%0 Book Section %1 statphys23_1061 %A Lagleize, J.M. %A Poirier, C. %A Lamblet, M. %A Delord, B. %A Bassereau, P. %A Johannes, L. %A Effenterre, D. Van %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K adhesion biomembrane biomimetic cell colloids force membrane probe receptors statphys23 system topic-10 %T Interaction between colloidal particles and cells: global and local statistical approach %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=1061 %X Viruses infecting a cell or drug delivering particles targeting a specific tissue are both situations where a suspension of colloidal objects is in contact with a cell membrane. Quantifying and understanding the adhesion thermodynamics and kinetics of this situation is a challenge where the coupling between physics and biology is important. Indeed, these particles - bearing specific ligands at their surface which might bind to receptors present in the membrane - are sufficiently small to be brownian and thus described by usual thermodynamics as for freely diffusing proteins, but they are large on the scale of the receptors and thus interact with the membrane more like a surface would do (with multiple binding, receptor recruitment, steric effect …as described in surface/cell adhesion). This may lead to unexpected behaviors. Experimentally, we study the interaction between particles and epithelial cells. Through their functionalization with either a peptide or a protein, we are able to target different receptors specifically. In order to understand the physico-chemical parameters involved in the adhesion, we use a global approach based on statistic measurement of the amount of bound colloids and a local approach based on the direct measurement of the force involved, owing to a micropipette set-up (Biomembrane Force Probe). Using flow cytometry and confocal microscopy, we are able to characterize both the kinetics and the thermodynamics of the interaction and have been able to put forward the role of the diffusion of receptors. Moreover we reproduce the behavior obtained with living cells by using a minimal biomimetic system on giant vesicles, which allows us to go deeper in the understanding. Theoretical aspects of the interaction between colloidal particles and cells will also be discussed. Using a simple thermodynamical approach, we have proposed that the time spent by each colloid on the cell surface could drastically depend on the bulk colloid concentration, due to a competition between colloids for mobile receptors. This effect might have consequences on the possible internalization of viruses or drug carriers.

@incollection{statphys23_1061, abstract = {Viruses infecting a cell or drug delivering particles targeting a specific tissue are both situations where a suspension of colloidal objects is in contact with a cell membrane. Quantifying and understanding the adhesion thermodynamics and kinetics of this situation is a challenge where the coupling between physics and biology is important. Indeed, these particles - bearing specific ligands at their surface which might bind to receptors present in the membrane - are sufficiently small to be brownian and thus described by usual thermodynamics as for freely diffusing proteins, but they are large on the scale of the receptors and thus interact with the membrane more like a surface would do (with multiple binding, receptor recruitment, steric effect …as described in surface/cell adhesion). This may lead to unexpected behaviors. Experimentally, we study the interaction between particles and epithelial cells. Through their functionalization with either a peptide or a protein, we are able to target different receptors specifically. In order to understand the physico-chemical parameters involved in the adhesion, we use a global approach based on statistic measurement of the amount of bound colloids and a local approach based on the direct measurement of the force involved, owing to a micropipette set-up (Biomembrane Force Probe). Using flow cytometry and confocal microscopy, we are able to characterize both the kinetics and the thermodynamics of the interaction and have been able to put forward the role of the diffusion of receptors. Moreover we reproduce the behavior obtained with living cells by using a minimal biomimetic system on giant vesicles, which allows us to go deeper in the understanding. Theoretical aspects of the interaction between colloidal particles and cells will also be discussed. Using a simple thermodynamical approach, we have proposed that the time spent by each colloid on the cell surface could drastically depend on the bulk colloid concentration, due to a competition between colloids for mobile receptors. This effect might have consequences on the possible internalization of viruses or drug carriers.}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Lagleize, J.M. and Poirier, C. and Lamblet, M. and Delord, B. and Bassereau, P. and Johannes, L. and Effenterre, D. Van}, biburl = {https://www.bibsonomy.org/bibtex/2eb684db910565466f9fabee5b52d5ad5/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {9d2c52118401d6e984018b476ea02226}, intrahash = {eb684db910565466f9fabee5b52d5ad5}, keywords = {adhesion biomembrane biomimetic cell colloids force membrane probe receptors statphys23 system topic-10}, month = {9-13 July}, timestamp = {2007-06-20T10:16:38.000+0200}, title = {Interaction between colloidal particles and cells: global and local statistical approach}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=1061}, year = 2007 }