NANOSTRUCTURE OF SUPPORTED PHOSPHOLIPID MONOLAYERS AND BILAYERS BY SCANNING PROBE MICROSCOPY

Near-field scanning optical and atomic force microscopy were used to i mage structural details of supported lipid monolayers and bilayers. Co mpressed DPPC monolayers exhibited dense web-like structures whereas D PPE monolayers were more uniform with elongated inclusion domains of f luorescent probes, When a second lipid monolayer was self-assembled on a supported monolayer [Kalb et al., Biochim. Biophys. Acta 1103 (1992 ) 307], the structure of the resulting supported bilayer strongly depe nded on the coupling monolayer. On coupling monolayers of DPPC, the bi layers exhibited domains with finger-like extensions. Much more unifor m bilayers were obtained when the coupling layer was DPPE. Towards the goal of developing a biosensor for the detection of viruses in biolog ical fluids, bilayers were constructed with 10 mol% of the ganglioside G(Dia) in the outer monolayer. Specific binding of influenza viruses to G,,, receptors was monitored by total internal reflection fluoresce nce and atomic force microscopy.