Université PSL



Laboratoire :
Auteur :
Revue :
Année :
Red blood celles decorated with functionalized core-shell magnetic nanoparticles : elucidation of the adsorption mechanism
T. D. Mai, F. D’Orlyé, C. Menager, A. Varenne, M. Siaugue
Chem. Comm. - 49(47) :5393-5 - DOI:10.1039/c3cc41513a. - 2013
The decoration of red blood cells (RBCs) with aminated and carboxylated core-shell magnetic nanoparticles (CSMNs) was studied and elucidated. It was demonstrated that only aminated CSMNs could decorate the RBCs and their adsorption interaction is mainly ruled by electrostatic attraction between the positively charged amino groups on CSMNs and the abundant sialic acid groups on the outer surface of RBCs.
Surface functionalization of COC microfluidic materials by plasma and click chemistry processes
Y. Ladner, F. D’orlye, C. Perrard, B. Da Silva, C. Guyon, M. Tatoulian, S. Griveau, F. Bedioui & A. Varenne
Plasma Process - 10(11) :959-69 - DOI:10.1002/ppap.201300066 - 2013
A robust method for COC surfaces functionalization was developed for the first time by plasma polymerization. 1-bromopropane in the vapor phase allowed the formation of a brominated deposit on COC surfaces, which stability, homogeneity and chemical nature were evaluated for different experimental conditions. The analysis of vapor phase was achieved by mass spectrometry to control brominated precursor fragmentation. Following nucleophilic exchange in the presence of NaN3 to convert the brominated surface to azide-bearing surface, these modified COC were further functionalized with a fluorescent alkyne, via the copper-catalyzed azide–alkyne cycloaddition reaction, i.e. “click” reaction. Surface modifications were characterized by water contact angle measurement, ellipsometry, electrochemical microscopy, XPS, IR and fluorescence microscopy. This new process was proved to be efficient and stable in time up to 7 days.
Horseradish peroxidase nanopatterned electrodes by click chemistry: Application to the electrochemical detection of paracetamol
D. Quinton, A. Maringa, S. Griveau, T. Nyokong & F. Bedioui
Electrochemistry Communications - 31 :112-5 - https://doi.org/10.1002/elan.201300030 - 2013
Electrochemical DNA-biosensors : two-electrode set up well adapted for miniaturized devices
M. Lazerges, V. T. Tal, P. Bigey, D. Scherman & F. Bedioui
Sensors & Actuators - B 182 :510-513 - DOI:10.1016/j.snb.2013.02.098 - 2013
The proof of concept of a DNA-biosensor based on a two-electrode electrochemical setup and using a microelectrode as working electrode, well adapted for detection in microliter samples and miniaturization, is presented herein. A 23-base DNA-probe self-assembled monolayer was first formed onto a 50 μm-diameter gold surface. The microelectrode extremity was then immersed in a 50 μL DNA-target solution drop itself deposited onto a 2 mm-diameter gold counter electrode. Transduction occurs via long-range electron transfer, which is enhanced subsequently to hybridization, due to DNA-base π-stacking. Single mismatch detection of this first prototype was matched at room temperature in the nanomolar range without any optimization.
High-resolution dose-response screening using droplet-based microfluidics
O.J. Miller, A.E. Harrak, T. Mangeat, J.-C. Baret, L. Frenz, B. El Debs, E. Mayot, M.L. Samuels, E.K. Rooney, P. Dieu, M. Galvan, D.R. Link and A.D. Griffiths
Proc. Nat. Acad. Sci. USA - 109(2) :378–83 - DOI:10.1073/pnas.1113324109 - 2012
A critical early step in drug discovery is the screening of a chemical library. Typically, promising compounds are identified in a primary screen and then more fully characterized in a dose–response analysis with 7–10 data points per compound. Here, we describe a robust microfluidic approach that increases the number of data points to approximately 10,000 per compound. The system exploits Taylor–Aris dispersion to create concentration gradients, which are then segmented into picoliter microreactors by droplet-based microfluidics. The large number of data points results in IC50 values that are highly precise (± 2.40% at 95% confidence) and highly reproducible (CV = 2.45%, n = 16). In addition, the high resolution of the data reveals complex dose–response relationships unambiguously. We used this system to screen a chemical library of 704 compounds against protein tyrosine phosphatase 1B, a diabetes, obesity, and cancer target. We identified a number of novel inhibitors, the most potent being sodium cefsulodine, which has an IC50 of 27 ± 0.83 μM.
A completely in vitro ultrahigh-throughput droplet-based microfluidic screening system for protein engineering and directed evolution
Fallah-Araghi, J.-C. Baret, M. Ryckelynck, and A.D. Griffiths
Lab. Chip - 12(5) :882–91 - DOI: 10.1039/c2lc21035e - 2012
In vitro screening systems based on the coupled transcription and translation of genes using cell-free systems have a number of attractive features for protein engineering and directed evolution. We present a completely in vitro ultrahigh-throughput screening platform using droplet-based microfluidics. Single genes are compartmentalized in aqueous droplets, dispersed in inert carrier oil, and amplified using the polymerase chain reaction (PCR). After amplification, the droplets, now containing 30,000 copies of each gene, are fused one-to-one with droplets containing a cell-free coupled transcription-translation (IVTT) system and the reagents for a fluorogenic assay. Fluorescence-activated electrocoalescence with an aqueous stream is then used to selectively recover genes from droplets containing the desired activity. We demonstrate, by selecting mixtures of lacZ genes encoding the enzyme β-galactosidase and lacZmut genes encoding an inactive variant, that this system can sort at 2000 droplets s(-1): lacZ genes were enriched 502-fold from a 1 : 100 molar ratio of lacZ : lacZmut genes. Indeed, the false positive and false negative error rates were both <0.004 and the results indicate that enrichment is not limited by the sorting efficiency, but by the co-encapsulation of multiple genes in droplets, which is described by the Poisson distribution. Compared to screening using microtiter plate-based systems, the volume and cost of PCR and IVTT reagents are reduced by almost 10(5)-fold, allowing the screening of 10(6) genes using only 150 μL of reagents.
Functional single-cell hybridoma screening using droplet-based microfluidics
B. El Debs, R. Utharala, I.V. Balyasnikova, A.D. Griffiths and C.A. Merten
Proc. Nat. Acad. Sci. USA - 109(29) :11570-5 - DOI: 10.1073/pnas.1204514109 - 2012
Monoclonal antibodies can specifically bind or even inhibit drug targets and have hence become the fastest growing class of human therapeutics. Although they can be screened for binding affinities at very high throughput using systems such as phage display, screening for functional properties (e.g., the inhibition of a drug target) is much more challenging. Typically these screens require the generation of immortalized hybridoma cells, as well as clonal expansion in microtiter plates over several weeks, and the number of clones that can be assayed is typically no more than a few thousand. We present here a microfluidic platform allowing the functional screening of up to 300,000 individual hybridoma cell clones within less than a day. This approach should also be applicable to nonimmortalized primary B-cells, as no cell proliferation is required: Individual cells are encapsulated into aqueous microdroplets and assayed directly for the release of antibodies inhibiting a drug target based on fluorescence. We used this system to perform a model screen for antibodies that inhibit angiotensin converting enzyme 1, a target for hypertension and congestive heart failure drugs. When cells expressing these antibodies were spiked into an unrelated hybridoma cell population in a ratio of 1:10,000 we observed a 9,400-fold enrichment after fluorescence activated droplet sorting. A wide variance in antibody expression levels at the single-cell level within a single hybridoma line was observed and high expressors could be successfully sorted and recultivated.
Fine control of nuclear confinement identifies a threshold deformation leading to lamina rupture and induction of specific genes
Berre M, Aubertin J, Piel M
Integr Biol (Camb) - 4(11) :1406-14 - DOI:10.1039/c2ib20056b - 2012
The quest to understand how the mechanical and geometrical environment of cells impacts their behavior and fate has been a major force driving the recent development of new technologies in cell biology research. Despite rapid advances in this field, many challenges remain in order to bridge the gap between the classical and simple cell culture plate and the biological reality of actual tissue. In tissues, cells have their physical space constrained by neighboring cells and the extracellular matrix. Here, we propose a simple and versatile device to precisely and dynamically control this confinement parameter in cultured cells. We show that there is a precise threshold deformation above which the nuclear lamina breaks and reconstructs, whereas nuclear volume changes. We also show that different nuclear deformations correlate with the expression of specific sets of genes, including nuclear factors and classical mechanotransduction pathways. This versatile device thus enables the precise control of cell and nuclear deformation by confinement and the correlative study of the associated molecular events.
The first World Cell Race
Maiuri P, Terriac E, Paul-Gilloteaux P, Vignaud T, McNally K, Onuffer J, Thorn K, Nguyen PA, Georgoulia N, Soong D, Jayo A, Beil N, Beneke J, Hong Lim JC, Pei-Ying Sim C, Chu YS; WCR participants, Jiménez-Dalmaroni A, Joanny JF, Thiery JP, Erfle H, Parson
Curr Biol. - 22(17) :R673-5 - DOI:10.1016/j.cub.2012.07.052 - 2012
Motility is a common property of animal cells. Cell motility is required for embryogenesis [1], tissue morphogenesis [2] and the immune response [3] but is also involved in disease processes, such as metastasis of cancer cells [4]. Analysis of cell migration in native tissue in vivo has yet to be fully explored, but motility can be relatively easily studied in vitro in isolated cells. Recent evidence suggests that cells plated in vitro on thin lines of adhesive proteins printed onto culture dishes can recapitulate many features of in vivo migration on collagen fibers [5,6]. However, even with controlled in vitro measurements, the characteristics of motility are diverse and are dependent on the cell type, origin and external cues. One objective of the first World Cell Race was to perform a large-scale comparison of motility across many different adherent cell types under standardized conditions. To achieve a diverse selection, we enlisted the help of many international laboratories, who submitted cells for analysis. The large-scale analysis, made feasible by this competition-oriented collaboration, demonstrated that higher cell speed correlates with the persistence of movement in the same direction irrespective of cell origin.
Predicting division plane position and orientation
Minc N, Piel M.
Trends Cell Biol. - 22(4) :193-200 - DOI:10.1016/j.tcb.2012.01.003 - 2012
Predicting cellular behavior is a major challenge in cell and developmental biology. Since the late nineteenth century, empirical rules have been formulated to predict the position and orientation of mitotic cleavage planes in plant and animal cells. Here, we review the history of division plane orientation rules and discuss recent experimental and theoretical studies that refine these rules and provide mechanistic insights into how division can be predicted. We describe why some of these rules may better apply to certain cell types and developmental contexts and discuss how they could be integrated in the future to allow the prediction of division positioning in tissues.

405 publications.