their livelihoods and increase their resilience?

The proposed framework articulates the Sustainable Rural Livelihoods approach (Chambers and Conway, 1991) with capabilities [START_REF] Ingrid | The Capability Approach, Routledge Companion to Political Philosophy[END_REF][START_REF] Armatya | Development as freedom[END_REF]. It gives a central place to the capacity of individuals to access, activate, transform, accumulate and circulate resources (i.e. "circulatorytransformative capabilities") that enable Haitian immigrants to be and develop livelihood strategies in more or less constraining contexts. The analytical framework makes it possible to link the weight of choices, constraints and opportunities at different levels that shape decision making, with the capacity for action and reaction of migrants. Based on a qualitative survey conducted among 46 agricultural waged-earners and small-scale farmers of Haitian origin in Guadeloupe and key informants, the results shed light on the processes of evolution of the degree of resilience/vulnerability of those immigrants. Qualitative data, which are seldom used to assess capitals and resources, constitute core elements to understand the process of establishing sustainable livelihood pathways. They allow understanding livelihood in a holistic way.

The paper unfolds in three steps. A first section provides a brief description of the context that shapes individuals' livelihood trajectories and capabilities. A second section presents synthetically the framework that emerged from an inductive approach, grounded in empirical evidences. A third section analyzes and discusses the results of the survey, focusing on the mechanisms of mobilization, accumulation, and circulation of capitals and resources of the Haitian migrants. The results then question the capacity of the different livelihood strategies to reinforce Haitian migrants' resilience or vulnerability.

I/ Embedding Haitian migrants' livelihood trajectories in historical, political and macro-social structures

Guadeloupe has long been subject to strong migratory flows of migrants, especially from other Caribbean countries [START_REF] Cédric | La diaspora haïtienne : vers l'émergence d'un territoire de la dispersion ?[END_REF][START_REF] Cédric | L'intégration des Antillais en France et aux Etats-Unis : contextes socioinstitutionnels et processus de territorialisation[END_REF]. The migration pressure has accentuated in the last decades, along the increasing differences in living standards between countries [START_REF] Michel | La Guadeloupe et la Martinique dans l'histoire française des migrations en régions de 1848 à nos jours[END_REF]. The national office of statistics of France estimates the foreign population in Guadeloupe at about 19 500 persons (INSEE, 2017), a number probably underestimated since some of them are in an irregular situation. More realistic, some authors estimate that Haitian migrants might account for more than 30,000 persons in Guadeloupe (UN Population Prospects).

As other foreign populations, Haitians migrants mainly access low-skilled jobs in Guadeloupe, in particular in agriculture [START_REF] Cédric | La diaspora haïtienne. Territoires migratoires et réseaux[END_REF]. Generally, Haitian migrants work as farm laborers. While one generally recognizes that working conditions in agriculture are difficult (arduous work, large working hours, low daily hourly rate etc.), in Guadeloupe and elsewhere, Haitian migrants often accept those working conditions, both as farm workers and small-scale farmers. The political, economic and social context in Haiti, characterized by instability, violence and insecurity [START_REF] Van Vliet Geert | Une étude exhaustive et stratégique du secteur agricole/rural haïtien et des investissements publics requis pour son développement[END_REF], had contributed to make them accept difficult working conditions. In addition, some of them manage to settle as small-scale farmers, renting land or even buying land to produce diversified crops for local markets.

Agriculture was once a leading economic sector in Guadeloupe. In the last decades, it has sharply declined decreasing number of farms, ageing farmers, dropping contribution to the GDP. However, it still plays a significant role in exports1 (Agreste Guadeloupe, 2022), and more broadly in rural dynamics (social cohesion, landscape conservation) and job creation in a context where the unemployment rate exceeds 30% (three times the average of France) (INSEE, 2020).

Nowadays, agriculture in Guadeloupe is dominated by a small number of large-scale farms (4% of the total, contributing to 46% of the value of the production in 2019) that are specialized in export crops (Agreste Guadeloupe, 2022). Those large-scale farms are generally formal and operate with a great number of farm-waged workers, among which Haitian born peoples. Aside those farms, numerous small-scale (or even very small) farms exist. Small-scale farms are not always formal and administratively recognized (some of them are even managed by illegal foreign peoples, among which Haitians). However, small-scale farms play a significant role in local food systems [START_REF] Sandrine | Les petites agricultures familiales en Guadeloupe : une contribution à l'ancrage de l'alimentation ?[END_REF], even if they have been historically marginalized and excluded from public supports. They also contribute to maintain activity in rural areas as they mainly operate using family workforce, but also occasionally, employing farm-waged workers, among which Haitian peoples.

Another important characteristic of agriculture in Guadeloupe is that the sector benefit from a large set of public supports, among which some are enacted at the European level and others at the national and local scales. One of the most significant is the Program of options specifically relating to remoteness and insularity (POSEI), which supports agricultural production through direct payments to farmers. Evidences show that large-scale export agriculture is the main recipient of the POSEI with about 70% of the value of supports [START_REF] Marzin | Étude sur les nouveaux modèles agricoles des départements d'Outremer[END_REF]. Thus, public supports in agriculture then contribute to maintaining farm waged-work in Guadeloupe, which benefit to migrants' job creation. In addition, even if many of the numerous small-scale farmers, among which the Haitian migrants that settled as farmers, are not eligible to these programs, some of them manage to be beneficiaries and can consolidate their livelihoods, considerably reducing the risks associated with agriculture.

At least, in addition to productive programs, other public policies have important effects in terms of access to employment, and of providing supports and assistance for Haitian migrants.

First, the migration policies in France play a significant role for Haitian migrants. French migration policies have significantly conditioned the trajectories of migrants. Lendaro (2013: 8) summed up their evolution as follows: "Until the 1980s, migrants were still perceived as individuals passing through, whose legitimacy to reside on the territory was temporary. The crisis of the early 1970' and the irruption of mass unemployment provided European governments with the justification to officially stop economic migration from 1974 onwards, implying the redefinition of tools for managing the migrant workforce".

The 1990' then marked a turning point due to the difficult socio-economic situation and the increase in mass unemployment, as well as the growing precariousness of working conditions. Migration policies in France have become stricter and sought to select the candidates for immigration according to the needs of the national labor market, linking in addition the validity of the residence permit to the duration of the work contract. Flows were then constrained by higher controls. Consequently, migration policies play a central role in the conditions of travel and entry into the national territory, and provide a broader framework for the living conditions of Haitian migrants when they arrive in Guadeloupe.

Second, Guadeloupe implements number of social programs and aid schemes. Haitian migrants may access social supports in various domains, particularly if they are in a regular situation, but also for some of them, when they are political refugees: health (access and coverage of care), housing, professional activity and its interruption (minimum income, unemployment insurance, retirement) among the major ones. It is well known that social programs help to secure livelihoods for those who manage to access them.

Consequently, Haitian migrants engaged in the agricultural sector in Guadeloupe can benefit from the combined effects of that policy mix, according to their individual situation. Although the conditions of access to policies are diverse, the main trend is the following. Those who enter into Guadeloupe illegally, who mostly work as farm-waged workers in both large-scale farms and small farms, have little access to any kind of public support (neither social or productive programs). Those who enter legally, working as farm laborers, may access some social assistance programs. Those who settle as small farmers barely access productive public policies in agriculture. In all cases, individuals are unequal in accessing public supports, which therefore reinforces the socioeconomic differentiation and reveals the discriminating role of public policies.

The framework of constraints and opportunities previously described shaped by the macro-social, economic and political contexts in which settle Haitian migrants once arriving in Guadeloupe. That context offers a sphere of possibilities in which those migrants make decisions and take actions to develop a livelihood to lead the life that they find valuable. From there, the choice, stemming from the individual freedoms, allows individuals to engage in a possible livelihood trajectory. That set of constraints and opportunities constitutes one of the core elements of the proposed analytical framework.

II/ Grasping resilience/vulnerability through livelihood trajectories and capabilities

Migration is an important livelihood strategy worldwide that has been widely studied [START_REF] Bryceson | African Rural Labour, Income Diversification and Livelihood Approaches: A long-term Development Perspective[END_REF][START_REF] Geneviève | Partir pour rester. Survie et mutations des sociétés paysannes andines (Bolivie)[END_REF][START_REF] De Haan | Exploring the Frontier of Livelihoods[END_REF][START_REF] Dick | Multi-spatial livelihoods in Sub-saharan Africa: Rural Farming by urban households -the case of Nakuru Town, Kenya[END_REF]. In particular, work in agriculture for migrants is particularly relevant [START_REF] Michalon | Les migrations internationales au coeur de l'agriculture et de l'agroalimentaire industriels[END_REF]. We mobilize the Sustainable Rural Livelihoods (SRL) framework to analyze trajectories of Haitian residing migrants in terms of socio-professional insertion in the agricultural sector in Guadeloupe.

Based on the pioneer research of [START_REF] Robert | Sustainable rural Livelihoods: practical concepts for the 21st century[END_REF], largely supplemented by others [START_REF] Franck | Rural Livelihood Diversity in Developing Countries: Evidence and Policy Implications[END_REF][START_REF] Scoones | Sustainable rural livelihoods: a framework for analysis[END_REF], the concept of livelihood can be defined as follows: "A livelihood comprises the capabilities, assets (including both material and social resources) and activities required for a means of living. A livelihood is sustainable when it can cope with and recover from stresses and shocks, maintain or enhance its capabilities and assets, while not undermining the natural resource base" (Scoones, 1998: 5). As in this definition, the paper mobilizes the capability approach [START_REF] Martha | Capabilities as Fundamental Entitlements: Sen and Social Justice[END_REF][START_REF] Ingrid | The Capability Approach, Routledge Companion to Political Philosophy[END_REF][START_REF] Armatya | Development as freedom[END_REF]) that aims at addressing various concerns: (i) individuals are different in their abilities to convert the same resources into valuable functionings ('beings' and 'doings'). (ii) Individuals are bale to internalize harshness of contexts. They consider the sphere of possibilities at a given point in the trajectory; and (iii) whether or not individuals take up the options they have, they evaluate actual achievements ('functionings' or livelihood strategy) and effective freedom ('capability').

Such an approach leads to focus not only on the outcomes of livelihood strategies, but to question the way a person, in specific contexts, is able (or not) to pursue his or her ultimate ends. It also considers the outcomes of livelihoods in terms of resilience/vulnerability and not only sustainability as such. The literature defines vulnerability as exposure to external or internal disturbances [START_REF] Gilberto | Linkages between vulnerability, resilience, and adaptive capacity[END_REF]. Vulnerability refers to the exposure to the risk of insecurity combined with a high degree of inability to find alternative strategies, while resilience deals with the ability to cope with adversity, shocks or stresses by withstanding, resisting, absorbing, recovering from, or successfully adapting to them [START_REF] Valérie | Reviewing Composite Vulnerability and Resilience Indexes: A Sustainable Approach and Application[END_REF]. Shocks refer to highintensity events, with an unpredictable level of disruption whose impact is immediate. Stresses refer to low-intensity, regular, predictable events whose effects are cumulative.

Mobilizing those guiding notions, our approach is grounded in the theoretical evolutions of the SRL framework in terms of livelihood trajectories [START_REF] De Haan | Exploring the Frontier of Livelihoods[END_REF][START_REF] Do Rego | Social Inclusion and Sustainable Livelihood: Trajectories of Portuguese Immigrants in Curaçao. From Contracted Oil Workers through Agro-Commercial Entrepreneurship to Business Elite[END_REF][START_REF] Susannah | Resilient or vulnerable livelihoods? Assessing livelihood dynamics and trajectories in rural Botswana[END_REF]. Approaching livelihood trajectories allows analyzing socioeconomic differentiation following risk perceptions (de Haan, 1999: 43), which aims at considering the outcomes of livelihoods in terms of resilience/vulnerability.

To unravel livelihoods, we mobilize other core notions of the SRL framework (see Figure 1) such as capitals and resources. As per Bebbington (1999), we accept a wide conception of the resources that people need to access to develop a livelihood, which leads to consider livelihoods in terms of access to various types capitals (or assets). Accessing capitals is then having means through which individuals make a living, but also "give meaning to the persons' world" (ibid p2022). Then, capitals are the means of enhancing the existing ways in which resources (that are available or latent) contribute to livelihoods. However, as mentioned by Johnson (1997: 4) "Like resources, capitals can generate value and productivity for those who have it at their disposal. Its value, however, is defined in terms of its potential. Capital can be accumulated and transferred, but once it is used for a specific purpose, it becomes a resource. […] Social and natural capital, then, represent stocks of relationships and physical inputs which, when exploited, become resources".

The idea of accumulating social capital is compatible with the notion of circulation of resources, in particular those linked to migration (Baby-Colin et al., 2009;[START_REF] Laurent | Les territoires de la mobilité : migration et communautés transnationales entre le Mexique et les États-Unis[END_REF][START_REF] Mung Emmanuelle | La Circulation migratoire[END_REF]. Then, accumulation and circulation of capitals and resources occur within a spatial and temporal matrix that make it possible to set up livelihoods according to existing possibilities and individual choices. Such a conception of resources and capitals, of their modalities of activation and circulation reveals what we call "circulatory-transformative capabilities" of individuals. That does not mean that accumulation and circulation of capitals and resources take place without difficulties or tensions, in particular due to the costs of accessing capitals that can be high (and risky). Those difficulties or tensions strongly affect the sustainability of livelihoods. The proposed framework aims at describing a dynamic sequence from the decision-making to migrate to Guadeloupe and settle in that new context, up to the socio-economic insertion of Haitian migrants into the agricultural sector.

At first (before deciding to migrate), individuals are endowed with capitals that depend on the contexts in which they are. Contexts refer here to the historical and macro-social structures at origin in Haiti (social, economic, institutional and security conditions, and public policies). They also refer to migrants' specific meso and micro-social levels, in particular related to social capital. Social capital includes the relations with widen family and other networks at the origin in Haiti and in the transnational space. Those elements of the contexts constitute the transnational spaces of life and activities where individuals are able to take the decision to migrate, as part of their livelihoods [START_REF] Michelle | Éditorial[END_REF]. Thus, at this stage, migrants can potentially convert capitals into resources to pursuit a new socio-economic trajectory in migration. One should underline that the incentive to migrate implies assessment procedures, which are specific to individuals: two persons evolving in the same context will not make the same choices because they will not perceive risks and possibilities in the same way [START_REF] Massey | Social structure, household strategies, and the cumulative causation of migration[END_REF][START_REF] Étienne | Les théories des migrations. Synthèse de la prise de décision individuelle[END_REF]. The capacity to interpret the framework of constraints and opportunities shapes the spaces in which individuals live and work. The subjective dimension of choice is a component of individual freedom [START_REF] Armatya | Development as freedom[END_REF] in the sense that it allows the expression of decisions that determine future trajectories and livelihood strategies.

After deciding to migrate, individuals then are able to activate and transform capitals into resources, choosing what they want to be and do in that new sphere of possibilities (modes of expression of their overall freedoms) in new contexts. That process reveals their capacity to activate and transform their potentialities, which means, to mobilize their circulatory-transformative capabilities. Those capabilities lead to the creation of a new portfolio of activities and incomes in migration that may (or not) allows securing their livelihoods and thus being resilient or vulnerable.

The framework relies on a major hypothesis: contexts at different scales are not given, but evolve and are a social construction. In that sense, the different scales of contexts are interdependent. The contexts at origin and destination, and at the different scales, are a multiform social construction, from the furthest away from the individual (macro social) to the closest (microsocial) or intermediate (meso social) levels, these different scales being interdependent one with each other. The framework highlights the relationships that individuals maintain with contexts both at origin and destination, and at different scales: the micro and meso levels and at the macro level referring to the institutions and organizations within which they set up their strategies.

In line with other research studies (Demazière and Samuel, 2010), the framework considers the contextualization of the trajectories of migrants by paying attention to both individual lives and intermediate spaces (family, friendly and professional relational networks, institutions). This framework of constraints and opportunities offers the migrant a field of possibilities in which to make decisions and take action, translated into livelihoods. From there, the choice, stemming from the individual freedoms, allows them to engage in one or other of the possible trajectories. In particular, it focuses on the role of public policies that can be both a structuring framework and a source of shocks and stresses. The aim is therefore to decipher a temporal and spatial matrix of circulatory-transformative capabilities from which the construction of livelihood strategies takes place, and to explore how this matrix results in increasing resilience or vulnerability.

The proposed framework makes it compatible to both consider the processes of accumulation of capitals and the circulation of resources, that takes place within a social, spatial and temporal matrix and result in interactions between actors that make it possible to achieve individual functionings. Such a conception of resources and capitals, of their modalities of activation and their movement reveals the importance of the process of circulatory-transformative capabilities.

That dynamic sequence then explains the degree of resilience/vulnerability, as illustrated in the Figure 2. The case study of Haitian migrants in the agricultural sector in Guadeloupe is relevant to illustrate the framework proposed.

III/ Livelihood trajectories of two generations of Haitian migrants in the agricultural sector in Guadeloupe

To understand sustainable livelihood trajectories by considering resilience/vulnerability of Haitian migrants, the research sets up a qualitative survey in Guadeloupe from June 2019 to February 2020.

The empirical data collected for this study was based on interviews. We gathered data in open-air markets and in farms through semi-structured interview guides. The surveys targeted two groups of respondents. In an exploratory phase, we interviewed 11 key informants from the major migrant associations and agricultural unions and organizations, to provide useful information to shed light on migrants' capacities and potentialities at community level but also on the macrosocial structures, they face at destination in their working environment in Guadeloupe. After identifying the main open-air markets and agricultural regions where Haitian workers operate (strategic places), wethen conducted semi-structured interviews with 31 hired farm workers and farmers of Haitian origin who were randomly selected using a snowball sampling method. As farm laborers and farmers are mostly males, men mostly form the sample. Face-to-face interviews with migrants were helpful to gather information about their life stories and individual trajectories in Haiti before migrating and about their working life and situation since their arrival in Guadeloupe. For these interviews, we followed an interview guide centered on their employment status, their working conditions, the resources they mobilize for work, but also on their livelihood outcomes. The data collected is made up of discourses, narratives, life stories that explained Haitians' migration path in time and space. In addition to the fieldwork, we enriched our understanding of Haitian migration context by reading about the evolution of migration policy in France and the contemporary history of migration in Haiti.

The analysis thus relies on a rich empirical material that describe the individual trajectories and the contexts in which they take place (Table 1). This information is referenced with respect to the framework developed. The approach makes it possible to characterize and analyze the importance, according to the period of arrival of migrants, of the intermediate spaces and the historical and macro-social structures (in particular public policies) within which individuals evolve.

Table 1: Characteristics of the interviewed farm workers and farmers

Political regime in Haiti and related sociopolitical and economic situation

Political regime in France and related migratory policy

Gender

Age on first arrival

Curre nt age M ale

Fe mal e Mean Duvalier Dictatorship and the Post-dictaturial period of the military junta The" Gaullist" Republic with successive right-wing administrations 8 1 24 64 Socio-political insecurity and repressive system Immigration is characterised by family reunification, accompanied by a specific policy 2 0 30 68 Opening of the regime to leftwing administration (1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995) 1 0 26 59 The Aristide-Lavalassian period (1990)(1991)(1992)(1993)(1994) and the Military coup, followed by a US intervention (1994)(1995)(1996)(1997)(1998)(1999)(2000) Immigration becomes a political theme in the agenda and is adddressed by mass regularization campaigns 2 0 29 65 Instability and increasing pressure on the population (growing organized crime) Source: Authors.

Results allow a generalization process by questioning and verifying the suggested analytical framework through empirical observations. The robustness of the work relies on the phenomena and processes brought to light. We then pay attention to the regularities of the empirical analysis.

This section presents the results obtained from the survey. The approach makes it possible to characterize and analyze the role of certain elements of the contexts, and the role of capitals and resources endowment which importance varies according to the period of arrival of migrants.

III/ 1. Two profiles of migrants with differentiated capabilities depending on the arrival period

The results show a clear differentiation between the surveyed Haitian migrants in the agricultural sector following the period of their arrival in Guadeloupe. Those findings are in line with other studies in different contexts [START_REF] Do Rego | Social Inclusion and Sustainable Livelihood: Trajectories of Portuguese Immigrants in Curaçao. From Contracted Oil Workers through Agro-Commercial Entrepreneurship to Business Elite[END_REF][START_REF] Lendaro | Inégalités sur le marché du travail entre deux générations d'immigré-e-s. Ce que l'action publique fait aux parcours de vie[END_REF].

The majority of surveyed Haitian migrants that arrived in Guadeloupe until the 1980' were young (17-25 years old), single, low educated men from low-income families engaged in agriculture in Haiti. At that time, the weight of the historical and macro-social structures in Haiti also strongly contributes to their decision-making to migrate. Migrants considered their sphere of possibilities unsatisfactory in Haiti, in a context of lack of local job opportunities or because of political insecurity (time of the dictatorial regime of the Duvalier). All individuals of the sample mentioned those constraints. In addition, the political, economic and social conditions in Guadeloupe (migratory policy, abundance of low-skilled jobs) were also particularly favorable to host Haitian migrants. All the surveyed migrants until the 1980' mentioned arriving in Guadeloupe in a regular situation (buying a tourism visa, with minimum economic guarantees, traveling by plane) and having access to a job as agricultural workers in large-scale sugarcane or banana farms just a few days after their arrival. These benefits allowed migrants to maintain, if not create and improve their economic, human and physical resources. At that time, migrants decided to migrate to create a future for themselves (search of autonomy and emancipation, the main motivation for many of them), but also to help their family and relatives. Migration was thus the result of individual but also collective choices as family and the close social networks funded journeys and visas, as well as a minimum economic capital to settle in Guadeloupe. In return, migrants send remittances to the origin. The role of the family at origin is a common finding from most of transnational studies [START_REF] Véronique | Families, labor and farms[END_REF]Baby-Colin et al., 2009;[START_REF] Sandrine | Le système familial multi-localisé, un modèle d'analyse pour regarder autrement les ruralités au Suds[END_REF][START_REF] Alejando | La mondialisation par le bas. L'émergence des communautés internationales[END_REF]. The belief that one could quickly accumulate resources in Guadeloupe, nourished by migrants who have previously settled, was also important in their decision-making. The weight of their initial individual capitals' endowment was also important: all the interviewed migrants until the 1980' considered themselves as not the poorest before leaving Haiti. They were endowed with economic and physical capitals (such as land, houses, etc.) or had access to sufficient incomes to fund their travel to Guadeloupe. If the surveyed migrants of that period underlined the great diversity of the capitals mobilized to migrate, social and economic capitals were the most crucial.

From the 1990' and especially since the 2000', migration flows from Haiti to Guadeloupe intensified, as a corollary of recurrent external shocks (economic and political crisis, social unrest, natural hazards). Those migrations increased despite the reinforcement of migratory policies in France at the same time. Although dissuasive, the constraints of the macro-social structures in Guadeloupe did not significantly curb the influx of migrants. However, the macro-social structures in Haiti still weighted strongly on the decision making to migrate. Most of surveyed migrants that arrived in Guadeloupe from the 1990' onward had different motivations and capitals' endowments that the migrants of the first migratory wave. Those "new" migrants had a quite different profile: they were still young active peoples, but a little older (23-45 years old, 30 on average), and had often formed a family in Haiti. Some of them were women. If some of them had a previous working experience in agriculture, most abandoned school at the early stages or were not educated at all, had experiences in nonfarm, sometime informal activities in urban areas in Haiti. Second, while this second wave of migrants still mobilized their social capital to leave Haiti, and, while they also considered themselves as not the poorest, traveling to Guadeloupe was more expensive, challenging and risky. Their only option to migrate to Guadeloupe at that time, expect for those who already had a family there and could benefit from family reunification, was to arrive illegally. They travelled by boats, through different countries, in conditions that endangered their lives. In addition, costs of travels and the risk of deportation were higher. To finance that uncertain journey, migrants and their families and networks had to mobilize lot of economic resources (selling goods, borrowing within or outside family and friendship networks). The social capital mobilized at that time came from Haiti and Guadeloupe, but also from a wider transnational space.

III/ 2. The roles of social capital for all migrants in facilitating an integration marked by stigmatization, irregularity and harsh working conditions

For all the interviewed migrants, family and friends were the ones who generally welcomed them upon their arrival in Guadeloupe. These networks of people with migratory experience and circulatory-transformative capabilities (because they were already settled at destination) were a central support for the social and professional insertion of new migrants who, in turn, played the same welcoming and support roles for those who arrived after them [START_REF] Thomas | Transnationalization in international migration: implications for the study of citizenship and culture[END_REF][START_REF] Douglas | The social organization of Mexican migration to the United States[END_REF]. Social capital was not limited to their family members and friends, but included individuals met during the travels to Guadeloupe and in the wider Haitian community circles in Guadeloupe. Those networks relied on mutual aid and sharing, with what that implied in terms of transformation and circulation of resources [START_REF] Cédric | L'intégration des Antillais en France et aux Etats-Unis : contextes socioinstitutionnels et processus de territorialisation[END_REF]. However, networks could not always be the panacea: in some cases, family and friends could take advantage of the precariousness of the newcomers and committed abuses, sometimes violence, even sexual. Networks of Haitians in Guadeloupe worked as described by scholars working on transnationalism [START_REF] Laurent | Les territoires de la mobilité : migration et communautés transnationales entre le Mexique et les États-Unis[END_REF][START_REF] Eric | De la comunidad territorial al archipiélago familiar: Movilidad, contractualizacion de la relaciones intergeneracionales y desarrollo local en el sur del estado de Veracruz[END_REF][START_REF] Alberto | Social Capital and International Migration: A Test Using Information on Family Networks[END_REF] that enabled migrants to activate and transform resources to pursuit the livelihoods they chose after migration. Social capital was then central to capabilities as it conditioned the sphere of possibilities, articulating the places of departure, transit and destination.

According to interviews, Haitians in Guadeloupe were victims of anti-migrant attitudes (i.e. words and acts perceived as xenophobia towards their community), a phenomenon that was highly perceived by the migrants from the second wave of migration. Those felt more affected by those attitudes than migrants from other origins did. Stigmatization of Haitian migrants in Guadeloupe is a social phenomenon known and described in the literature [START_REF] Bougerol | Une rumeur à la Guadeloupe : de certaines pratiques supposées des haïtiens[END_REF][START_REF] Laënnec | Racisme et sous-produit du racisme : Immigrés haïtiens et dominicains en Guadeloupe[END_REF]. For Audebert (2012: 47), while the Haitian farm waged worker is both sought after for his low cost and the quality of his work, at the same time, he is seen as "a risk linked to fantasy, cultural and demographic perceptions whose translation is very real in the local political practices of managing this migration".

The status of Haitian migrants in Guadeloupe is a heterogeneous social fact, as evidenced in the interviews that showed the diversity of residence permits from which they could benefit. The notion of regularization is preferred to that of legality, as it is associated with obtaining residence permits that allow access to full residence in Guadeloupe and then, to social assistance (health, housing, minimum income...). Mostly all the surveyed migrants experienced a period of irregularity during their trajectory in Guadeloupe, even when they arrived legally (the case of most of the migrants from the first wave of migration) as their visa could have expired and not been renewed. Some migrants explained their situation as undocumented farm waged workers. The term "undocumented" avoids suggesting that all migrants in an irregular situation are clandestine (i.e. people unknown to the administrative services), with a legal situation alternating for several years between irregularity and regularity. Some surveyed migrants, especially those who entered irregularly after the 2010', can still be in that situation. However, and even irregular, most of the migrants found a job upon arrival as farm waged workers in export plantations. Sometimes, and even with an irregular status, they could access to declared jobs (with health care and access to other social programs). Migrants surveyed perceived irregularity as a rough condition, especially since it sometimes gave rise to hints of violence. This situation had obviously consequences in terms of precariousness, working conditions (arduous work with more worked hours, lower pays than regular workers, labor rules not respected, etc.), but also in accessing jobs (reduced mobility due to the fear of being caught and deported). Furthermore, it increased risk exposure, especially in the absence of health monitoring, while farm waged workers used potentially toxic agrochemicals in bananas' plantations (e.g. Chlordecone). However, regardless of abuses and risks, Haitian waged workers accepted the harshness of irregularity and of farm waged labor for a period after arriving in Guadeloupe. That resulted from a compromise between accessing to necessary incomes to live (and to send to their families in Haiti) and being in the expectative of a formal higher income-generating job and, ultimately, stable residence permits to capitalize more (and quicker) resources.

III/ 3. Bifurcation of Livelihood trajectories toward resilience/vulnerability: the roles of public policies and employment

All the surveyed migrants considered regularization determinant to capitalize on their initial endowments, as well as to access new resources and engage in chosen livelihoods. Most, but not all the surveyed migrants were regularized in time. However, regularization process was long and difficult due to administrative barriers and stigmatization. Nevertheless, there were differences between the two generations of migrants. Up to the 1980', the surveyed migrants could benefit from regularization campaigns at a time where few peoples were candidates to residence permits. One should note that previous work in agriculture also contributed to facilitate the regularization process, confirming the determinant role of employment [START_REF] Sébastien | Le travail de l'irrégularité. Les migrant•e•s sans papiers et l'économie morale de l'emploi[END_REF]. After the 1990', accessing to regularization was perilous, long and expensive. In all cases, social networks played a major role in the process. Migrants adopted diverse regularization strategies. Some migrants became permanent residents through marriage or after having children born in Guadeloupe. Others engaged in a hazardous process involving paid intermediaries to carry out the administrative procedures on their behalf. Others, especially those from the second generation, obtained the status of asylum seeker or political refugee. This status was harder to access after the mid 2000' because of the reinforcement of the conditions of admissibility [START_REF] Frédérique | L'immigration en France : concepts, contours et politiques, Espace, Populations[END_REF].

Once regularized, migrants could diversify their livelihoods thanks to the new capitals they could access (equipment, skills and experiences), which was also facilitated by networks and economic resources. That allowed them to engage in new jobs that they aspired to, as a mode of expression of their freedoms. Regularization also allowed improving working conditions and incomes of farmwaged workers who kept this activity. Finally, and that is surely the most important to consolidate livelihoods, regularization allowed accessing social programs. That issue has long been one of the most controversial topics in the French political debate. While irregular migrants could occasionally receive some kind of assistance (like free coverage of the medical care), regularized migrants could benefit from a wider range of social programs (minimum income, pension system, housing support, unemployment, disability, family support...). In all cases, social supports, working as safety network, enabled them to secure their income basis given the insufficiency and instability of farm wages. They also allowed to mitigate risks and sometimes to ensure an income provision when migrants had to stop working consequently of disability (consequence of years spent working hard as farm laborers) or in case of unemployment. However, some migrants, even regularized, may not have access to information and not make use of social programs.

Contrary to popular belief, Haitian migrants in Guadeloupe are not only farm-waged workers: the survey shows that Haitian migrants can also be small-scale farmers in a context of an ageing agricultural population and a growing disinterest of the youth in agriculture. Some of the migrants surveyed could access land. In many cases, access to land was in sharecropping after years working as a farm-waged worker for a "boss", owner of large-scale export farms that let them a small plot to crop. Sharecropping relies on a modality of access to land in return for the payment of an annuity proportional to the harvest or its value. In Guadeloupe, it refers to a mode of tenure usually derived from contracts related to farm wage earning. Once again, social capital played a key role for accessing land thanks to contacts and recommendations of other laborers and sometimes, of previous "bosses". Economic resources were also crucial and for that reason, securing incomes basis was determinant. If regularization was not necessary to access land in sharecropping, it was a prerequisite to access rental and ownership. Thus, only regularized migrants could establish a formal rental contract or a deed of ownership as they were linked to identity papers. However, in some cases, migrants, even regularized, faced barriers to access land because of anti-migrant attitudes. Migrants mentioned that becoming self-employed small-scale farmers, especially in rental and property, was an aspiration: even if the working conditions of farmers were also difficult and introduced risks related to agricultural production, they were better than those of farm-waged laborers were. However, the important thing, to them, was the freedoms to be and to do what they aspired to.

Conclusion

This paper analyses how Haitian migrants in Guadeloupe succeeded in overcoming their initial constraints of precariousness and vulnerability to build a new livelihood through farm waged labor and small scale farming. This case study illustrates how an immigrant category with few resources and capitals, manages to forge sustainable rural livelihoods pathways by successfully integrating the agricultural sector. As a result, some Haitians in Guadeloupe turned from marginalized and stigmatized workers into fully included farmers. Small-scale farms hosted Haitians, that hence contribute to the development of local agriculture.

The article shows that the matrix of the Haitians' circulatory-transformative capabilities is in constant evolution. It is the place for the conversion of certain capitals and the activation of resources which, once transformed, can accumulate and circulate in a transnational space of life and activity. The opportunities and constraints in this matrix are different according to the period of arrival in Guadeloupe. Migrants from before the 1990s, who arrived at a period when borders are relatively open and economic immigration is still promoted, integrate quite quickly into Guadeloupian society. While the first wave of migrants is generally excluded from agricultural support schemes for those who have gained access to land, like other small farmers in Guadeloupe, migrants are either integrated into the agricultural sector through their regularization or are declared salaried workers. Under these conditions, it is easier for them to accumulate resources (economic, human, natural and physical) permitted by their activation strategy and their social capital, after consolidating their income through social assistance. The migrants of the second wave remain in a more precarious situation: they can remain illegal and undeclared workers for a long time, sometimes with abusive working conditions. They are excluded from public policies, most of them (except for political refugees) from social assistance, which does not promote their integration.

The situation after the 1990s is a framework of constraints particularly weighing on the fate of the second wave of migrants. The tightening of migration policies generates uncertainty, insecurity, precariousness and risk-taking, which are key features of the current migration context in France. It affected the paths to professional integration and working conditions, which have become more difficult and precarious. For these two generations of migrants, the surveys highlight the central and permanent role of social capital, which is indispensable for the formation of circulatorytransformative capabilities and their subsequent mobilization. It is meta-capital, in the sense that it enables the activation of other capital and the multiplication of resources both in time and space (Guilmoto and Sandron, 2000;[START_REF] David | Network Effects and the Dynamics of Migration and Inequality: Theory and Evidence from Mexico[END_REF][START_REF] Alberto | Social Capital and International Migration: A Test Using Information on Family Networks[END_REF]. The notion of network is thus a key to understanding how migrants construct their trajectories [START_REF] Jacqueline | Social networks, gender, and immigrant incorporation : resources and constraints[END_REF].The article also underlines the decisive role of public policies at pivotal moments in the life of migrants: in the process of regularization, in access to social benefits and, to a lesser extent, to agricultural subsidies. However heavy this framework of constraints may be, the results insist on the room for maneuver of individuals and show that the number of people they have is not determined. Far from being passive, migrants are agents of their own trajectories [START_REF] Djaouida | Une lecture des migrations au prisme des savoirs et des ressources[END_REF].They thus demonstrate the constructed part of vulnerability-resilience.

Endowments evolves in time along livelihoods trajectory and their mobilization depends on individuals and collective choices, even if affected by contexts. Thus, opportunities and constraints are different according to individuals' evaluation of risks, but time and space matter.

The proposed analytical framework allows a generalization of the results, as it identifies two central elements: (i) the importance of the initial context at several scales and the capitals endowment it carries along, which can be converted, and activated, by migration; (ii) the differentiated potentialities and capacities of migrants to transform, multiply and circulate again the resources generated. In this process, the role of social capital and public policies is crucial.

For further developments, one should explore two lines of research. First, one should address the issues of socialization of the outcomes of livelihoods trajectories, and the legacy of the learning process between generations. That could thus question the existence of social determinism or bifurcations and their conditions of emergence. This field of study is approached by the literature on "segmented assimilation" (do Rego and de Bruijn 2017). That could also allow analyzing the perimeter of the temporal and spatial matrix of the circulatory-transformative capacities and the social contours of transnationality. Secondly, one could enrich the analytical framework to question how circulatory-transformative capabilities upscale and out scale at territorial levels. Since individual livelihoods fit in a transnational space, underlining the plurilocalized character of the matrix, conversion, activation and transformation or resources provoked by migration should have territorial effects.

Bibliographie

Agreste Guadeloupe (2022) Mémento de la statistique agricole.

Figure 1 :

 1 Figure 1: An adaptation of the Sustainable Rural Livelihoods framework

Figure 2 :

 2 Figure 2: Proposal for an integrative analysis framework

Raw and processed farm products account for about 30% of the total exports, among which a significant share comes from bananas and products from the sugar cane industry

ACKNOWLEDGMENTS

The research presented in this paper comes from the project 'Food governance and practices of agricultural households: an approach through food supply flows and family multi-location' (GAPRA), which was co-funded by the National Research Institute for Agriculture, Food and the Environment (INRAE) and the French Agricultural Research Centre for International Development (CIRAD) through the GloFood Metaprogram. The authors thank Olivier Crevoisier (University of


Keywords: molecularly imprinted polymer (MIP), conducting polymer (CP), biosensor, electrochemical sensor, disease biomarkers, Alzheimer's disease biomarker, Parkinson's disease biomarker, stress biomarker

Many diseases can be identified by the appearance of the markers in body fluids like blood, urine, saliva, tears, etc. This article aimed to summarize the newest studies about electrochemical sensors with molecularly imprinted polymers as sensitive and selective layers on the electrode to detect protein-based biomarkers of neurodegenerative diseases. The article describes the detection of the biomarkers of Alzheimer's disease (Amyloid-β oligomers and p-Tau), Parkinson's Disease (α-Synuclein), and stress biomarker (α-amylase) using molecular imprinting technology, and also, analyses the development of the sensor design, and the influence of used materials. The research methods, the application of different electrodes, the influence of the polymers, and the established detection limits are reviewed and compared.

Molecularly Imprinted Polymers for the Recognition of Biomarkers of certain Neurodegenerative Diseases

Greta Pilvenyte 1 , Vilma Ratautaite 1,2 *, Raimonda Boguzaite 1 , Urte Samukaite-Bubniene 1,2 , Deivis Plausinaitis 2 , Almira Ramanaviciene 3 , Mikhael Bechelany 4 , Arunas Ramanavicius 1,2 * ,

Introduction

The selectivity and sensitivity of some sensors can be improved by the application of various structures that increase the selectivity of these sensors [START_REF] Ramanavicius | Progress and Insights in the Application of MXenes as New 2D Nano-Materials Suitable for Biosensors and Biofuel Cell Design[END_REF][START_REF] Ramanavicius | Insights in the Application of Stoichiometric and Non-Stoichiometric Titanium Oxides for the Design of Sensors for the Determination of Gases and VOCs (TiO2-x and TinO2n-1 vs. TiO2)[END_REF][START_REF] Naseri | Recent Progress in the Development of Conducting Polymer-Based Nanocomposites for Electrochemical Biosensors Applications: A Mini-Review[END_REF]. The semiconducting properties of some conducting polymers (CPs) are very suitable for sensing purposes, therefore, structures based on conducting polymers can be applied in various sensing devices [START_REF] Ramanavicius | Conducting Polymers in the Design of Biosensors and Biofuel Cells[END_REF][START_REF] Chen | Recent advances in molecular imprinting technology: current status, challenges and highlighted applications[END_REF][START_REF] Lakard | Electrochemical Biosensors Based on Conducting Polymers: A Review[END_REF]. Some conducting polymer formation technologies enable to increase in the selectivity of sensors toward selected analytes [START_REF] Ramanavicius | Conducting Polymers in the Design of Biosensors and Biofuel Cells[END_REF][START_REF] Emir | Amperometric nonenzymatic glucose biosensor based on graphite rod electrode modified by Ni-nanoparticle/polypyrrole composite[END_REF][START_REF] Ratautaite | Characterization of caffeine-imprinted polypyrrole by a quartz crystal microbalance and electrochemical impedance spectroscopy[END_REF][START_REF] Holguín | Molecular dynamics of the interaction of l-tryptophan with polypyrrole oligomers[END_REF][START_REF] Kumar | Advances in electrospun nanofiber fabrication for polyaniline (PANI)-based chemoresistive sensors for gaseous ammonia[END_REF][START_REF] Tekbaşoğlu | Enhancing biosensor properties of conducting polymers via copolymerization: Synthesis of EDOT-substituted bis(2pyridylimino)isoindolato-palladium complex and electrochemical sensing of glucose by its copolymerized film[END_REF]. CPs possess remarkable semiconducting properties [START_REF] Pontes | Poly(vinylidene fluoride-cohexafluorpropylene)/polyaniline conductive blends: Effect of the mixing procedure on the electrical properties and electromagnetic interference shielding effectiveness[END_REF][START_REF] Samukaite-Bubniene | Towards supercapacitors: Cyclic voltammetry and fast Fourier transform electrochemical impedance spectroscopy based evaluation of polypyrrole electrochemically deposited on the pencil graphite electrode[END_REF][START_REF] Zhao | Chloride ion-doped polyaniline/carbon nanotube nanocomposite materials as new cathodes for chloride ion battery[END_REF][START_REF] Wang | Urchinlike Ni1/3Co2/3(CO3)0.5OH•0.11H2O anchoring on polypyrrole nanotubes for supercapacitor electrodes[END_REF], and can be deposited over the signal transducer [START_REF] Ratautaite | Electrochemical stability and repulsion of polypyrrole film[END_REF][START_REF] Iroh | Corrosion performance of polypyrrole coating applied to low carbon steel by an electrochemical process[END_REF]. Polymer-based structures can be exploited for charge transfer from the redox enzymes [START_REF] Oztekin | Direct electron transfer from glucose oxidase immobilized on polyphenanthroline-modified glassy carbon electrode[END_REF]. Different polymer formation approaches are applied for the formation of CPs-based sensing structures, these methods include chemical [START_REF] Leonavicius | Polymerization Model for Hydrogen Peroxide Initiated Synthesis of Polypyrrole Nanoparticles[END_REF], electrochemical [START_REF] Samukaite-Bubniene | Towards supercapacitors: Cyclic voltammetry and fast Fourier transform electrochemical impedance spectroscopy based evaluation of polypyrrole electrochemically deposited on the pencil graphite electrode[END_REF], enzymatic [START_REF] Felix | Electrochemical immunosensors -A powerful tool for analytical applications[END_REF], and/or microorganism-assisted [21][START_REF] Apetrei | Modification of Aspergillus niger by conducting polymer, Polypyrrole, and the evaluation of electrochemical properties of modified cells[END_REF][START_REF] Apetrei | Cell-assisted synthesis of conducting polymer -polypyrrole -for the improvement of electric charge transfer through fungal cell wall[END_REF] formation methods. During the formation of CPs some biomaterials (e.g.: enzymes [START_REF] Ramanavicius | Self-encapsulation of oxidases as a basic approach to tune the upper detection limit of amperometric biosensors[END_REF][START_REF] Lakard | Urea potentiometric enzymatic biosensor based on charged biopolymers and electrodeposited polyaniline[END_REF][START_REF] German | Glucose biosensor based on glucose oxidase and gold nanoparticles of different sizes covered by polypyrrole layer[END_REF], antigens [START_REF] Ramanavicius | Electrochemical formation of polypyrrole-based layer for immunosensor design[END_REF] antibodies [START_REF] Ramanavicius | Conducting Polymers in the Design of Biosensors and Biofuel Cells[END_REF][START_REF] Felix | Electrochemical immunosensors -A powerful tool for analytical applications[END_REF][START_REF] Ramanaviciene | Pulsed amperometric detection of DNA with an ssDNA/polypyrrole-modified electrode[END_REF] and various receptors), [START_REF] Plikusiene | Evaluation of affinity sensor response kinetics towards dimeric ligands linked with spacers of different rigidity: Immobilized recombinant granulocyte colony-stimulating factor based synthetic receptor binding with genetically engineered dimeric analyte derivatives[END_REF] which are able to bind selected targets and provide advanced selectivity for biosensor. However, the stability and the price of biomolecules are mostly not sufficient, therefore, some reasonable replacements are demanded to reduce the price and increase the stability of designed bioanalytical systems. A very reasonable alternative is the employment of molecularly imprinted polymers (MIPs) [START_REF] Ramanavicius | Advances in Molecularly Imprinted Polymers Based Affinity Sensors (Review)[END_REF][START_REF] Baleviciute | Evaluation of theophylline imprinted polypyrrole film[END_REF] here among many other polymers CPs can be very efficiently applied [START_REF] Ramanavicius | Advances in Molecularly Imprinted Polymers Based Affinity Sensors (Review)[END_REF][START_REF] Baleviciute | Evaluation of theophylline imprinted polypyrrole film[END_REF][START_REF] Sangiorgi | Molecularly imprinted polypyrrole counter electrode for gel-state dye-sensitized solar cells[END_REF][START_REF] Syritski | Environmental QCM sensors coated with polypyrrole[END_REF][START_REF] Rebelo | Molecularly imprinted polymer-based electrochemical sensors for environmental analysis[END_REF][START_REF] Ayerdurai | Molecularly imprinted polymer-based electrochemical sensors for food contaminants determination[END_REF][START_REF] Keçili | Chapter 12 -Imprinted Materials: From Green Chemistry to Sustainable Engineering[END_REF]. MIPs can be used in the development of analytical systems for the diagnosis of infectious [START_REF] Cui | Molecularly Imprinted Polymers and Surface Imprinted Polymers Based Electrochemical Biosensor for Infectious Diseases[END_REF] and some other diseases.

Recently, the diagnosis of some diseases is very often based on the determination of particular biomarkers. Moreover, biomarkers are essential for the rational development of drugs and medical technologies. Common and recurrent disorders such as cancer, neurological, and cardiovascular diseases are considered to be the leading causes of human death. Using biosensors, these disorders could be detected by biomarkers at an early stage of pathogenesis. To increase patient survival, rapid and targeted treatment is necessary. According to the National Cancer Institute, a biomarker is a biological molecule found in blood or other body fluids, or tissues that is a sign of a normal or abnormal process, or of a condition or disease. Such compounds also may be used for following the body's responses to a treatment of a disease or condition [38].

This study aims to overview MIPs for the determination of protein-based biomarkers for the diagnosis of some diseases.

Major principles and methodologies used for MIP formation

MIPs are formed by polymerizing functional monomers in the presence of an analyte to form cavities for target molecules and deposited on different types of electrode surfaces (pencil graphite electrode [START_REF] Ratautaite | Molecularly Imprinted Polypyrrole for DNA Determination[END_REF], graphite electrode [START_REF] Ratautaite | Electrochemical Sensors based on L-Tryptophan Molecularly Imprinted Polypyrrole and Polyaniline[END_REF], quartz crystal microbalance sensor [START_REF] Ratautaite | Characterization of caffeine-imprinted polypyrrole by a quartz crystal microbalance and electrochemical impedance spectroscopy[END_REF][START_REF] Plausinaitis | Quartz Crystal Microbalance-Based Evaluation of the Electrochemical Formation of an Aggregated Polypyrrole Particle-Based Layer[END_REF][START_REF] Plausinaitis | Evaluation of Electrochemical Quartz Crystal Microbalance Based Sensor Modified by Uric Acid-imprinted Polypyrrole[END_REF], surface plasmon resonance sensor [START_REF] Balciunas | Towards electrochemical surface plasmon resonance sensor based on the molecularly imprinted polypyrrole for glyphosate sensing[END_REF], boron-doped nanocrystalline Diamond [START_REF] Baleviciute | Evaluation of theophylline imprinted polypyrrole film[END_REF][START_REF] Ratautaite | Molecularly Imprinted Polypyrrole Based Impedimentric Sensor for Theophylline Determination[END_REF][START_REF] Ratautaite | Evaluation of Histamine Imprinted Polypyrrole Deposited on Boron Doped Nanocrystalline Diamond[END_REF], platinum electrode [START_REF] Ratautaite | Molecularly Imprinted Polypyrrole based Sensor for the Detection of SARS-CoV-2 Spike Glycoprotein[END_REF][START_REF] Ratautaite | Evaluation of the interaction between SARS-CoV-2 spike glycoproteins and the molecularly imprinted polypyrrole[END_REF], etc.). After analytes are removed, they leave complementary imprinted cavities to recognize target molecules such as low molecular weight molecules (e.g. theophylline [START_REF] Baleviciute | Evaluation of theophylline imprinted polypyrrole film[END_REF][START_REF] Ratautaite | Molecularly Imprinted Polypyrrole Based Impedimentric Sensor for Theophylline Determination[END_REF], caffeine [START_REF] Ratautaite | Characterization of caffeine-imprinted polypyrrole by a quartz crystal microbalance and electrochemical impedance spectroscopy[END_REF], histamine [START_REF] Ratautaite | Evaluation of Histamine Imprinted Polypyrrole Deposited on Boron Doped Nanocrystalline Diamond[END_REF], uric acid [START_REF] Plausinaitis | Evaluation of Electrochemical Quartz Crystal Microbalance Based Sensor Modified by Uric Acid-imprinted Polypyrrole[END_REF][START_REF] Ratautaite | Molecular Imprinting Technology for Determination of Uric Acid[END_REF], tryptophan [START_REF] Ratautaite | Electrochemical Sensors based on L-Tryptophan Molecularly Imprinted Polypyrrole and Polyaniline[END_REF], etc.), or large molecular weight objects (e.g. proteins [START_REF] Ratautaite | Molecularly Imprinted Polypyrrole based Sensor for the Detection of SARS-CoV-2 Spike Glycoprotein[END_REF][START_REF] Ratautaite | Evaluation of the interaction between SARS-CoV-2 spike glycoproteins and the molecularly imprinted polypyrrole[END_REF][START_REF] Ramanaviciene | Molecularly imprinted polypyrrole-based synthetic receptor for direct detection of bovine leukemia virus glycoproteins[END_REF], DNA [START_REF] Ratautaite | Molecularly Imprinted Polypyrrole for DNA Determination[END_REF], viruses [START_REF] El Sharif | Evaluation of electropolymerized molecularly imprinted polymers (E-MIPs) on disposable electrodes for detection of SARS-CoV-2 in saliva[END_REF], or bacteria [START_REF] Pintavirooj | Biosensors for Klebsiella pneumoniae with Molecularly Imprinted Polymer (MIP) Technique[END_REF]). Numerous traditional immunoanalytical methods provide precise measurements of different analytes. However, most of these methods, including the enzyme-linked immunosorbent assay (ELISA), depend on the use of expensive immune chemicals and/or lengthy analyte determination methodologies, as well as high-end tools, and are required to be operated by a specialist. MIPs provide a wide range of possibilities for the development of biosensors including low-cost, easy preparation, advanced storage stability, quick read-out time, good specificity, and the possibility of clinical or point-of-care testing. MIP-based sensors in comparison with antibodies or receptors-based sensors offer superior chemical and thermal stability. Thus, MIP-based electrochemical biosensors have become very attractive for the detection of disease biomarkers. The extraction of proteins from polymer films, the reusability of these imprinted protein-based sensors, conformational changes of the proteins during the imprinting phase, and the proper orientation of the proteins during the imprinting phase are the difficulties associated with molecular imprinting of proteins [START_REF] Ramanavicius | Advances in Molecularly Imprinted Polymers Based Affinity Sensors (Review)[END_REF]. The imprinting of small molecules is less complicated compared to macromolecules, for instance, proteins. The diffusion of proteins into the cavities imprinted in the polymer matrix is greatly hindered by their vast size. Functional monomers, highly reactive free radicals, cation radicals, or organic solvents can affect the proteins or amino acids during the polymerization process and it can alter the morphology of the imprinted cavities. The tertiary and quaternary structure of protein templates may be affected by the sum of all these processes, which would reduce the sensitivity and selectivity of the developed biosensor, thus, there are relatively few selective biosensors for diseases' proteins based on MIPs [START_REF] Dabrowski | Nanostructured molecularly imprinted polymers for protein chemosensing[END_REF][START_REF] Ansari | Molecularly imprinted polymers for capturing and sensing proteins: Current progress and future implications[END_REF]. Also, some drawbacks of MIPs previously were emphasized [START_REF] Crapnell | Molecularly imprinted polymer based electrochemical biosensors: Overcoming the challenges of detecting vital biomarkers and speeding up diagnosis[END_REF]. As drawbacks of MIPs, studies noted difficulties with electropolymerisation, especially the mass production, and bulk polymerization due to heterogeneous binding sites and other methods that provide a poor synergy with the electrochemical detection [START_REF] Crapnell | Molecularly imprinted polymer based electrochemical biosensors: Overcoming the challenges of detecting vital biomarkers and speeding up diagnosis[END_REF].

Different combinations of monomers, initiators, cross-linkers, and solvents are used to create MIPs. In aqueous solutions or organic solvents, electrically conducting polymeric structures are conducted at room temperature. Flexible MIP synthesis offers a significant benefit for imprinting biomolecules, it provides an opportunity to elude conformational changes and denaturation. Although, MIP-based assays have demonstrated competitiveness with assays like ELISA in terms of specificity, sensitivity and compatibility with technologies like lateral flow lab-on-a-chip, the commercial potential of these assays has not yet been completely realized [START_REF] Lowdon | MIPs for commercial application in low-cost sensors and assays -An overview of the current status quo[END_REF].

In pursuance to create a suitable template for MIP, many different conducting polymers are used. Due to their various qualities and biocompatibility, conducting polymers have been extensively used in the fields of bioanalytical and biomedical research, drug delivery, tissue engineering, and cell culture. Conducting polymers' most favoured characteristics include electrochemical activity and conductivity, mechanical elasticity, biocompatibility, and environmental stability. These qualities are necessary to improve the sensing capabilities of the analytical and bioanalytical systems [START_REF] Ramanavicius | Conducting Polymers in the Design of Biosensors and Biofuel Cells[END_REF]. Because of their electrical properties, which enable the conversion of biochemical data into electrical signals, conducting polymers provide the most promising materials for the biosensors [START_REF] Lakard | Electrochemical Biosensors Based on Conducting Polymers: A Review[END_REF]. Conducting polymers can be prepared by polymerization from the chemical [START_REF] Leonavicius | Polymerization Model for Hydrogen Peroxide Initiated Synthesis of Polypyrrole Nanoparticles[END_REF][START_REF] Kausaite-Minkstimiene | Evaluation of chemical synthesis of polypyrrole particles[END_REF], electrochemical oxidative techniques [START_REF] Ratautaite | Characterization of caffeine-imprinted polypyrrole by a quartz crystal microbalance and electrochemical impedance spectroscopy[END_REF][START_REF] Plausinaitis | Evaluation of Electrochemical Quartz Crystal Microbalance Based Sensor Modified by Uric Acid-imprinted Polypyrrole[END_REF], or enzymatic [START_REF] Kausaite-Minkstimiene | Evaluation of amperometric glucose biosensors based on glucose oxidase encapsulated within enzymatically synthesized polyaniline and polypyrrole[END_REF][START_REF] Ramanavicius | Fluorescence study of glucose oxidase self-encapsulated within polypyrrole[END_REF][START_REF] Kausaite-Minkstimiene | Enzymatically synthesized polyaniline layer for extension of linear detection region of amperometric glucose biosensor[END_REF][START_REF] Ramanaviciene | Visualization of red-ox proteins on the gold surface using enzymatic polypyrrole formation[END_REF], etc. Cyclic voltammetry is the most used technique for electropolymerized conducting polymers. It is also feasible to control the polymer thickness by adjusting the voltage range [START_REF] Crapnell | Recent Advances in Electrosynthesized Molecularly Imprinted Polymer Sensing Platforms for Bioanalyte Detection[END_REF].

The application of MIPs for the determination of Alzheimer's disease

As the population of many developed countries ages, the World Health Organization predicts that neurodegenerative diseases such as Alzheimer's disease (AD) and other forms of dementia, as well as conditions like Parkinson's disease and amyotrophic lateral sclerosis, will overtake cancer to become the second leading cause of death after cardiovascular disease by 2040 [START_REF] Gammon | Neurodegenerative disease: Brain windfall[END_REF].

AD is a multifactorial neurodegenerative disease. Its pathogenesis has been attributed to the extracellular deposition of amyloid β plaques, the intracellular neurofibrillary tangles that are made of hyperphosphorylated-Tau protein, and synaptic, and neuronal loss. These factors mostly damage cortical and limbic areas of the human brain [START_REF] Tiwari | Alzheimer's disease: pathogenesis, diagnostics, and therapeutics[END_REF]. The accurate diagnosis of AD is complicated and mostly performed by invasive, time-consuming, and expensive analysis like cerebrospinal fluid analysis or neuroimaging techniques such as positron emission tomography and magnetic resonance imaging. Since no inexpensive test to diagnose AD using biomarkers at all stages of the disease has been developed, new detection methods such as MIP-based electrochemical biosensors are being developed to address this limitation. The biomarkers that are the most indicative of AD are amyloid-β peptides (Aβ40 of 40 amino acids and Aβ42 of 42 amino acids), total-Tau, and phosphorylated-Tau (p-Tau). Because of their hydrophobicity, amyloid-β peptides can bind to plasma proteins, resulting in incorrect results of the analysis. Usually, proteins and other substances made by brain cells are detected in cerebrospinal fluid but also it could be measured by sensitive blood tests [START_REF] Li | Validation of Plasma Amyloid-β 42/40 for Detecting Alzheimer Disease Amyloid Plaques[END_REF]. Although these biomarkers are promising molecules for the detection of AD, further investigation is still needed [START_REF] Brazaca | Applications of biosensors in Alzheimer's disease diagnosis[END_REF]. Besides, the asymptomatic AD phase can last decades [START_REF] Huang | Alzheimer Mechanisms and Therapeutic Strategies[END_REF]. The physiological levels of Aβ42 in the cerebrospinal fluid of AD patients are reported to be less than 500 pg/mL [START_REF] Ganesh | Recent advances in biosensors for neurodegenerative disease detection[END_REF]. AD is characterized by the production and deposition of amyloid-β oligomers in the brain, therefore, this peptide is a promising biomarker in the diagnosis and monitoring of AD progression.

MIPs of amyloid-β oligomers

In recent years, it has been suggested that cerebrospinal fluid measurement of β-amyloid peptides, especially Aβ42 and Tau proteins, including total and phosphorylated forms of Tau, may alter the positron emission tomography image in determining the pathophysiology of AD. In cerebrospinal fluid, the changes observed include a 50% reduction of Aβ42 as a consequence of amyloid deposition in the brain. The changes also include an increase in p-Tau and total-Tau. In clinical practice, the use of Aβ42 as a biomarker for AD is largely limited by the absence of reference values. Measurable values of Aβ42 in plasma of cognitively normal individuals ranged from 8.12 to 29.00 pg/mL [START_REF] Zecca | Plasma β-amyloid1-42 reference values in cognitively normal subjects[END_REF]. The levels of the cut-off of 680 pg/mL for abnormal cerebrospinal fluid Aβ42 were also determined [START_REF] Bertens | Unbiased estimates of cerebrospinal fluid β-amyloid 1-42 cutoffs in a large memory clinic population[END_REF].

R. Dehdari Vais et al. [START_REF] Vais | A β-Amyloid(1-42) Biosensor Based on Molecularly Imprinted Poly-Pyrrole for Early Diagnosis of Alzheimer's Disease[END_REF] approached the MIP-based biosensor for Aβ42 detection. Pyrrole monomer was electropolymerized on a screen-printed carbon electrode in the presence of an Aβ42 template. Polypyrrole was chosen as a polymer film because of its easy electropolymerization and good stability in biological samples with neutral pH values. To evaluate the effectiveness of the biosensor, it was tested for the detection of Aβ42 in artificial cerebrospinal fluid and the results confirm the applicability of the biosensor for the diagnosis of AD. Based on the calibration curve, Aβ42 could be determined in cerebrospinal fluid by a LOD of 2.3 pg/mL. A low LOD of 1.2 pg/mL was achieved, indicating the suitability of the biosensor for the detection of Aβ42 at clinically relevant levels. Graphite and some other carbon-based electrodes can be modified by roughing, increasing surface area or oxygenated functional groups on the surface, M.V. Pereira et al. [START_REF] Pereira | Paper-Based Platform with an In Situ Molecularly Imprinted Polymer for β-Amyloid[END_REF] designed for the first time a MIPbased electrochemical biosensor for Aβ42 on a flexible paper platform. The carbon ink electrode was doped on the paper support, the poly(3,4-ethylenedioxythiophene) and amino thiophenol were used as a pretreatment and finally, the poly(o-phenylenediamine) MIP film was polymerized to trap Aβ42 molecules. In comparison to metal electrodes, carbon provides many advantages due to its low cost, wide range of possibilities, and high chemical stability. Commercial serum was used to test this designed biosensor. A Biosensor showed good sensitivity (LOD is 0.067 ng/mL with a linear range from 0.1 ng/mL to 1 μg/mL) in a healthy individual's blood sample. This biosensor could be improved in the future to determine the reference level of amyloid in the blood of patients with AD.

MIP techniques for Aβ42 detection were first applied by F.T.C. Moreira et al. [START_REF] Moreira | Smart naturally plastic antibody based on poly(αcyclodextrin) polymer for β-amyloid-42 soluble oligomer detection[END_REF]. αcyclodextrin was implemented to trap target molecules on a polymer matrix layered on top of conducting polymer polyaniline layer. The LOD value of such MIP was 0.20 ng/mL. Later the same group improved the biosensor [START_REF] Moreira | Redox probe-free readings of a β-amyloid-42 plastic antibody sensory material assembled on copper@carbon nanotubes[END_REF] by using polyaniline as a polymer matrix to entrap target molecules and used nanoparticles modified with copper oxide as conducting substrate for enriched electrolytic activity and electron transferability. Copper and copper oxide show notable electrocatalytic activity among other electroactive materials. The copper oxide nanowires, with their increased surface-to-volume ratio, provided an improvement in detection sensitivity. Significant improvement was obtained reaching a LOD of 0.4 pg/mL in a range from 0.1 ng/mL to 66.0 ng/mL in diluted blood samples without the need to incubate an active redox element on the working electrode under optimal conditions. This biosensor showed satisfactory results in Aβ42 detection for AD patients. To make the results more sensitive, several modifications can be made at once. N. Ozcan et al. [START_REF] Özcan | Electrochemical detection of amyloid-β protein by delaminated titanium carbide MXene/multi-walled carbon nanotubes composite with molecularly imprinted polymer[END_REF] formed a highly sensitive MIP/target/aptamer sandwich of delaminated titanium carbide MXene and multi-walled carbon nanotubes (MWCNTs) composite including a MIP assay for β-amyloid protein recognition. Delaminated titanium carbamide MXenes are easy to make and possess a high electrical conductivity, while MWCNTs prevent MXenes from aggregation. The biosensor showed a very low 0.3 fg/mL threshold of detection. The recovery in blood plasma was 99.99% -100.04%. These results seem to bring out the relevant role of highly sensitive electropolymerized pyrrole as a template entrapment matrix, MWCNTs as electrode modifiers, and the benefit of MXene as electrode construction material. Based on the low LOD of this biosensor, it may be a suitable sensing platform for the detection of β-amyloid in the blood of patients with AD.

MIP technology with conducting polymers has been used in AD sensors also to detect chemicals found even in the breath of AD patients. S. Emam et al. [START_REF] Emam | A Molecularly Imprinted Electrochemical Gas Sensor to Sense Butylated Hydroxytoluene in Air[END_REF] developed an innovative butylated hydroxytoluene air sensor and chose pyrrole as a conducting functional monomer due to its well-studied properties. It is important to note that non-invasive and less stressful interventions than blood or cerebrospinal fluid tests are important in AD diagnostic sensors research, and MIP is a suitable technology for this purpose.

The most sensitive platform for β-amyloid was created by N. Ozcan et al. [START_REF] Özcan | Electrochemical detection of amyloid-β protein by delaminated titanium carbide MXene/multi-walled carbon nanotubes composite with molecularly imprinted polymer[END_REF], combining polypyrrole with d-Ti3C2TX MXene and MWCNTs. F.T.C Moreira et al. [START_REF] Moreira | Redox probe-free readings of a β-amyloid-42 plastic antibody sensory material assembled on copper@carbon nanotubes[END_REF] used polyaniline modified with copper oxide resulting in low LOD. R. Dehdari Vais et al. [START_REF] Vais | A β-Amyloid(1-42) Biosensor Based on Molecularly Imprinted Poly-Pyrrole for Early Diagnosis of Alzheimer's Disease[END_REF] study also showed satisfactory results by entrapping molecules just in polypyrrole. It can be concluded that polypyrrole is a suitable and commonly used polymer for the detection of AD markers in the blood, cerebrospinal fluid, and even breath.

MIPs of p-Tau

p-Tau is usually examined in cerebrospinal fluid but can also be identified in blood, values vary due to different isoforms, age, stages of AD disease, and other factors. A. Ben Hassine et al. [START_REF] Ben Hassine | Novel Electrochemical Molecularly Imprinted Polymer-Based Biosensor for Tau Protein Detection[END_REF] reported an electrochemical biosensor based on a MIP for p-Tau-441 protein detection. 3-aminophenol as a monomer was chosen because poly(3-aminophenol) is beneficial for high permselectivity, and simple control of polymer density that self-limits its growth. The stability of the target protein is favoured by its interaction with the amine and hydroxyl groups during the rebinding step. The LOD of this biosensor was 0.024 pM in buffer and 0.067 pM in spiked and diluted human serum samples. This suggests that other molecules present in the serum may interact with vacancy recognition and affect sensitivity. The results have shown a good overall performance of precision and LOD, and in the future, it may be suitable for the detection of p-Tau protein.

Analysing a mixture of currently examined markers such as β-amyloids and Tau proteins in combination with neurotransmitters and genetic markers from blood samples could improve the usual laboratory methods, allowing the AD diagnostic test to be made available to the general population. Given the global incidence of AD, there is still a need for a low-cost, environmentally friendly biosensor with high stability and selectivity in many circumstances.

The application of MIPs for the determination of Parkinson's Disease

Protein misfolding disorders are the term used to describe neurodegenerative diseases such as AD and Parkinson's disease. α-Synuclein is a protein containing 140-amino acids (14.3 kDa). α-Synuclein protein accumulation in the neuronal cell body ('Lewy bodies') and neurites ('Lewy neurites') is related to all cases of Parkinson's disease [START_REF] Ganesh | Recent advances in biosensors for neurodegenerative disease detection[END_REF][START_REF] Ma | A nanospherical conjugated microporous polymergraphene nanosheets modified molecularly imprinted electrochemical sensor for high sensitivity detection of α-Synuclein[END_REF]. α-Synuclein has been detected in cerebrospinal fluid, blood, saliva, skin (cutaneous nerves), enteric nervous system, and retina of Parkinson's disease patients [START_REF] Ganguly | Alpha-Synuclein as a Biomarker of Parkinson's Disease: Good, but Not Good Enough[END_REF]. Thus, it could be a marker of PD, and its level may be an important factor in the severity of the disease.

Y. Ma et al. [START_REF] Ma | A nanospherical conjugated microporous polymergraphene nanosheets modified molecularly imprinted electrochemical sensor for high sensitivity detection of α-Synuclein[END_REF] synthesized a biosensor for α-Synuclein detection. The sensor was made of a GCE electrode modified with graphene nanosheets and nanospherical conjugated microporous polymer with the imprinted template α-Synuclein. Porous organic polymers in particular stand out due to their distinctive morphologies, customizable design, and various preparation techniques. Conjugated microporous polymers, a subset of porous organic polymers, are a type of material with a 3D network, a durable nanoporous structure, and a framework with a π-electron conjugated structure resulting in higher thermal and chemical stability, bigger surface areas, and precisely calibrated porosity. The LOD of 3.5×10 -5 ng/mL was achieved on this sensor and the results in serum showed the potential for diagnosing Parkinson's disease in the early stages.

α-Synuclein can be accurately detected in cerebrospinal fluid by various methods of immunoassays (ELISA and electrochemiluminescence); serum and plasma levels can be carried out using standard immunoassays, single-molecule sandwich immunoassays, and ELISA. However, these kinds of methods are expensive and require laboratory preparation, it makes sense to develop a simple, inexpensive, and portable α-Synuclein detection sensor.

MIP application for detection of stress biomarker α-amylase

Saliva collection is non-invasive, relatively simple, less likely to cause stress, and can reflect real-time levels of biomarkers. The most valuable potential markers of stress in saliva are cortisol, lysozyme, α-amylase, and Chromogranin A [START_REF] Chojnowska | Salivary Biomarkers of Stress, Anxiety and Depression[END_REF]. Acute stress is associated with activation of the sympatho-adreno-medullary system, which is reflected by salivary α-amylase and chromogranin A. Salivary amylase levels rise considerably faster than cortisol in response to psychological stress, showing that it is a superior stress indicator. The enzyme is also thought to be an indicator of a state of calm or relaxation [START_REF] Takai | Effect of psychological stress on the salivary cortisol and amylase levels in healthy young adults[END_REF]. Normal α-amylase ranges in blood serum 0.05-0.125 U/mL and saliva 19-308 U/mL [START_REF] Soo-Quee Koh | The use of salivary biomarkers in occupational and environmental medicine[END_REF]. As a result of increased physiological and psychological stress, the concentration of α-amylase in saliva (above 0.5 mg/mL) rises.

T.S.C.R. Rebelo et al. [START_REF] Rebelo | A Disposable Saliva Electrochemical MIP-Based Biosensor for Detection of the Stress Biomarker α-Amylase in Point-of-Care Applications[END_REF] developed a disposable point of care stress biomarker αamylase using MIP technology with a LOD of 3.0×10 -2 mg/mL in human saliva. First, a cysteamine self-assembled monolayer was formed on the AuSPE, then the pyrrole was electropolymerized. In the rebinding process, the obtained sensor demonstrated high sensitivity and selectivity on α-amylase in human saliva and a buffer solution containing other biomarkers. With a portable system and disposable chips, this MIP biosensor demonstrated analytical capabilities as a suitable candidate for diagnostic point-of-care testing devices for the detection of α-amylase in saliva.

From the reviewed studies, it can be concluded that electrochemical biosensors based on MIP technology can be applied to detect Aβ42 p-Tau 441, α-synuclein, and α-amylase. This suggests that MIPs can be used to detect neurodegenerative diseases such as Alzheimer's and Parkinson's disease as well as to identify patients dealing with stress. Conducting polymers are an excellent choice for precise and simple MIP biosensing devices.

Conclusions

To conclude, this review article discusses the newest studies about electrochemical sensors for the detection of protein-based biomarkers for different diseases. Bearing in mind that more accurate and better detection methods are needed today, molecular imprint technology and biosensors based on MIPs are considered an alternative, due to their attractiveness, easy synthesis, price, and short laboratory testing time. This article reviews the application of MIP to the detection of biomarkers of Alzheimer's, Parkinson's diseases, and stress. After reviewing various MIP variants, it was assumed that conducting polymers are an excellent choice for precise and simple MIP biosensing devices. Moreover, polypyrrole is a suitable and commonly used polymer for the detection of AD markers in the blood, cerebrospinal fluid, and even breath. Electrochemical biosensors based on MIP technology can be applied to detect Aβ42 p-Tau 441, α-synuclein, and α-amylase.

MIP-based biosensors have a lot of potential for diagnostics. This review shows MIP's achievable detection limits. The ability to create such sensors quickly and efficiently contributes to a better quality of human life through more targeted diagnosis and detection of some neurodegenerative diseases.

  CRediT authorship contribution statement: Conceptualization: Ar. R. and V. R.; Writing -Original Draft: G. P., R. B., and V. R.; Writing -Review & Editing: Ar. R., D. P., M.B. and V. R.; Supervision: Ar. R.; Project administration: U. S.-B.; Funding acquisition: Al. R. and Ar. R.

Acknowledgements

This project has received funding from the Research Council of Lithuania (LMTLT), GILIBERT 2021 program agreement No S-LZ-21-4 and was co-founded by Campus France grant No. 46593RA (PHC GILIBERT 2021).

Declaration of Competing Interest

The authors declare no conflict of interest.