Biomedical subjects
Publications and source records attributed to Jean-Marc di Meglio.
We present a method to control the osmotic stress of giant unilamellar vesicles (GUV) and we report an original shrinkage mode of the vesicles: the volume reduction is accompanied by the formation of inverted daughter vesicles which gives the shrunk vesicles the appearance of raspberries. We analyze this peculiar shrinkage and we propose some physical origins for the observed phenomena.
The molecular details of adhesion mechanics in phospholipid bilayers have been studied using atomic force microscopy (AFM). Under tension fused bilayers of dipalmitoylphosphatidylcholine (DPPC) yield to give non-distance dependent and discrete force plateaux of 45.4, 81.6 and 113+/-3.5 pN. This behaviour may persist over distances as great as 400 nm and suggests the stable formation of a cylindrical tube which bridges the bilayers on the two surfaces. The stability of this connective structure may have implications for the formation of pili and hence for the initial stage of bacterial conjugation. Dimyristoylphosphatidylcholine (DMPC) bilayers also exhibit force plateaux but with a much less pronounced quantization. Bilayers composed of egg PC, sterylamine and cholesterol stressed in a similar way show complex behaviour which can in part be explained using the models demonstrated in the pure lipids.