Université PSL

Publications

RECHERCHER

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VEGF (Vascular Endothelial Growth Factor) Functionalized Magnetic Beads in a Microfluidic Device to Improve the Angiogenic Balance in Preeclampsia
Laboratoire Synthèse Electrochimie Imagerie et Systèmes Analytiques - Laura Trapiella-Alfonso, Lucile Alexandre, Camille Fraichard, Kelly Pons, Simon Dumas, Lucie Huart, Jean-François Gaucher, Marylise Hebert-Schuster, Jean Guibourdenche, Thierry Fournier, Michel Vidal, Isabelle Broutin
Hypertension - 74 145-153 - DOI: 10.1007/978-1-4939-9516-5_23 - 2019
Preeclampsia is a hypertensive pregnancy disease associated with a massive increase in sFlt-1 (soluble form of the vascular endothelial growth factor 1) in the maternal circulation, responsible for angiogenic imbalance and endothelial dysfunction. Pilot studies suggest that extracorporeal apheresis may reduce circulating sFlt-1 and prolong pregnancy. Nonspecific apheresis systems have potential adverse effects because of the capture of many other molecules. Our concept is based on a specific and competitive apheresis approach using VEGF (vascular endothelial growth factor) functionalized magnetic beads to capture sFlt-1 while releasing endogenous PlGF (placental growth factor) to restore a physiological angiogenic balance. Magnetic beads were functionalized with VEGF to capture sFlt-1. Experiments were performed using PBS, conditioned media from human trophoblastic cells, and human plasma. The proof of concept was validated in dynamic conditions in a microfluidic device as an approach mimicking real apheresis. Magnetic beads were functionalized with VEGF and characterized to evaluate their surface ligand density and recognition capabilities. VEGF-coated magnetic beads proved to be an efficient support in capturing sFlt-1 and releasing PlGF. In static conditions, sFlt-1 concentration decreased by 33±13%, whereas PlGF concentration increased by 27±10%. In dynamic conditions, the performances were improved, with 40% reduction of sFlt-1 and up to 2-fold increase of free PlGF. The sFlt-1/PlGF ratio was reduced by 63% in the plasma of preeclamptic patients. Apheresis was also associated with VEGF release. A ligand-based approach using VEGF-coated beads is an effective approach to the capture of sFlt-1 and the release of endogenous PlGF. It offers new perspectives for the treatment of preeclampsia.
Sign epistasis caused by hierarchy within signalling cascades.
Laboratoire Biochimie - Nghe P, Kogenaru M, Tans SJ.
Nat Commun - 9(1) 1451. - doi: 10.1038/s41467-018-03644-8 - 2018
Sign epistasis is a central evolutionary constraint, but its causal factors remain difficult to predict. Here we use the notion of parameterised optima to explain epistasis within a signalling cascade, and test these predictions in Escherichia coli. We show that sign epistasis arises from the benefit of tuning phenotypic parameters of cascade genes with respect to each other, rather than from their complex and incompletely known genetic bases. Specifically, sign epistasis requires only that the optimal phenotypic parameters of one gene depend on the phenotypic parameters of another, independent of other details, such as activating or repressing nature, position within the cascade, intra-genic pleiotropy or genotype. Mutational effects change sign more readily in downstream genes, indicating that optimising downstream genes is more constrained. The findings show that sign epistasis results from the inherent upstream-downstream hierarchy between signalling cascade genes, and can be addressed without exhaustive genotypic mapping.
Coupled catabolism and anabolism in autocatalytic RNA sets.
Laboratoire Biochimie - Arsène S, Ameta S, Lehman N, Griffiths AD, Nghe P.
Nucleic Acids Res. - 46(18) 9660-9666 - doi: 10.1093/nar/gky598. - 2018
The ability to process molecules available in the environment into useable building blocks characterizes catabolism in contemporary cells and was probably critical for the initiation of life. Here we show that a catabolic process in collectively autocatalytic sets of RNAs allows diversified substrates to be assimilated. We modify fragments of the Azoarcus group I intron and find that the system is able to restore the original native fragments by a multi-step reaction pathway. This allows in turn the formation of catalysts by an anabolic process, eventually leading to the accumulation of ribozymes. These results demonstrate that rudimentary self-reproducing RNA systems based on recombination possess an inherent capacity to assimilate an expanded repertoire of chemical resources and suggest that coupled catabolism and anabolism could have arisen at a very early stage in primordial living systems.
Selection Dynamics in Transient Compartmentalization.
Laboratoire Biochimie - Blokhuis A, Lacoste D, Nghe P, Peliti L
Phys. Rev. Lett. - 158101 120(15): - doi: 10.1371/journal.pcbi.1004972 - 2018
Transient compartments have been recently shown to be able to maintain functional replicators in the context of prebiotic studies. Here, we show that a broad class of selection dynamics is able to achieve this goal. We identify two key parameters, the relative amplification of nonactive replicators (parasites) and the size of compartments. These parameters account for competition and diversity, and the results are relevant to similar multilevel selection problems, such as those found in virus-host ecology and trait group selection.
Selection Dynamics in Transient Compartmentalization
Laboratoire Biochimie - doi.org/10.1103/PhysRevLett.120.158101
Phys. Rev. Lett. - 120 158101 - doi.org/10.1103/PhysRevLett.120.158101 - 2018
Transient compartments have been recently shown to be able to maintain functional replicators in the context of prebiotic studies. Here, we show that a broad class of selection dynamics is able to achieve this goal. We identify two key parameters, the relative amplification of nonactive replicators (parasites) and the size of compartments. These parameters account for competition and diversity, and the results are relevant to similar multilevel selection problems, such as those found in virus-host ecology and trait group selection.
Spontaneous migration of cellular aggregates from giant keratocytes to running spheroids.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Grégory Beaune, Carles Blanch-Mercader, Stéphane Douezan, Julien Dumond, David Gonzalez-Rodriguez, Damien Cuvelier, Thierry Ondarçuhu, Pierre Sens, Sylvie Dufour, Michael P Murrell, Françoise Brochard-Wyart
Proceedings of the National Academy of Sciences of the United States of America - 12926-12931 - 10.1073/pnas.1811348115 - 2018
Despite extensive knowledge on the mechanisms that drive single-cell migration, those governing the migration of cell clusters, as occurring during embryonic development and cancer metastasis, remain poorly understood. Here, we investigate the collective migration of cell on adhesive gels with variable rigidity, using 3D cellular aggregates as a model system. After initial adhesion to the substrate, aggregates spread by expanding outward a cell monolayer, whose dynamics is optimal in a narrow range of rigidities. Fast expansion gives rise to the accumulation of mechanical tension that leads to the rupture of cell-cell contacts and the nucleation of holes within the monolayer, which becomes unstable and undergoes dewetting like a liquid film. This leads to a symmetry breaking and causes the entire aggregate to move as a single entity. Varying the substrate rigidity modulates the extent of dewetting and induces different modes of aggregate motion: « giant keratocytes, » where the lamellipodium is a cell monolayer that expands at the front and retracts at the back; « penguins, » characterized by bipedal locomotion; and « running spheroids, » for nonspreading aggregates. We characterize these diverse modes of collective migration by quantifying the flows and forces that drive them, and we unveil the fundamental physical principles that govern these behaviors, which underscore the biological predisposition of living material to migrate, independent of length scale.
Innate Immune Signals Induce Anterograde Endosome Transport Promoting MHC Class I Cross-Presentation.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Weimershaus M, Mauvais FX, Saveanu L, Adiko C, Babdor J, Abramova A, Montealegre S, Lawand M, Evnouchidou I, Huber KJ, Chadt A, Zwick M, Vargas P, Dussiot M, Lennon-Dumenil AM, Brocker T, Al-Hasani H, van Endert P.
Cell Reports - 24(13) 3568-3581 - doi: 10.1016/j.celrep.2018.08.041 - 2018
Both cross-presentation of antigens by dendritic cells, a key pathway triggering T cell immunity and immune tolerance, and survival of several pathogens residing in intracellular vacuoles are intimately linked to delayed maturation of vesicles containing internalized antigens and microbes. However, how early endosome or phagosome identity is maintained is incompletely understood. We show that Toll-like receptor 4 (TLR4) and Fc receptor ligation induces interaction of the GTPase Rab14 with the kinesin KIF16b mediating plus-end-directed microtubule transport of endosomes. As a result, Rab14 recruitment to phagosomes delays their maturation and killing of an internalized pathogen. Enhancing anterograde transport by overexpressing Rab14, promoting the GTP-bound Rab14 state, or inhibiting retrograde transport upregulates cross-presentation. Conversely, reducing Rab14 expression, destabilizing Rab14 endosomes, and inhibiting anterograde microtubule transport by Kif16b knockdown compromise cross-presentation. Therefore, regulation of early endosome trafficking by innate immune signals is a critical parameter in cross-presentation by dendritic cells.
Diversification of human plasmacytoid predendritic cells in response to a single stimulus
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Alculumbre SG, Saint-André V1, Di Domizio J, Vargas P, Sirven P, Bost P, Maurin M, Maiuri P, Wery M, Roman MS, Savey L, Touzot M, Terrier B, Saadoun D, Conrad C, Gilliet M, Morillon A, Soumelis V.
Nat Immunol. - 19(1) 63-75 - doi: 10.1038/s41590-017-0012-z - 2018
Innate immune cells adjust to microbial and inflammatory stimuli through a process termed environmental plasticity, which links a given individual stimulus to a unique activated state. Here, we report that activation of human plasmacytoid predendritic cells (pDCs) with a single microbial or cytokine stimulus triggers cell diversification into three stable subpopulations (P1-P3). P1-pDCs (PD-L1+CD80-) displayed a plasmacytoid morphology and specialization for type I interferon production. P3-pDCs (PD-L1-CD80+) adopted a dendritic morphology and adaptive immune functions. P2-pDCs (PD-L1+CD80+) displayed both innate and adaptive functions. Each subpopulation expressed a specific coding- and long-noncoding-RNA signature and was stable after secondary stimulation. P1-pDCs were detected in samples from patients with lupus or psoriasis. pDC diversification was independent of cell divisions or preexisting heterogeneity within steady-state pDCs but was controlled by a TNF autocrine and/or paracrine communication loop. Our findings reveal a novel mechanism for diversity and division of labor in innate immune cells.
Spontaneous migration of cellular aggregates from giant keratocytes to running spheroids
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Grégory Beaune, Carles Blanch-Mercader, Stéphane Douezan, Julien Dumond, David Gonzalez-Rodriguez, Damien Cuvelier, Thierry Ondarçuhu, Pierre Sens, Sylvie Dufour, Michael P. Murrell, and Françoise Brochard-Wyart
Cell Sci - 115 (51) 12926-12931 - doi.org/10.1073/pnas.1811348115 - 2018
Despite extensive knowledge on the mechanisms that drive single-cell migration, those governing the migration of cell clusters, as occurring during embryonic development and cancer metastasis, remain poorly understood. Here, we investigate the collective migration of cell on adhesive gels with variable rigidity, using 3D cellular aggregates as a model system. After initial adhesion to the substrate, aggregates spread by expanding outward a cell monolayer, whose dynamics is optimal in a narrow range of rigidities. Fast expansion gives rise to the accumulation of mechanical tension that leads to the rupture of cell–cell contacts and the nucleation of holes within the monolayer, which becomes unstable and undergoes dewetting like a liquid film. This leads to a symmetry breaking and causes the entire aggregate to move as a single entity. Varying the substrate rigidity modulates the extent of dewetting and induces different modes of aggregate motion: “giant keratocytes,” where the lamellipodium is a cell monolayer that expands at the front and retracts at the back; “penguins,” characterized by bipedal locomotion; and “running spheroids,” for nonspreading aggregates. We characterize these diverse modes of collective migration by quantifying the flows and forces that drive them, and we unveil the fundamental physical principles that govern these behaviors, which underscore the biological predisposition of living material to migrate, independent of length scale.
Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Arthur Charles-Orszag, Feng-Ching Tsai, Daria Bonazzi, Valeria Manriquez, Martin Sachse, Adeline Mallet, Audrey Salles, Keira Melican, Ralitza Staneva, Aurélie Bertin, Corinne Millien, Sylvie Goussard, Pierre Lafaye, Spencer Shorte, Matthieu Piel, Jacomi
Nature Communications - 185.41666667 - Adhesion to nanofibers drives cell membrane remodeling through one-dimensional wetting. - 2018
The shape of cellular membranes is highly regulated by a set of conserved mechanisms that can be manipulated by bacterial pathogens to infect cells. Remodeling of the plasma membrane of endothelial cells by the bacterium Neisseria meningitidis is thought to be essential during the blood phase of meningococcal infection, but the underlying mechanisms are unclear. Here we show that plasma membrane remodeling occurs independently of F-actin, along meningococcal type IV pili fibers, by a physical mechanism that we term ‘one-dimensional’ membrane wetting. We provide a theoretical model that describes the physical basis of one-dimensional wetting and show that this mechanism occurs in model membranes interacting with nanofibers, and in human cells interacting with extracellular matrix meshworks. We propose one-dimensional wetting as a new general principle driving the interaction of cells with their environment at the nanoscale that is diverted by meningococci during infection.
Size control in mammalian cells involves modulation of both growth rate and cell cycle duration.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Article | OPEN | Published: 16 August 2018 Size control in mammalian cells involves modulation of both growth rate and cell cycle duration Clotilde Cadart, Sylvain Monnier, Jacopo Grilli, Pablo J. Sáez, Nishit Srivastava, Rafaele Attia, Emmanuel Terriac
Nature Communications - 9 3275 - DOI : 10.1038/s41467-018-05393-0 - 2018
Despite decades of research, how mammalian cell size is controlled remains unclear because of the difficulty of directly measuring growth at the single-cell level. Here we report direct measurements of single-cell volumes over entire cell cycles on various mammalian cell lines and primary human cells. We find that, in a majority of cell types, the volume added across the cell cycle shows little or no correlation to cell birth size, a homeostatic behavior called “adder”. This behavior involves modulation of G1 or S-G2 duration and modulation of growth rate. The precise combination of these mechanisms depends on the cell type and the growth condition. We have developed a mathematical framework to compare size homeostasis in datasets ranging from bacteria to mammalian cells. This reveals that a near-adder behavior is the most common type of size control and highlights the importance of growth rate modulation to size control in mammalian cells.
LINC complex-Lis1 interplay controls MT1-MMP matrix digest-on-demand response for confined tumor cell migration.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Elvira Infante, Alessia Castagnino, Robin Ferrari, Pedro Monteiro, Sonia Agüera-González, Perrine Paul-Gilloteaux, Mélanie J Domingues, Paolo Maiuri, Matthew Raab, Catherine M Shanahan, Alexandre Baffet, Matthieu Piel, Edgar R Gomes, Philippe Chavrier
Nature Communications - 9 2443 - DOI : 10.1038/s41467-018-04865-7 - 2018
Cancer cells’ ability to migrate through constricting pores in the tissue matrix is limited by nuclear stiffness. MT1-MMP contributes to metastasis by widening matrix pores, facilitating confined migration. Here, we show that modulation of matrix pore size or of lamin A expression known to modulate nuclear stiffness directly impinges on levels of MT1-MMP-mediated pericellular collagenolysis by cancer cells. A component of this adaptive response is the centrosome-centered distribution of MT1-MMP intracellular storage compartments ahead of the nucleus. We further show that this response, including invadopodia formation in association with confining matrix fibrils, requires an intact connection between the nucleus and the centrosome via the linker of nucleoskeleton and cytoskeleton (LINC) complex protein nesprin-2 and dynein adaptor Lis1. Our results uncover a digest-on-demand strategy for nuclear translocation through constricted spaces whereby confined migration triggers polarization of MT1-MMP storage compartments and matrix proteolysis in front of the nucleus depending on nucleus-microtubule linkage.
Role of calcium permeable channels in dendritic cell migration.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Sáez PJ, Sáez JC, Lennon-Duménil AM, Vargas P.
Curr Opin Immunol. - 52 74-80 - doi: 10.1016/j.coi.2018.04 - 2018
Calcium ion (Ca2+) is an essential second messenger involved in multiple cellular and subcellular processes. Ca2+ can be released and sensed globally or locally within cells, providing complex signals of variable amplitudes and time-scales. The key function of Ca2+ in the regulation of acto-myosin contractility has provided a simple explanation for its role in the regulation of immune cell migration. However, many questions remain, including the identity of the Ca2+ stores, channels and upstream signals involved in this process. Here, we focus on dendritic cells (DCs), because their immune sentinel function heavily relies on their capacity to migrate within tissues and later on between tissues and lymphoid organs. Deciphering the mechanisms by which cytoplasmic Ca2+ regulate DC migration should shed light on their role in initiating and tuning immune responses.
Mixed Copolymer Adlayers Allowing Reversible Thermal Control of Single Cell Aspect Ratio.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Dalier F, Dubacheva GV, Coniel M, Zanchi D, Galtayries A, Piel M, Marie E, Tribet C.
ACS Appl Mater Interfaces - 10(3) 2253-2258 - doi: 10.1021/acsami.7b18513. - 2018
Dynamic guidance of living cells is achieved by fine-tuning and spatiotemporal modulation on artificial polymer layers enabling reversible peptide display. Adjustment of surface composition and interactions is obtained by coadsorption of mixed poly(lysine) derivatives, grafted with either repellent PEG, RGD adhesion peptides, or T-responsive poly(N-isopropylacrylamide) strands. Deposition of mixed adlayers provides a straightforward mean to optimize complex substrates, which is here implemented to achieve (1) thermal control of ligand accessibility and (2) adjustment of relative adhesiveness between adjacent micropatterns, while preserving cell attachment during thermal cycles. The reversible polarization of HeLa cells along orthogonal stripes mimics guidance along natural matrices.
Retraction Notice to: FMN2 Makes Perinuclear Actin to Protect Nuclei during Confined Migration and Promote Metastasis.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Skau CT, Fischer RS, Gurel P, Thiam HR, Tubbs A, Baird MA, Davidson MW, Piel M, Alushin GM, Nussenzweig A, Steeg PS, Waterman CM.
Cell - 173(2) 529 - doi: 10.1016/j.cell.2018.03.058 - 2018
FMN2 Makes Perinuclear Actin to Protect Nuclei during Confined Migration and Promote Metastasis. [Cell. 2016]
Leukocyte Migration and Deformation in Collagen Gels and Microfabricated Constrictions
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Sáez PJ, Barbier L, Attia R, Thiam HR, Piel M, Vargas P.
Methods Mol Biol. - 1749 361-373 - doi: 10.1007/978-1-4939-7701-7_26. - 2018
In multicellular organisms, cell migration is a complex process. Examples of this are observed during cell motility in the interstitial space, full of extracellular matrix fibers, or when cells pass through endothelial layers to colonize or exit specific tissues. A common parameter for both situations is the fast adaptation of the cellular shape to their irregular landscape. In this chapter, we describe two methods to study cell migration in complex environments. The first one consists in a multichamber device for the visualization of cell haptotaxis toward the collagen-binding chemokine CCL21. This method is used to study cell migration as well as deformations during directed motility, as in the interstitial space. The second one consists in microfabricated channels connected to small constrictions. This procedure allows the study of cell deformations when single cells migrate through small holes and it is analogous to passage of cells through endothelial layers, resulting in a simplified system to study the mechanisms operating during transvasation. Both methods combined provide a powerful hub for the study of cell plasticity during migration in complex environments.
Leukocyte Migration and Deformation in Collagen Gels and Microfabricated Constrictions.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Sáez PJ, Barbier L, Attia R, Thiam HR, Piel M, Vargas P
Methods Mol Biol. - 1749 361-373 - doi: 10.1007/978-1-4939-7701-7_26 - 2018
In multicellular organisms, cell migration is a complex process. Examples of this are observed during cell motility in the interstitial space, full of extracellular matrix fibers, or when cells pass through endothelial layers to colonize or exit specific tissues. A common parameter for both situations is the fast adaptation of the cellular shape to their irregular landscape. In this chapter, we describe two methods to study cell migration in complex environments. The first one consists in a multichamber device for the visualization of cell haptotaxis toward the collagen-binding chemokine CCL21. This method is used to study cell migration as well as deformations during directed motility, as in the interstitial space. The second one consists in microfabricated channels connected to small constrictions. This procedure allows the study of cell deformations when single cells migrate through small holes and it is analogous to passage of cells through endothelial layers, resulting in a simplified system to study the mechanisms operating during transvasation. Both methods combined provide a powerful hub for the study of cell plasticity during migration in complex environments.
Mixed Copolymer Adlayers Allowing Reversible Thermal Control of Single Cell Aspect Ratio.
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Dalier F1, Dubacheva GV1, Coniel M1, Zanchi D1,2, Galtayries A, Piel M, Marie E1, Tribet C1.
ACS Appl Mater Interfaces - 10(3) 2253-2258 - doi: 10.1021/acsami.7b18513. - 2018
Dynamic guidance of living cells is achieved by fine-tuning and spatiotemporal modulation on artificial polymer layers enabling reversible peptide display. Adjustment of surface composition and interactions is obtained by coadsorption of mixed poly(lysine) derivatives, grafted with either repellent PEG, RGD adhesion peptides, or T-responsive poly(N-isopropylacrylamide) strands. Deposition of mixed adlayers provides a straightforward mean to optimize complex substrates, which is here implemented to achieve (1) thermal control of ligand accessibility and (2) adjustment of relative adhesiveness between adjacent micropatterns, while preserving cell attachment during thermal cycles. The reversible polarization of HeLa cells along orthogonal stripes mimics guidance along natural matrices.
Diversification of human plasmacytoid predendritic cells in response to a single stimulus
Laboratoire Biologie cellulaire systémique de la polarité et de la division - Alculumbre SG, Saint-André V, Di Domizio J, Vargas P, Sirven P, Bost P, Maurin M, Maiuri P, Wery M, Roman MS, Savey L, Touzot M, Terrier B, Saadoun D, Conrad C, Gilliet M, Morillon A, Soumelis V
Nat Immunol. - 19(1) 63-75 - doi: 10.1038/s41590-017-0012-z. - 2018
Innate immune cells adjust to microbial and inflammatory stimuli through a process termed environmental plasticity, which links a given individual stimulus to a unique activated state. Here, we report that activation of human plasmacytoid predendritic cells (pDCs) with a single microbial or cytokine stimulus triggers cell diversification into three stable subpopulations (P1-P3). P1-pDCs (PD-L1+CD80-) displayed a plasmacytoid morphology and specialization for type I interferon production. P3-pDCs (PD-L1-CD80+) adopted a dendritic morphology and adaptive immune functions. P2-pDCs (PD-L1+CD80+) displayed both innate and adaptive functions. Each subpopulation expressed a specific coding- and long-noncoding-RNA signature and was stable after secondary stimulation. P1-pDCs were detected in samples from patients with lupus or psoriasis. pDC diversification was independent of cell divisions or preexisting heterogeneity within steady-state pDCs but was controlled by a TNF autocrine and/or paracrine communication loop. Our findings reveal a novel mechanism for diversity and division of labor in innate immune cells.
A conductive hydrogel based on alginate and carbon nanotubes for probing microbial electroactivity
Laboratoire Colloïdes et Matériaux Divisés - Leopold Mottet, Domitille Le Cornec, a Jean-Marc Noe, Frederic Kanoufi, Brigitte Delord, Philippe Poulin, Jerome Bibettea and Nicolas Bremond
Soft Matter - 14 1434 - DOI: 10.1039/c7sm01929g - 2018
Some bacteria can act as catalysts to oxidize (or reduce) organic or inorganic matter with the potential
of generating electrical current. Despite their high value for sustainable energy, organic compound
production and bioremediation, a tool to probe the natural biodiversity and to select most efficient
microbes is still lacking. Compartmentalized cell culture is an ideal strategy for achieving such a goal but
the appropriate compartment allowing cell growth and electron exchange must be tailored. Here, we
develop a conductive composite hydrogel made of a double network of alginate and carbon nanotubes.
Homogeneous mixing of carbon nanotubes within the polyelectrolyte is obtained by a surfactant
assisted dispersion followed by a desorption step for triggering electrical conductivity. Dripping the
mixture in a gelling bath through simple extrusion or a double one allows the formation of either plain
hydrogel beads or liquid core hydrogel capsules. The process is shown to be compatible with the
bacterial culture (Geobacter sulfurreducens). Bacteria can indeed colonize the outer wall of plain beads
or the inner wall of the conductive capsules’ shell that function as an anode from which electrons
produced by the cells are collected.

515 publications.