Vesicle adhesion visualized with total internal reflection imaging ellipsometry biosensor

The behavior of giant lipid vesicles (GUVs) interacting with an adhesive surface coated with poly-l-lysine is investigated by a biosensor based on total internal reflection imaging ellipsometry (TIRIE). The adhesion of GUVs on the adhesive surface is regulated by the concentration of the poly-l-lysine coating, the pH of the vesicle suspension, and the flow rate of the suspending fluid. The TIRIE biosensor detects very clearly and sensitively GUV adsorption, flattening, rupture, and de-adhesion, all these behaviors being independently observed by phase contrast microscopy. These results show that the setting of the TIRIE biosensor, optimized for molecular sensing can be extended to GUV sensing. This work paves the way to develop a new sensitive high-throughput, low-consumption and low-cost biosensor technology for micron-size objects such as cells, capsules and liposomes.