Nanoplasmonic sensing combined with artificial cell membranes
This chapter is dedicated to nanoplasmonic sensing systems made compatible with studies of artificial cell membranes. After a short motivation to the opportunity of sensors designed for such studies to fill an existing technological gap, we introduce basic features of cell membranes and common mimics of the cell membrane that have been proven useful in various bioanalytical sensing applications. With suitable examples from the literature, subsequent sections exemplify how nanoplasmonics can be used to study different reactions that are associated with cell membranes. In particular, focus is on unique possibilities provided by different types of nanoplasmonic structures. For example, while discrete nanoplasmonic particles can be used as mobile probes attached to cell membranes, conductive nanoplasmonic hole structures can be used for combined optical and electrical transduction. Examples on how the latter possibility has enabled cell membrane-related reactions to be investigated with nanoplasmonic sensing combined with quartz crystal microbalance with dissipation monitoring are presented. Another key aspect of nanoplasmonic structures is that the plasmonic field (and hence the refractive index sensitivity) is strongest at the sensor surface and decays rapidly away from the surface. We describe how this feature provides a means to monitor structural changes of molecules on the surface, such as the spontaneous rupture of lipid vesicles into a supported lipid bilayer on silicon oxide-coated nanoplasmonic holes.