Micro-fluidic channels on nanopatterned substrates: Monitoring protein binding to lipid bilayers with surface-enhanced Raman spectroscopy

Coherent arrays of nano-holes in anodized aluminum oxide (AAO) were employed to enhance Raman signals of test molecules. Signal enhancement was obtained under optimal light coupling conditions and was attributed to formation of standing surface plasmon (SP) waves - the SP modes were scattered back-and-forth along the periodically perforated substrate surface. The aluminum oxide pores also allowed for lining the lower surface of micro-fluidic channels with biotinylated lipid bilayers which in turn, were used for binding of streptavidin to the nanopores area. Thus, we demonstrated targeted experiments through monitoring binding events of analytes (streptavidin) to lipid bilayer membranes (the analytes' target).