Turning light-guiding nanowires into a fluorescence-based biosensing assay*

In some designs, semiconductor nanowires act as nanoscale optical fibres. Their quasi-1D structure can allow for the coupling of photons, which are then guided along the central axis of the nanowire structure to be emitted through its tip. In this talk, I will discuss our collaborative effort to passivate the surface of nanowires with cleavage-activated fluorogenic peptides, thereby turning a lattice of GaP nanowires into a high-throughput biosensing assay. I will present our results showing that we are able to detect the presence and activity of enzymes free in solution. This detection happens via the increase in light intensity at the nanowire tips as the surface-tethered substrates are cleaved and become fluorescent. The generality of this finding is further improved with use of our newly developed triblock-copolymer surface chemistry, which enables both specific modification of nanowire surfaces and the blocking of undesired nonspecific adhesion (e.g. of quantum dots from solution).