As Friedman (2009, 5) notes, "If worldwide processes are indeed powerful, they are articulated with local, specific lives and strategies which cannot just be regarded as having been produced by globalization."

The argument that I develop in this chapter is that in French Polynesia, the definition of Mā'ohi authenticity takes shape at the intersection of cultural policies, the tourist economy, and the cultural militancy of the EPM. Since the 1960s, the development of a tourist economy mainly concentrated in Bora Bora has played a role in defining Mā'ohi cultural "authenticity," progressively shaped around Polynesian musical instruments, songs, and dresses. Tourism professionals found their inspiration in pre-existing dance and song festivals, the most famous being the Heiva2 . During the 1970s, a French policy of institutionalization of the cultural sector strengthened the vitality of these cultural activities. It aimed to dissociate the promotion of Polynesian culture from the claim of political independence, a strategy similar to what Alban Bensa (2002, 186-187) has described in New Caledonia.

The cultural and indigenous claims driven by the EPM have prompted debate among more than just the Church clergy, as many Polynesian Protestants are also involved. References to the land and to Mā'ohi culture appear as a unifying principle. They symbolize the reshaping of peoples' memories of the past and of the relationships between individual and community. The cultural engagement of the EPM thus contributes to furthering representations of unity. However, due to an increasing individualization of biblical and cultural interpretations in a context of religious pluralization, I argue that so many diverse reappropriations of this cultural message have emerged that the homogeneity of the EPM's cultural renewal requires qualification. Thus, I begin by examining the work of the EPM Church's Theological Commission and the spread of its theology throughout the local Protestant churches of French Polynesia. This analysis leads to a discussion of how one of the local Protestant churches experienced that theology in particular. I consider how the local church of Papetoai in Moorea was the first to introduce a Mā'ohi celebration of the Lord's Supper.

Mission History

Protestant missionaries from the London Missionary Society (LMS) were present in Tahiti from 1797. Between 1842, when France established a protectorate on Tahiti and Moorea, and 1880 when the islands were annexed, it was increasingly difficult for British missionaries to sustain their activities due to the political context. From 1863 onwards, French missionaries from the Society of Evangelical Missions of Paris (SMEP) progressively replaced their British predecessors, striving to prove to the French administration that Protestants could also be French patriots. They have always linked mission work closely to processes of instruction and the "civilizing mission." The Westernization of norms (notably dress norms) and behaviors is one of the main legacies of the British missions. In contrast, at the end of the nineteenth century, the ambitions of French missionaries primarily focused on pastoral training and institutional organization.

At the beginning of the twentieth century, missionaries to the Pacific aimed to convert souls and discipline bodies. As noted by Eves (1996, 86) in his analysis of Methodist missions in Papua New-Guinea, "Conversion was confirmed in the eyes of the missionaries by the acquisition of a visibly distinct form of body, emblematic of Christian character."3 In Polynesia, the historian Claire Laux (2000, 145-148) argues that missionaries transformed Polynesian living by replacing open huts with closed houses and by introducing new moral norms, such as intimacy and modesty. From the missionaries' perspective women had to be particularly controlled. This was especially true of Polynesia, where women's free sexuality has been celebrated since circumnavigation began at the end of the eighteenth century. Women were regarded both as "temptresses" and as "natural allies" of the mission, which was supposed to break with pre-missionary gender inequality. The new clothing codes expressed this ambivalence. Inspired by the British missionaries' conception of "decency," they have also enabled Polynesian women to develop exclusive and valued spaces of feminine sociability based on sewing activities4. LMS missionaries were also concerned about Polynesian dances, which they regarded as sensual and provocative. In reaction to British missionaries' teachings, the religious movement Mamaia, which arose in the Windward Islands between 1826 and 1834, claimed free sexuality and the performance of "lascivious" dances. In doing so, the movement ostensibly contributed to transforming pre-Christian dances into an anti-Christian practice 5 .5 Therefore, the 1835-36

Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, missionary codes officially banned dances, which they explicitly understood as an act of rebellion against missionary authority (Richaud 2005, 443-444). Missionaries condemned dances for being both obscene and pagan6 .6 Therefore, missionaries not only banned them from the temple but also, at the end of the nineteenth century, the French Protestant missionaries forbade their parishioners to join in the National Day celebrations. Missionary reports regularly mention the "harmful effects" of this celebration, illustrating divergences between missionaries and the French administration on the modalities of the "civilizing mission": For all the Tahitian churches, the celebration of the National Day, which was given particular splendour this year, has been a sad stumbling block. Our poor indigenous people, caught between God's commandments and their hearts' desires, too frequently yield to the latter, tranquillising their minds with the fallacious pretext that what was established by the Government can't be bad. (...) But what a humiliation, as French people, to see obscene dances formerly banned by the Protectorate laws honoured in the false light of patriotism and provoking people into vice. (n.a. 1896, 286) At the same time, French missionaries from the SMEP worked against the French political authorities as they strove to organize independent local churches into one unified Church of Tahiti and Moorea. The French authorities feared that such a unified Church might become a political force, while the French missionaries primarily wanted to distance themselves from LMS congregationalism and to unify the Church by training an indigenous clergy. By the end of the nineteenth century, the figure of the farmer-pastor emerged from this historical convergence: from the missionaries' point of view, agriculture was indeed an efficient way to instil good Christian dispositions, such as steadiness, patience, and perseverance7. Besides the theological teaching, manual work, and agriculture became increasingly important in the teachings of the Theological School, as French Protestant missionaries vigorously aimed to deny accusations by the French administration that they were distracting Polynesians from agriculture with too-demanding church activities. They finally called the model of the farmerpastor into question and abandoned it during the 1960s-1970s. This period entailed major changes beyond the Church (with the deep external economic, political, and social turmoil following the establishment of the nuclear experimentation center) and within the Church (with its accession to autonomy). The Church then adopted a system of pastoral posting and Gwendoline Malogne -Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, circulation: this constituted the first step in a process of professionalization, as ministers no longer worked in their villages of origin, they could not cultivate their familial land, and had to devote themselves full-time to church members who were not family members. Migrations from remote islands to Tahiti and the subsequent population increase on this island8 amplified urbanization, while the primary economic sector declined, to the gain of tertiary activities9.

Cultural and Theological Renewal: An Independent Church

In 1963, a century after the arrival of the first missionary from the SMEP, the Church acceded to autonomy, which meant that Polynesian ministers succeeded French missionaries at the head of the Church. This autonomy should have preceded the political independence of French Polynesia, in a context of worldwide decolonization. However, this was not achieved. On the contrary, the establishment of the nuclear experimentation center (Center d'Expérimentations du Pacifique) in Moruroa and Fangataufa led to a deeper military, economic, and political dependence on France10 .10 The new autonomous Church became a full member of various French, regional, and international religious organizations: the Evangelical Community for Apostolic Action (CEVAA, gathering the churches stemming from the SMEP), the Pacific Conference of Churches (PCC, which combines Pacific Protestant and Anglican churches and, which in 1966, opened a Pacific Theological College, (PTC))11 and the World Council of Churches.

The Theological Commission of the EEPF was created during the 1970s under the auspices of the PCC and the CEVAA, which aimed to maintain strong relationships and theological exchanges between the newly independent churches. From the "indigenization of the service" Gwendoline Malogne -Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, in 1971 by the PCC, theological reflections moved to a perspective of contextualization, implying not only an adaptation of the biblical message to local cultures, but also reciprocal relationships between Gospel and cultures. Contextual theologies now emphasized the need to read the Bible from a given experience and situation. Klauspeter [START_REF] Blaser | Théologies contextuelles[END_REF]Blaser ( , 1152) ) points out that "by considering the cultural, social, political and religious context as the methodological core of any theological reflection and biblical interpretation, contextual theologies take part in an effort to get out of church and theological colonialism initiated by the missionary movement before the Third World political independence." Within Pacific Protestantism, the emphasis on local cultures and references to the essential link between Pacific Peoples and the land have been notably conceptualized by two Methodist theologians, a Tongan, Sione Havea and a Fijian, Ilaita Sevati Tuwere, who have respectively formulated a "theology of coconut" and a "theology of the land." The "theology of coconut," elaborated in the 1960s, developed the relevance of the coconut from a biblical perspective12.

French Polynesian minister, Tihoti Pittman has summarized its three main aspects: First, no one knows when the coconut is going to fall. This is a decisive moment that can be compared to the expectation of the coming of the Lord. Second, when it falls, the coconut rolls on land until it reaches the lower level, which gives, "an illustration of going to the deprived, the needy, the marginalized people" (Pittman 1990, 10). And third, "the coconut rolls into a river or the sea" (ibid.) where the stream and wind carry it along until the coconut reaches another land. "There it will take root and give life to another coconut tree" (ibid.). This imagery is akin to the British and Polynesian missionaries who sailed to "evangelize the Pacific Island peoples" (Pittman 1990, 10-11). In Tuwere's theology, the reference to the land encompasses mountains, rivers, and trees, as well as the people who live on the land, their traditions, beliefs, and ancestors:

In the economy of God, there cannot be two histories; one belonging to the missionary era brought about by and with missionary influence and expansion, the other a "dark" history of the receiving culture. There is only one history, the history of salvation in which the Trinitarian God is continually at work ... The history of the land and sea which includes our myths, and belief and value systems is part of this history of salvation. [START_REF] Tuwere | An Agenda for the Theological task of the church in Oceania[END_REF]( Tuwere , 11 cited in vidal 2011, 81) , 81) Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, According to Gilles [START_REF] Vidal | Les théologies contextuelles dans le Pacifique Sud au XXe siècle. Analyse des conditions de production d'un discours religieux en situation[END_REF], this historical perspective is one of the main innovations brought by Tuwere's theology of the land. However, this focus on land should not be understood as a re-sacralization of place, but rather his theology presents the land as a creation of God.

In French Polynesia during the 1980s, the Theological Commission began to orient its reflections toward cultural themes under the influence of its chairman Turo Raapoto. Paradoxically, Raapoto (who died in 2014) was not a clergyman but a lay church member who drew his legitimacy from his academic background (as the first French Polynesian to obtain a Ph.D. in linguistics), and his parentage (he was the son of the first Polynesian president of the Church, Pastor Samuel Raapoto). Turo Raapoto thus had a very specific position; he was neither a minister nor an employee of the church, but his educational and family background afforded him a greater freedom of expression-including criticism-within the church.

In 1988, the Commission edited the first pamphlet in Tahitian (reo Mā'ohi) designed for church leaders, entitled, "The sharing of God's word and the original Mā'ohi nature." The pamphlet provided a working base from which to stimulate new theological reflections. Its first conclusion was that the Mā'ohi individual has lost his identity and lives in moral poverty. The pamphlet notes that the Mā'ohi has become an ignorant person, ashamed to be Mā'ohi and obsessed by money and consumption (EEPF, Theological Commission 1988, 9). The second conclusion was that "moral poverty" is a reversible state: "just give his tongue back to the Mā'ohi and we will see if he is really ignorant" (Theological Commission 1988, 36). The Mā'ohi has indeed lost his identity, but he can recover it by becoming an actor of his own history, that is to say by speaking his tongue again and rediscovering his land. In Raapoto's thinking, the tongue is the real and only way of mediating an encounter between men and God. He defines language as a means of recalling the work of God. It is the "vehicle of the knowledge and wisdom of a people" (EEPF Theological Commission 1988, 7). He bases his reasoning on a specific understanding of Christian history in Polynesia: British missionaries revealed that God wanted to encounter the Mā'ohi people in their tongue and customs as through missionaries learning Tahitian and translating the Bible into Tahitian, into Tahitian (completed in 1838).

In July 2000 in Lifou (New Caledonia), CEVAA co-organized a workshop entitled "The theology of the land in the Pacific churches," suggesting a reorientation of theological reflection (CEVAA, 2001). The perfect mastering of reo Mā'ohi as a means of accessing God's word was not mentioned, and debates focused instead on the link between men and women and the land. Beyond questions of terminology-"cultural theology," "theology of the land," or "theology of Gwendoline Malogne -Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, liberation"13-the reflection of the Theological Commission continues to maintain the liberation of Mā'ohi people and the defense of Mā'ohi identity, through the preservation of tongue and land, as its primary concerns. The theological discourse elaborated by Raapoto not only seeks to value the expression of local culture within the temple but also gives a religious dimension to an exclusively cultural process. Not only are Polynesian and Protestant identities deeply intertwined, but the affirmation of a Protestant identity must involve living and behaving in a deeply Polynesian way: a Mā'ohi Protestant should live on his own land, harvest the fruits of this land, and speak the tongue of his ancestors out of respect for their memory and God's will.

Since the 1980s, this theological orientation has inspired several important stances of the EPM, notably against nuclear testing and the sale of indigenous lands. In 1982, the Church synod officially protested against nuclear testing in French Polynesia (Malogne-Fer 2003, 205-214).

Subsequently, the church has been very active in the anti-nuclear movement, with the support of ecumenical organizations. Since the end of nuclear testing in 1996, the EPM has continued to insist upon opening access to military archival information on the health consequences of nuclear experimentation, and it demands compensation for the victims of radiation exposure. The leaders of the church regard the reluctance of the French state in this domain as proof of its contempt for French Polynesians, thus underlining the intimate connection between nuclear testing and French colonialism.

The second major issue advocated by the EPM is inalienability and invaluable quality of indigenous land. In the 1980s, the church called on Mā'ohi people not to sell their lands, which are thought of as "a source of [their] cultural and spiritual roots" (Theological Commission 1999, 57-58). The church wrote, "This free gift from God should not be sold or given without consequences [for] life and its stability" (Theological Commission 1999, 57-58). In other words, land cannot be sold because it belongs to God and men are merely placed in charge of its management (Genesis 1:28). A scheme proposed by the Theological Commission in 1993 described nature as an unavoidable medium between men and God (see also Fer and Malogne-Fer, 2001, 76-77), or as:

13 Jacques Ihorai, president of the Church until 2003, advocated the use of "theology of liberation," but this appellation was not unanimously accepted. In everyday language, the use of terms like "turoïsts," "anti-turoïsts," or "pro-Turo" emphasizes the strong personalization of the Commission's work.

Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill,.

GOD NATURE MAN

The Theological Commission and Its Critics

This theological orientation has generated criticism. Just after the publication of the first pamphlet in 1988, a controversy arose between the head of the EPM and a French metropolitan military chaplain who condemned what he saw as an implicit idea of an exclusive love of God for the Mā'ohi people14. Further criticisms have tended to show how the emphasis put on identity issues did overshadow a reflection on social, gender, and generational inequalities. The anthropologist Alain [START_REF] Babadzan | Du syncrétisme au traditionalisme, Les cahiers du Vea Porotetani[END_REF] considers this theology as part of contemporary nostalgic reinterpretations and revaluations of the past that ignore any analysis of social inequalities in French Polynesia. He notes, "Criticism of class inequalities gets short-circuited by a discourse that only recognizes ethnic and cultural differences" (Babadzan 1997, 39-41).

Criticism has also emerged within the church, with Pastor Tihiri Lucas pointing to an intergenerational breakdown within the French Polynesian society. According to him, the theology taught at the Theological School and much appreciated by the students does not give them relevant tools to face everyday problems or individual suffering. There is, in fact, a gap between this theological orientation and the expectations of a large part of the population, especially the youth, who are attracted by consumer society and the Western way of life and are unconcerned with cultivating taro patches.

Finally, my own doctoral research has shed light on the conflict between the Church's promotion of gender equality in church leadership positions and the Commission's rejection of it. The synod-the governing body of the church-authorized the admission of women to the ministry in 1995, arguing that, "nothing in the Bible forbids women from becoming ministers."

The promoters of this decision-who did not seek the advice of the Theological Commission on this issue-presented it as "theological," while labelling opposing arguments as "cultural," and therefore disqualified. Thus, all the male ministers interviewed in 2000-2002 claimed that Leiden & Boston,Brill, they supported this decision, and reinforced their theological position by adopting a historicist reading of the Bible (where unfavourable biblical verses are considered in their historical context). Yet, while two thirds of theological student graduates are women, women still do not have full acceptance as theologians-the Theological Commission is composed exclusively of men, ministers and deacons. Nor are women involved in the work of theological production within the church. This is largely because the Commission's theological discourse draws on certain aspects of the Polynesian culture that tend to provide new arguments, now labelled as "theological," to the opponents of women's ordination. For example, in the theology of Turo Raapoto, (1977, 14, 35-36) the idealization of a Polynesian past notably includes the will to rehabilitate the marae, the sites of worship of the pre-missionary period. One of the characteristics of the marae is that maintenance of their "purity" implies a prohibition of women from entering such places. In 2008, Turo Raapoto took a stance against the ordination of women. In doing so, he openly challenged an important decision made by the Church thirteen years earlier, thereby underlining the increasing strength and independence of the Theological Commission. But, to what extent does this theological orientation reflect the opinions and beliefs of the church members? In addition, how do the French Polynesian local churches actually receive the teaching of the Theological Commission?

The Spread of Cultural Renewal: Advocacy and Dissent

Cultural renewal in the EPM has led to a number of modifications to the liturgy. One of the most overt changes is that reo Mā'ohi is used exclusively during services. On this issue, the Church distinguishes itself from the other local Churches-notably Catholics, Pentecostals, and Adventists who have opted for bilingualism (French/reo Mā'ohi)-in a context marked by the widespread use of French in everyday life15. There has also been an attempt to make the liturgy less austere and the place of worship more open to its environment by integrating symbols of Polynesian nature and culture. In this spirit of openness, the head of the church authorized the introduction of elements previously banned from the temple: musical instruments, flowers, Polynesian clothes, and the Communion ritual with bread and wine replaced by local products 15 The 2007 census shows that the use of French is increasingly widespread, as it is becoming the language of everyday life, while the number of French Polynesian graduates has also increased. In Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, such as coconut flesh and water or 'uru (breadfruit). Parishioners strongly debate these changes because they remain optional:

The Synod recalls that the freedom is given to local churches to use instruments, symbols and other means of expression during the service, subject to the agreement of parishioners involved, after they will have reflected on the new significance brought by this new form of communication16.

The promoters of this "openness to the world" aim to seduce the church youth, who like to praise God with traditional (guitar, ukulele) and modern musical instruments (keyboard), while opponents regard these new instruments associated with "the street" and drinking parties as an importation of society's evils into the temple, and thus, a profanity.

The use of flowers (in bouquets, in wreaths, or worn behind an ear) also raised discussion but church members more readily accepted this. Most of the parishes in the Austral Islands continue to object to these changes out of respect for their tradition inherited from elders, along with other considerations. On the one hand, flowers are expensive, and more importantly, parishioners felt they did not need to decorate the temple, as the presence of church members at the service was enough to "beautify" the place of worship. On the other hand, the promoters of flowers pointed out the contradiction in not allowing flowers at regular services, yet permitting them on coffins during funerals.

The modification of dress codes for deacons and ministers has encountered stronger resistance.

Local churches in Moorea and the Tuamotu-Gambier were the first to break with tradition by authorizing deacons to wear a simple shirt at the church service, instead of the former longsleeved jackets. However, this change to a light dress, more appropriate to the local climate, conflicts with the traditional view of deacons and ministers as men set apart and distinctively attired from ordinary church members. This modification of clothing codes may go as far as the wearing of a pareo, a piece of fabric tied around the waist in lieu of trousers. Yet, only a few ministers dare to wear a pareo at church services, and the significance of this practice differs widely. For Pastor Henri Germain from Moorea, the pareo is a sign of humility (Interview with Pastor Henri Germain, 19 June 2002), while according to Pastor Matahi Hiro-and this belief is widespread-the pareo is intended for intimacy in the home: Women deacons and ministers never wear a pareo in the temple, as they are required to cover their bodies more so than men. The debate around the liberation of deacon and minister dress codes primarily applies to men, at a time when an increasing proportion of women are reaching these same church positions.

In all these discussions raised by the liturgical changes driven by the cultural renewal, the advocates of the tradition always invoke the respect due to elders who had preserved the missionary legacy to refuse such innovations. This gap separating "young" from "elders" is particularly deep when it comes to the modification of the elements of the Lord's Supper. A few churches in Moorea and in the Tuamotu and Marquesas Islands introduced the Mā'ohi Communion into their liturgy in the 2000s. Replacing bread and wine with coconut flesh and water was inspired by Havea's theology of the coconut. As Joel Hoiore, director of the Theological School, explains, "Elements are like a medium, so let us use, promote, and rehabilitate what is already here" (Interview with Pastor Joël Hoiore, 6 June 2002). Local churches had various reasons to adopt this Mā'ohi Communion. In the Tuamotu and Marquesas, for example, where Protestantism is a small minority, these local churches aimed to show their attachment to the EPM by welcoming the Theological Commission and its teaching. By comparison, in Moorea most of the local churches adopted this innovation partly because some leaders of the Theological Commission were native from Moorea and, therefore, they could convince church members to accept the change more easily. Moreover, there was also a strong presence of English-speaking tourists in Moorea (especially in the temple of Papetoaimentioned in travel guides), which led the Church to post ministers fluent in English there. These ministers also happened to be trained in Pacific contextual theologies (at the Pacific Theological College in Fiji), such as the Mā'ohi Communion, and were strong advocates of them.

One of the questions raised by cultural renewal-in all of its liturgical forms-is whether it leads to a de-sacralization of the temple or a re-sacralization of nature. The promoters of this cultural renewal aim to transform the temple into an accessible and inclusive place "open" to the Polynesian environment and culture. In fact, the boundaries between inside and outside tend to shift rather than disappear. For example, the first musical instruments introduced into the temples have been permanently "installed." Coconuts and 'uru used for the Lord's Supper are subject to specific requirements: they come from trees located in the immediate vicinity of the temple, and should not fall onto the earth but be picked with a net. Some church members interpreted the introduction of the coconut as a way of reinforcing the sacredness of the Lord's Supper as the flesh of coconut is white and pure and has not been produced or touched by men's hands-unlike bread.

While the promoters of cultural renewal see Mā'ohi identity as the only way to gain religious salvation, advocates of the Protestant tradition consider the introduction of a new liturgy disrespectful to the elders and regard faithful adherence to missionary heritage as an inherent feature of Polynesian Protestantism. Both sides claim an authentic religion. In the first case, authenticity is measured by conformity to Polynesian cultures; in the second case, it is authentic towards an inherited tradition. Here religion is a matter of memory. The act of believing is defined as, "belonging to a chain of memory" (Hervieu-Léger 1993) and is legitimated by the authority of a tradition. This tradition itself is reinterpreted, so that Christianity becomes the "best of tradition," as Jeudy-Ballini (2002,63) noted in her study of Sulka people (New Britain). To Sulka people, Christianity "contributes in a way to bring memory back, by revealing to [the Sulka] the meaning of their own traditions and values" ( Jeudy-Ballini 2002, 63).

As the EPM engages with culture, it creates internal diversification and pluralism at different levels of Church life, including, the Synod, the arrondissement, and the local church. The diffusion of ideas underlines the autonomy of the Theological Commission vis-à-vis church hierarchical structures. As the Commission circulates independently from one parish to another, firstly, it develops networks and teachings that differ from the teachings of the Theological School. Secondly, while freedom is given to local churches to embrace or reject the orientations of the Theological Commission, official decisions to do so are only made by a few of the deacon's committee. This, in turn, raises questions about the legitimacy and representativeness of this committee. Jean Tehaapapa, vice-president of the Church and former president of the Theological Commission, points out the limits of this organization:

I believe the misfortune we had with these two kinds of Communion occurred because we didn't take the minority's opinion into account. That's our weakness: when you're a local minister, if you don't listen to the minority, then the risk is that the majority always obtains satisfaction while it creates discontent, instead of looking for consensus. That's not easy and that's what happened in Papetoai. (Interview with J. Tehaapapa, 9 feb. 2010)

Throughout the 1990s, the church of Papetoai in Moorea was one of the pioneer local churches of the EPM. However, in the 2000s, it came to be viewed as a church not to follow due to the Gwendoline Malogne -Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, tensions that constant changes generated within it and with other local churches in Moorea. The influence of the strong tourist economy in Moorea (non-existent in the Austral Islands) is one factor that explains the variable success of the Theological Commission's teachings on different islands. Nevertheless, tourism is not the only influence, as it does not explain why the local church of Haapiti in Moorea has kept traditional liturgy while its neighbor Papetoai has become a "virtuoso of change," as I discuss next.

The Papetoai Protestant Local Church and Its Communion: Between

Exemplar and Exception

In September 1999, the Protestant church of Papetoai split into two parts because some parishioners objected to theological and liturgical changes. At the initiative of a deacon, Firipi Teihotaata, half of the parishioners founded an independent Church, registered as a religious association, and became a member of a federation of Protestant dissident churches. The current president of this church and son of Firipi Teihotaata, Marirai Teihotaata, explains this dissidence as follows:

Concerning our organization, since the split from the church located on the seaside, we have taken back the old organization, as our grandfathers did. My grandfather was head deacon in the church, and that's the organization we maintain today. We don't want to forget these practices. (Filmed interview with M. Teihotaata, 20 feb. 2010)

The case of the Papetoai church throws light on the close intertwining of cultural renewal with local histories and social relationships, as well as on the questions and diverging interpretations that this renewal generates.

The impetus for the Papetoai split began on Christmas night 1996. It was then that Deacon Bruno Rupea unilaterally decided to change the communion of bread and wine for coconut flesh and water, informing the pastor (Adrien Flores, an advocate of cultural renewal) of the change only during the service. To justify this initiative, he used a common figure of Polynesian rhetoric, exhorting parishioners to act in coherence with the teaching given by the Theological Commission:

Me and my wife, we were about to prepare the Lord's Supper. As in October, the whole month of October, there were meetings with Turo Raapoto, and that's his teaching; he pushed parishes to do so because God gave us this mā'a [food], this water, why not put them on the Lord's

Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill,. Papetoai was the first local church to adopt the Mā'ohi communion, and the introduction of these Mā'ohi elements prompted some church members to go elsewhere and attend the Lord's Supper on the first Sunday of each month at the nearby village of Haapiti. In 1999, as an alternative to this pattern, Pastor Kelly, who succeeded Adrien Flores at Papetoai, tried to please both those who supported and those who opposed the liturgical innovations in Papetoai by trying to organize two separate Lord's Supper services. He decided either to offer simultaneously or to alternate the two versions of the Lord's Supper: the traditional (bread and wine) and the Mā'ohi ('uru and coconut). Pastor Kelly's plan was never implemented, and his attempts to unify the church ironically ended up having the opposite effect: the church soon split into two. While the Lord's Supper is supposed to symbolise community unity through sharing the same food, church members were faced with the decision of choosing either one or other of the two competing ceremonies, thus deepening dissensions by throw-ing them into harsh light and compromising any chance for reconciliation.

A visit by the president of the EPM with a delegation of pastors finally brought the parish dispute to its climax, and led to the establishment of an independent church17. Meanwhile, Adrien Flores, who had been elected as the president of the third arrondissement of the EPM, which includes all the local churches of Moorea, was among the delegates. He refused to accept that the Mā'ohi Communion he had been partly responsible for introducing in Papetoai a few years before could be called into question, as once a church is "open" to the Mā'ohi Communion, it is considered that this church cannot "step back." During the 1990s and 2000s, several young ministers used cultural renewal to reinforce their authority by introducing new biblical interpretations that challenged traditional interpretations of local deacons and "elders."

Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, Now the ministers newly posted in a local church have to cope with the preexisting orientation of this church, whatever their personal opinion on the teachings of the Theological Commission.

The events in Papetoai throw light on some patterns of Polynesian sociability and church organization. Cultural activism is not an end in itself but is entangled in local social relationships and long-term conflicts within the local church, fueled by reversals of alliances, personal rivalries, and old competition between Polynesian families. In Papetoai, for example, the deacon who led the dissidents, Firipi Teihotaata, first spoke out for the Mā'ohi Communion, but then changed his mind when the pastor refused to ordain his son as his successor in a deacon's position. This father-to-son (or uncle-to-nephew) transmission of the deacon's post takes place within a church organization structured by 'āmuira'a-parish subgroups based on familial membership and/or spatial divisions which contribute to the entanglement of family, territorial, and church belonging. From Deacon Firipi Teihotaata's point of view, to maintain a representative from his family within the deacons' committee was more important than the theological and liturgical changes.

Liturgical innovations are introduced on specific celebrations (Christmas, New Year's Day, the church's annual fundraising). The festive context legitimizes their exceptional nature and such liturgical alterations can be justified by invoking the satisfaction of church members, the absence of God's sanction, and the impossibility of "stepping back." This last argument points to an ideological promotion of change as opposed to stasis, illustrated by the recent revision of the Church emblem, the anchor of the first missionaries' ship, being replaced by three Mā'ohi trees (banana, breadfruit, and coconut). The anchor was seen as immobilizing the Church, as the Papetoai Head of Deacons, Ephraima Faatau, explains, "Maybe that was the reason why during this period of time, even when we decided to move on, we just stayed still" (Filmed interview with Epharaima Faatau 17 Feb. 2010).

Beyond Changes in the Communion: Discussions about Symbolism, Oration, Dress, and Dance

Not only was Papetoai the first local church to adopt the Mā'ohi communion, it is still notable for some of its other liturgical innovations. For example, it is the only church with dancing during the Lord's Supper service. Deacons and church members often explain such unique qualities of the church by referring to the pioneering role played by Papetoai in the evangelization of the Polynesian islands, recalling that the Papetoai temple was the first Gwendoline Malogne -Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, Christian stone building edified in the Pacific Islands [START_REF] Tauira | Mission chrétienne dans le Pacifique: le rôle des missionnaires Maohi (1821-1855)[END_REF]). Thus, they consider the liturgical innovations in line with a tradition of change. On the one hand, missionary, anthropological, and historical literatures rarely mention the contribution of Mā'ohi missionaries in the evangelization of the Pacific Islands. On the other hand, the local, oral history gives only a secondary role to the Western missionaries: there would have been no conversion to Christianity without the wind-God's instrument-that guided the missionary ship to Papetoai, or without the initiative of Pati'i, the great priest (tahu'a) of Papetoai (filmed interview with Punitai Teihotaata, orator of Papetoai, 4 March 2010)18. The history of the place also tells the story of Moorea's evangelization, and the composition of the Papetoai district includes a number of places that encapsulate memories of this historical event.

The emphasis put on the connection with the land in the liturgy has led to various levels of identification, as fenua designates the country, the island, the land, or a place. Congregational inclusion in the Church is expressed by three symbols-the coconut tree, the banana tree, and the breadfruit tree. This symbolism makes sense for most church members. Yet, parishioners can sometimes feel excluded when more specific places and symbols are used, as Alain Teheipuarii, the pastor in charge of the Haapiti church, remarks:

There are songs that the Papetoai church sings that you cannot sing anywhere else, for example, when they sing songs about Papetoai, the paripari fenua19. Most of these songs are from Papetoai and evoke water sources, a mountain, a lagoon pass, they often sing of things like that..., it's a way to praise God in relation to your place. But me, for example, I am not from there, I am from Raivavae; I can't praise the Lord through these songs, because they are songs specific to the inhabitants of Papetoai. (Interview, 2 feb. 2010)

Therefore, the emphasis that cultural renewal puts on territorial belonging can produce a sense of otherness and transform a close parishioner into a "stranger." The ministers who do not usually work in their parish of origin due to the system of pastoral posting are not the only ones able to identify fully with these paripari fenua. Individual mobility, from one island to another, is widespread in French Polynesia and lends particular importance to the mechanisms that help local churches to integrate newcomers from another village, and to welcome "friends passing

Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, through."20 Even some parishioners from Haapiti felt that their Papetoai neighbors treated them as tourists when they welcomed them with garlands of flowers at a joint service (garlands are seen as something designed for tourists and strangers, not for close neighbors).

The methods of cultural transmission are debated within the Papetoai church, as exemplified in the various practices of 'ōrero, a Polynesian oratorical art which is performed during the service. These 'ōrero are performed at the opening of the service by young boys and adolescents and express desires to strengthen youth participation in church life. However, using 'ōrero within the temple is contentious as it does not respect the traditional rules of public speech and the context that gives the 'ōrero its whole significance. Punitai Teihotaata, Papetoai orator and teacher of 'ōrero at the local primary school, explains why the 'ōrero should not have a place in the temple:

Let's talk about the 'ōrero now. Who declaims the 'ōrero? The 'ōrero should not be performed in a place where there is no visitor, no guest. It's when someone comes to meet someone else that the 'ōrero is to be declaimed. You don't perform an 'ōrero in the temple, because it's not a place for declamation, not a place to meet someone; it's a place where one speaks of the Bible so that people will be enlightened. There is only one occasion to perform the 'ōrero: when people meet, people from another land meeting people of this land.... To show your motherland: here, on my land, where to sit, to sleep, here is the place where I can sleep, here is my land. This is what the 'ōrero is about. There is nothing else to be found in the 'ōrero. It's through the meeting of people that the 'ōrero is to be elaborated. (filmed interview of 4 march 2010)

Papetoai is also one of the rare French Polynesian local churches that promote the wearing of the pareo even for church members. Yet, only a few wear a pareo during the Sunday service, and all of these are men (except one deacon's wife); no senior citizens, male or female, dare to wear it. Those who do wear it modestly cover their knees, and sometimes the pareo comes down to their ankles. A handful of parishioners wear long pants under their pareo, for fear that it may fall or split. Others hurry to their cars as soon as the service is finished to change their clothes. So wearing the pareo in the temple can generate a feeling of corporeal insecurity that seems to be linked with a sense of incongruity. How, then, can we explain its limited success? To wear the pareo in the temple negates the distinction between the private and public spheres, and it is inspired by the conviction that Mā'ohi cultural pride should be proclaimed in all domains of social life. Yet, this defiance fails to account for the historical reappropriation of "Western" Leiden & Boston,Brill, clothes by Polynesians and their shaping of local identities, a process described by Anna [START_REF] Paini | Rhabiller les symboles: les femmes kanak et la robe mission à Lifou (Nouvelle-Calédonie)[END_REF] with regard to the "Missionary dresses" in New Caledonia. It also underestimates the influence of tourism, which has fostered the reintroduction of the pareo in public places, while modifying the meaning of the garment. For example, tourist adverts displaying the pareo emphasise the exotic and erotic stereotypes associated with Polynesian women.

Finally, Papetoai is not just the only local church in French Polynesia where the congregation performs dances during the Lord's Supper service. It is in fact the only one where they may dance in the temple. Dance was introduced in the Papetoai temple in the early 2000s, at a time when the church had already lost half of its membership due to the Mā'ohi Communion. The deacons' committee took this decision based on biblical arguments, drawn from the reading of Psalms 149 and 150 21. They did not ask the opinion of parishioners but planned to explain their decision a posteriori, after the Sunday service. However, many parishioners were unhappy that they had not been consulted and chose to leave early, refusing to listen to any of the arguments put forward by the committee.

This introduction of dance into the temple provoked a second wave of departures. However, unlike in 1999, discontented church members did not leave the EPM or move to another local church. Most preferred to stay at home, listening to the Protestant radio station and organizing familial prayers (purera'a fēti'i). This example shows that when family can provide an alternative place of religious practice, disengagement from the church need not be linked with a secularization of social values. Instead, disengagement is a consequence of tensions within a local church characterised by a strong density of social relationships. Moreover, because these social relationships have a direct impact on their state of mind, some Paoetoai parishioners prefer to stay at home: "That's it," says Bruno Rupea's wife, "those who don't accept it stay at home, you see, sometimes I go with my husband, but I listen to the radio and it's better. There are all the songs, all the verses, the pastor who preaches, it's better, you listen, you're alone in your bedroom and you listen instead of going over there to the service and when you come back, you're upset. It's not worth it, it's better to pray to the Lord at home, you listen to the radio. I think people do that." (interview of 15 feb. 2010)

The introduction of dance in the temple radically breaks with the traditional rules organizing bodily attitudes during the service. Parishioners sit on the benches and stay quiet, without The movements in these dances are focused mainly on arms and hands (the dance known as the Aparima), and accompanied by songs praising the land and nature, and recitations of biblical verses. Couples' dances and overly suggestive movements-parted knees and jerky gesturesare not allowed. Thus, the freedom of movement is strongly bound and unequally available, depending on gender and age.

Despite these strict limitations, the introduction of dance into the temple has shocked many church members, even those who had accepted previous liturgical changes introduced in Papetoai. This process of cultural change implies two different levels of cultural engagement.

On the one hand, cultural renewal in the EPM leads to the inclusion of religious elements that are symbolic of Polynesian culture. The Mā'ohi Communion exemplifies this approach as it aims to honour Polynesian culture in the service, to foster the transmission of Polynesian culture and language to the younger generations, and to remove the dissociation between religious and everyday life. As missionary teaching contributed to disqualifying and banning some practices or aspects of the Polynesian culture, it has become the duty of the Church to struggle against this sense of guilt and "double conscience" resulting from missionary history.

On the other hand, through promotion of Polynesian practices like dance or the wearing of the pareo, cultural militancy goes beyond mere promotion of Polynesian culture, further including practices that missionaries once associated with paganism, considering their abandonment as a sign of Protestant conversion. [START_REF] Eves | Colonialism, Corporeality and Character: Methodist Missions and the Refashioning of Bodies in the Pacific[END_REF] has noted how Methodist missions in Papua New Guinea strongly associated the outer appearance (clothes, behaviors) with the inner moral state. These two levels of engagement correspond with different levels of Protestant belonging and practice. While some liturgical innovations do not necessarily entail active engagement by all

Gwendoline Malogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.), Christianity,Conflict and Renewal in Australia and the Pacific,Leiden & Boston,Brill, parishioners, other practices like the wearing of the pareo imply personal choices that are potentially in conflict with other social norms and familial obligations.

Conclusion

The engagement of the EPM with Polynesian practices in projects of cultural renewal has raised multiple issues concerning their methods, interpretation, and modes of participation in local church life. Since the Theological Commission developed its cultural agenda in 1980s-1990s, they have prompted the ongoing work of the reappropriation of tradition among the church clergy and members. They have also generated deep divisions between members. The recommendations of the Commission are still seen as additional, and for some, optional-for ministers who receive four-year training at the Theological School in Tahiti. Nevertheless, for some parishioners who have not assiduously attended the Sunday school, which provides a traditional Protestant education, the teachings of the Commission may be all they receive.

One of the main paradoxes of the Church's cultural and indigenous militancy is that it increases the gap between generations that it intended to fill. The EPM originally wanted to ensure that the Mā'ohi culture and tongue were passed down to the younger generation, in a context of widespread diffusion of the French language. However, because many of the youth of this generation have not perfectly mastered reo Mā'ohi, the Theological Commission excludes them from its work and from the reappropriation of the language in local churches. Instead, the older parishioners, who are more used to speaking reo Mā'ohi in the church and who made their living in agriculture and fishing, regard the teachings of the Commission as a tribute to their everyday work and to the "good old times." Even in the Austral islands, where they have not adopted the liturgical and theological changes, teachings of the Commission on the "return to the land" have led elders to regret that the younger generation are losing their traditional link with the land. Thus, the cultural militancy of the church intensifies debate about the increasing distance between excessively high cultural expectations and everyday lifestyles. Moreover, the message of the EPM remains paradoxically relevant, because it functions as a reminder of a nostalgic and demanding mode of cultural norms transformed into ideals that are difficult to reach.

  2007, as 70 per cent of the population declared they spoke in French in their family circle (insee Première 1230, March 2009, Recensement en Polynésie française 2007).

  GwendolineMalogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » inFiona MAGOWAN et Carolyn SCHWARZ (dir.),Christianity, Conflict and Renewal in Australia and the Pacific,

  GwendolineMalogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church(French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.),Christianity, Conflict and Renewal in Australia and the Pacific, Leiden & Boston, Brill, The pareo is associated with a time of life at home ... It's rather a conjugal thing, an intimate representation of the couple, it's almost a step towards the couple's love life. That's true, that's what it is, you wear the pareo on the beach, at home, you can't wear it anywhere. To wear a pareo tied in a specific way is a provocation in a...very intimate sense.(Interview with Matahi Hiro, retired army chaplain, 19 may 2001)

  GwendolineMalogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » inFiona MAGOWAN et Carolyn SCHWARZ (dir.),Christianity, Conflict and Renewal in Australia and the Pacific, Leiden & Boston, Brill,

Table ?

 ? That's how this stayed in my mind. And on Christmas Eve ... I prepared the unleavened bread; I made it with coconut milk. It smelled good, it's coconut bread without baking powder, I was the one who made the first one[...]. Those who preach and preach without practicing, as we say, that's why I didn't tell anyone[...]. At the deacons' committee [held after the service], I said, "I did it by faith, maybe the Holy Spirit led me to do that? Are you going to learn and meditate on the Word of God without practicing? It makes no sense." I did it by faith and through the guidance of the Holy Spirit, who led me to do that.(Interview with B. Rupea, 15 feb. 2010)

  GwendolineMalogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church (French Polynesia) » inFiona MAGOWAN et Carolyn SCHWARZ (dir.),Christianity, Conflict and Renewal in Australia and the Pacific,

  GwendolineMalogne-Fer, 2016. « A Dispute at the Lord's Supper: Theology and Culture in the Māohi Protestant Church(French Polynesia) » in Fiona MAGOWAN et Carolyn SCHWARZ (dir.),Christianity, Conflict and Renewal in Australia and the Pacific, Leiden & Boston, Brill, moving around, just looking ahead. Some local churches, as in neighboring Haapiti, go so far as to ban the hīmene tarava, traditional Polynesian songs accompanied by slight sideways movements of the upper body. Therefore, in Papetoai, the introduction of dance needs to be controlled and reshaped before it can become acceptable. In 2010, only three girls danced during the Lord's Supper service: a daughter of the head deacon, and the daughter and daughter-in-law of another deacon. Lisa Rupea, a 60-year-old deacon's wife, points to the gap between the "freedom" supposedly offered to everyone and the very few who can use it:Me, if I go dancing in the temple, people will say I am mad, but what do they pretend? If they can dance for the Lord, then I can dance too. And yet, people would treat me as a madwoman, even if I am dancing for the Lord!(interview, 15 feb. 2010)

The Heiva festival originally celebrated the French National Day (14th of July) and the inte-gration of French Polynesia into the French Republic.

"As well as being clothed, clean, neat and orderly, this body incorporated appropriate habits, comportments and gestures indicative of a disciplined Christian, whose interior morality was consistent with his or her outer body'"(Eves 1996, 86).

For a description of Polynesian clothing strategies at the beginning of the 19th century, see[START_REF] Ellis | [END_REF]Ellis, [1829]], 462.

In 1899, article 121 of the Church discipline stated that, "Members will be excluded from the Church who have been warned and excluded from communion for 3 to 6 months due to the following faults, if not amended: drunkards, players (games of chance), those who practice the upaupa dance."

In 1977, the Windward Islands, which include Tahiti and Moorea, comprised 73.8 per cent of the population.

While, in 1962, agriculture and fishing employed 46 per cent of the working population, these occupations only accounted for 14 per cent of the workforce by 1983. During the same period, the tertiary sector rose from 35 per cent to 64 per cent (ITSTAT, Institut territorialde la statistique, 1998, 137-138).

The establishment of the Center d'Expérimentations du Pacifique (CEP) in French Polynesia was a consequence of the political independence of Algeria(in 1962), where nuclear testing had formerly been conducted

The PTC was the first theological school to offer academic training (up to bachelor level) to Pacific ministers.

Pastor Gérard Bourges, head of the Protestant chaplaincy of French armies in French Polynesia, Ve'a porotetani,September 1989, 20-21.

See also Moorea d'Autrefois, edited by the association Te Ati Matahiapo Nui No Aimeho Nei, Editions Le Motu 2006, 100-103.

Paripari fenua are "traditional songs or discourses that tell the mythical origin of places they evoke"[START_REF] Lemaître | Lexique du Tahitien contemporain[END_REF].

For an analysis of mobility in Moorea, see Claude Robineau, 1984 Tradition et modernité aux îles Sous-le-Vent, livre I, Du coprah à l'atome,Paris, Orstom Editions (coll. Mémoires no. 100, 145).

Deacons had to use the French translation of the Bible, as the Tahitian version does not mention dance explicitly.


domain: phys sdv

text:
Olivia Peytral-Rieu

David Dubuc

Katia Grenier

RF sensor dedicated to the dielectric characterization of spheroids between 500 MHz and 20 GHz

Keywords: Biosensor, Microwave, Electromagnetic waves, Dielectric characterization, Coplanar waveguide (CPW), Label-free analysis, Spheroids, Cells

To achieve better accuracy in their investigations, biologists have recently been using threedimensional models as intermediates between 2D cell culture and the in vivo study of tissues. Some of these models are based on spheroids, which are cellular aggregates retaining many characteristics of in vivo behaviors while being still easy to use and implement in labs. To study such objects, multiples observation techniques can be used according to the objective of the study, including those using electromagnetic waves as non-destructive, non-invasive and label free analysis. Low frequencies (<1MHz) ones are currently under investigation as Electrochemical Impedance Spectroscopy. However, unlike microwaves (from 300MHz to 60GHz), they cannot penetrate the cell. Furthermore, most of the devices dedicated to microwave dielectric characterization are only focusing on cellular scales lower than spheroids (single cell, cell mats or suspensions) or on tissues and organs. In this article, a microwave spectroscopy device using a coplanar waveguide (CPW) adapted to the study of spheroids is presented with the dielectric characterization of fixed spheroids, with capacitance and conductance measurements from 0.5 to 20 GHz, aiming at filling the scale gap in the state of the art.

INTRODUCTION

As soon as cancers were discovered, it became clear to biologists that the use of in vitro models independently of in vivo analyses would be essential, given the complexity of the mechanisms involved in these diseases. 2D cell culture has been used extensively for its ease of manufacture and low cost. However, this type of model is far from the reality of in vivo systems. Therefore, 3D models of cell clusters in the form of spheres, also called spheroids, have been introduced as an intermediary between in vivo and 2D in vitro studies [START_REF] Nath | Three-dimensional culture systems in cancer research: Focus on tumor spheroid model[END_REF]. Indeed, spheroids are as easy and cheap to manufacture as 2D systems while having a complexity closer to physiological reality.

Numerous methods exist to analyse spheroids, the leading techniques being based on microscopy [START_REF] Costa | 3D tumor spheroids: an overview on the tools and techniques used for their analysis[END_REF], [START_REF] Santini | Three-Dimensional Spheroid Model in Tumor Biology[END_REF]. In addition, electrical approaches are being studied, with a particular interest for microsensors using the application of low-frequency electromagnetic waves [START_REF] Alexander | From Cellular Cultures to Cellular Spheroids: Is Impedance Spectroscopy a Viable Tool for Monitoring Multicellular Spheroid (MCS) Drug Models?[END_REF]- [START_REF] Gerasimenko | Impedance Spectroscopy as a Tool for Monitoring Performance in 3D Models of Epithelial Tissues[END_REF]. Indeed, they have the advantages of being non-invasive, non-destructive, label-free and affordable. For example, impedancemetry, using waves with a maximum frequency of 1 MHz, makes it possible to study molecular exchanges with the extracellular medium and at the cell membrane surroundings [START_REF] Pethig | The passive electrical properties of biological systems: their significance in physiology[END_REF].

Above a few hundred MHz, microwave dielectric spectroscopy involves the penetration of electromagnetic waves into cells through the cell membrane, opening up the possibility of analysing the intracellular content. Various devices exist to analyse cells in the microwave range, whether at the scale of the single cell, the cell suspension, the tissue or even the organ directly from the patient [START_REF] Tamra | Microwave dielectric spectroscopy for single cell irreversible electroporation monitoring[END_REF], [START_REF] Lazebnik | A large-scale study of the ultrawideband microwave dielectric properties of normal, benign and malignant breast tissues obtained from cancer surgeries[END_REF]. However, for the intermediate spheroids scale, there is no device that allows their analysis in this frequency range. Thus, this article presents a radio frequency (RF) device designed for the analysis of spheroids of 300μm in diameter in the frequency range of 500 MHz to 20 GHz.

First the equipment and methods used will be detailed, including a description of the biological objects tested, the manufacture of the microwave sensor and a reminder of the electrical model used for data analysis, since it is described in [START_REF] Peytral-Rieu | Microwave Sensor Dedicated to the Determination of the Dielectric Properties of 3D Biological Models from 500MHz to 20GHz[END_REF]. Then, the first dielectric characterization of a spheroid in the frequency range 0.5-20 GHz will be presented. Finally, a conclusion proposing future perspectives will be given.

MATERIALS & METHODS

Materials & reagents

Formaldehyde (used with formalin solution, neutral buffered, 10%) is purchased from Sigma-Aldrich (Saint-Quentin Fallavier, France). Gibco DMEM (high glucose, GlutaMAX supplement and pyruvate), fetal bovine serum (FBS) (HyClone), pen-strep solution (100X) (Gibco), 0.05% Trypsin-EDTA (HyClone), Gibco DPBS without Calcium, Magnesium (1X), Gibco Phosphate Buffered Saline 1X (PBS) and HEPES 1M (Gibco) are purchased from Thermo FisherScientific (Illkirch-Graffenstaden, France). The HepG2 cell line (catalog number HB8065) is purchased from the American Type Cell Collection (ATCC) (LGC Standards, Molsheim, France).

Cell culture

For our study, Human hepatoma cells (HepG2, passages 15-35) are cultured at 37°C/5% CO2 in DMEM medium complemented with 10% FBS and 1% pen-strep solution. Cells are grown up to 70-80% confluence.

HepG2 spheroids formation

The spheroids formation protocol is illustrated in Fig. 1. The method we have chosen to make the spheroids is to use a mold made by Sigma, called Micro Tissue 3D Petri Dish size S, which is a 16 x 16 (256) cell array, sized to fit in plates containing 12 wells. 1% agarose is poured into these molds, left to cool, unmolded and then placed in six-well plates. The immobilization of this network of 256 wells at the bottom of the wells is done with agarose. Balancing the pH of the agarose is then necessary to find conventional cell culture conditions before placing the cells. It is carried out by putting culture medium for 45 min with a change of medium every 15 min. After this step, the micro-molds are ready to receive the cells.

The adherent cells cultured in flasks are passed through trypsin for 5 min, before undergoing centrifugation to re-suspend them at the concentration of 20 000cells/190µL. The cell suspension is, then, deposited in the micro-molds. The whole is finally left in culture for three days to form spheroids of approximately 300 μm in diameter (see Figure 1 for a detailed diagram of the protocol).

The spheroids are retrieved with a P1000 micropipette after the three days of culture and deposited in an Eppendorf for fixation or for individualization in 96-well plates depending on the experiments planned. In both cases, the spheroids are, at this step, placed in DMEM culture medium containing no SVF but P/S and 25mM HEPES (to buffer the pH of the medium at room temperature) to stop their growth. Individualized, experiments can be done on then up to three days after recovery of the molds. The fixation of the spheroids is carried out after their recovery in pure formalin for 2.5 hours at room temperature.

The developed sensor

Architecture

Figure 2 shows the developed biosensor. The biosensor consists of two distinct parts. A dielectric spectroscopy detection part with a microwave circuit involving of a coplanar waveguide of gold 300 nm thick on quartz substrate, with a capacitive gap in the middle of the structure on the central conductor (cf. Figure 2). Specifically, the RF accesses are implemented with a coplanar waveguide with a central conductor width of 130 µm, separated from the side grounds by a slot of 14 µm (cf. Figure 2 a). This coplanar configuration allows the placement of radio frequency (RF) GSG coplanar probes for characterization. The sensing area corresponds to the 10 µm wide capacitive gap in the centre of the structure and the central conductor, as visible in Figure 2 b).

A fluidic part, which includes a fluidic channel and a micro-tank and two lateral reservoirs. The geometry of this channel allows it to hold 30 µL of host medium (see Figure 2 d). This configuration is open, i.e. without a cover over the channel and reservoirs. The spheroid is then manually positioned

Device micro-fabrication

The fabrication of the biosensor is composed of two main steps based on classical microfabrication processes resumed in the Figure 3.

The electromagnetic sensor is fabricated on a quartz wafer (Corning Eagle XG series) previously cleaned by two minutes in a piranha mixture (50/50v sulphuric acid H2SO4 hydrogen peroxide H2O2) followed by an oxygen plasma for fifteen minutes. The metallization is carried out using the lift-off technique. Indeed, a first photolithography of negative NLOF resin of 2.5 µm thickness is carried out to define the structure of the biosensor, then a metallization by evaporation of Titanium (Ti)/Gold (Au) is carried out. After metallization, a lift off in acetone for about one hour allows to remove the gold adhering to the NLOF photoresist and to obtain only the gold forming the desired structure. The waveguide obtained is composed of a thin layer of Ti, helping the adhesion of a metal on the substrate, followed by a 300 nm thick Au deposit. Figure 2 c) presents the obtained device. The second and final step corresponds to the elaboration of the fluidic walls and the two reservoirs placed on either side of the biosensor with a 500 µm thick SU8-3050 layer deposited by gravity and then exposed and developed [START_REF] Peytral-Rieu | Microwave Sensor Dedicated to the Determination of the Dielectric Properties of 3D Biological Models from 500MHz to 20GHz[END_REF], [START_REF] Peytral-Rieu | Microwave Microfabricated Sensor Dedicated to the Dielectric Characterization of Biological Microtissues[END_REF]. The gravity method consists of manually depositing 6g of SU8-3050 photoresist on the wafer, followed by a bake with a slow temperature ramp up to 95°C (then levelling off for 11h and naturally descending to room temperature) before carrying out the exposure at 365 nm with an energy of 3.6 J/cm², followed by the post exposure bake (with temperature ramp up to 95°C and a one hour plateau) and finally the development for about 45min. Figure 2 d) and e) present the obtained device.

MODELLING AND EXPERIMENTAL PROTOCOL

The characterization of microwave components requires prior calibration of the two-port vector network analyser (VNA). A SOLT (Short, Open, Load, Thru) type calibration is performed with a Cascade Microtech calibration kit.

The test bench is presented in Figure 4 a). The probe station, shown on the right of Figure 4 a), is positioned on an anti-vibration table with the VNA at the rear. The positioning of the probes and the general control of the micro-device is done by means of an upright microscope, whose image is transcribed by a camera on a screen placed on the VNA.

After this calibration step, the device is connected to the VNA with two coplanar probes and cables. A first measurement of the 𝑆 parameters is carried out while the sensor is unloaded. It allows to obtain the first measurement, which is necessary afterwards for data analysis, as developed in [START_REF] Peytral-Rieu | Microwave Sensor Dedicated to the Determination of the Dielectric Properties of 3D Biological Models from 500MHz to 20GHz[END_REF]. Next, the host medium alone is loaded into the device and measurements of the 𝑆 parameters are performed for 25 min to check the measurement stability of the device before loading a biological object. The filling of the device is done by depositing 15μL of the host medium, PBS in our case, in each of the reservoirs and checking that no bubble forms on the detection area. Finally, the tested object available in culture medium is loaded into the middle tank. Just before manually positioning the object under study on the sensing zone using a micropipette, a measurement of the parameters 𝑆 of the PBS host medium is performed. This measurement serves as a reference (giving 𝐶 𝑟𝑒𝑓 and 𝐺 𝑟𝑒𝑓 ). Measurements of the 𝑆 parameters of the spheroid (or of the polystyrene beads) are then carried out for 20min to extract its dielectric parameters.

5µm NLOF resin. Ti/Au metal layer (50/300nm). d) Results obtained after a lift off of about one hour in an acetone bath. e) Results obtained after a lift off of about one hour in an acetone bath. f) Results obtained after a lift off of about one hour in an acetone bath. g) Results obtained after a lift off of about one hour in an acetone bath. e) Gravitational deposition of a thick layer of SU8. f) Fluid walls obtained after exposure and development of the SU8.

In a few words, the data analysis is based on an electrical model allowing us to extract a capacitance 𝐶 and a conductance 𝐺 of the device under test (DUT). With a contrast method using a reference measurement, 𝐶 𝑟𝑒𝑓 and 𝐺 𝑟𝑒𝑓 , the specific influence of the studied object can be decorrelated from the culture medium in the form of ∆𝐶 and a ∆𝐺 calculated with equations ( 1) and ( 2) respectively. The raw data, CDUT, GDUT, Cref and Gref , and the standard deviations of the contrasts are given in [START_REF] Peytral-Rieu | Microwave Microfabricated Sensor Dedicated to the Dielectric Characterization of Biological Microtissues[END_REF] and [START_REF] Peytral-Rieu | Microwave Sensor Dedicated to the Determination of the Dielectric Properties of 3D Biological Models from 500MHz to 20GHz[END_REF] respectively.

∆𝐶 = 𝐶 𝐷𝑈𝑇 -𝐶 𝑟𝑒𝑓 (1)
∆𝐺 = 𝐺 𝐷𝑈𝑇 -𝐺 𝑟𝑒𝑓 (2)

RESULTS

In order to evaluate the stability of liquid measurements with our sensor, especially due to the open fluidic configuration, all PBS host medium measurements realized with different sensors and setup calibrations have been pooled and are presented in Figure 4 d) and e). The blue curve corresponds to the average response of PBS measurements. It is defined by taking the average response of each independent PBS measurements into account. Those ones are previously obtained by averaging the 25 measurements of a PBS solution achieved every minute during 24 minutes, while their reference corresponds to the first PBS measurement realized after the stabilization procedure done within the sensor. The capacitive and conductive contrasts obtained with PBS shown in Figure 4 d) and e) are extremely close to the zero level. Maximum deviations of -1.39 fF and -0.02 mS in absolute value are obtained, which demonstrate the high robustness and repeatability of the microwave measurements of this sensor.

Next, to validate the micro-device and its proper functioning, two polystyrene beads are first measured and then three spheroids fixed with Formalin are measured every minute for 25 min. Their capacitive and conductive contrasts in mean value over the measurement period are shown in Figure 4 d) and e). The used reference is a PBS measurement realized just before the microwave characterization of each individual sample (bead or spheroid). The responses obtained for the beads are represented by the curves in purple, while those of the spheroids are in green and orange respectively.

A large variation between the dielectric responses acquired for the reference liquid (PBS) and the beads is obtained and may be easily explained by the fact that the beads present a low permittivity close to 3, whereas the PBS reference liquid exhibits a permittivity close to the one of water, i.e. frequency dependent and around to 80 at 5 GHz. The extracted capacitive contrasts of polystyrene beads are located below -60 fF around 2 GHz, while the conductive contrasts at 20 GHz are close to -10 mS.

As far as the fixed spheroids are concerned, their capacitive and conductive contrasts are lower in absolute value compare to the polystyrene bead. The capacitive and the conductive contrasts of the fixed spheroids are indeed smaller than 20 fF around 2GHz and 2,5mS at 20GHz in absolute value respectively. These results are consistent since the permittivity of a spheroid is close to the reference liquid, PBS. This is all the more true that the spheroid has been fixed with formaldehyde, a treatment that causes permeabilization of the cell membrane. Thus, when stored in PBS, an equilibrium between the intra-and extra-cellular media happens, which decreases the dielectric contrasts in absolute value [START_REF] Artis | Microwaving Biological Cells: Intracellular Analysis with Microwave Dielectric Spectroscopy[END_REF], [START_REF] Chan | The effect of cell fixation on the discrimination of normal and leukemia cells with laser tweezers Raman spectroscopy[END_REF]. Under these conditions, the measured contrasts are therefore lower in absolute value than for a living spheroid, allowing a proof of concept with a biological object that is easier to manipulate but more difficult to detect. Such fixed spheroids are indeed easier to prepare, may be stored for weeks, and used at convenience for experiments.

Finally, each spheroid presents a specific response, notably due to differences in shape and size. Indeed, despite a method that allows the creation of many spheroids in a short time, it is difficult to obtain perfectly round spheroids having exactly the same diameter.

CONCLUSIONS

This article presents the first device allowing the dielectric characterization of spheroids and developed with its associated electrical model and characterized using first polystyrene beads and then formalin-fixed spheroids. The detailed protocol for the fabrication of the spheroids is also presented. The dielectric characterization results obtained are particularly promising for the use of microwave dielectric spectroscopy for the study of spheroids, since they allow the spheroids to be distinguished from each other despite the fact that they have undergone fixation, which induces very weak but nevertheless significantly observable capacitive and conductive contrasts with the host medium. These results show the feasibility of measuring spheroids in their culture medium by microwave dielectric spectroscopy, which had never been done before. The results of the measurement of polystyrene

Figure 1 :

 1 Figure 1: Experimental protocol for the manufacture of tumor spheroids

Figure 2 :

 2 Figure 2: a) and b) Detailed diagram of the RF device with the schematic of a spheroid at its center in pink. a) Global view; W = Signal; S = Slit; G = Ground. b) Zoom in on the central part of the sensor with the dimensions of the electrodes and the capacitive gap. c), d) and e) Pictures taken with an HIROX microscope. c) Picture of the device only with the first metallization. d) Picture of the device after the second microfabrication step: the fluidic wall. e) Global picture of the microdevice.

Figure 3 :

 3 Figure 3: Diagram of the microfabrication of the biosensor. In pink, the representation of the photosensitive resin, in yellow the gold conductive layer, in brown the titanium layer allowing the adhesion to the quartz substrate. Finally, in green, the thickness of the SU 8 polymer. a) First cleaning step of the wafer. b) Result of the deposition and exposure of the 2.5µm NLOF resin. Ti/Au metal layer (50/300nm). d) Results obtained after a lift off of about one hour in an acetone bath. e) Results obtained after a lift off of about one hour in an acetone bath. f) Results obtained after a lift off of about one hour in an acetone bath. g) Results obtained after a lift off of about one hour in an acetone bath. e) Gravitational deposition of a thick layer of SU8. f) Fluid walls obtained after exposure and development of the SU8.

Figure 4 :

 4 Figure 4: a) Presentation photo of the microwave test bench with the different elements. b) and c) Pictures of the device loaded with a spheroid and a polystyrene bead respectively. d) and e) Capacitive contrast ΔC and conductive contrast ΔG spectra obtained with the reference fluid in blue (PBS), polystyrene beads in green and fixed spheroid in red, purple and beige, respectively. The curves represent the average of measurements made over 25 minutes.

ACKNOWLEDGEMENTS

This work was partly supported by LAAS-CNRS micro and nanotechnologies platform member of the French RENATECH network.