Distance-Dependent Fluorescence Resonance Energy Transfer Enhancement on Nanoporous Gold.

Fluorescence resonance energy transfers (FRET) between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) on nanoporous gold (NPG) are systematically investigated by controlling the distance between NPG and fluorescent proteins with polyelectrolyte multilayers. The FRET between CFP and YFP is significantly enhanced by NPG, and the maximum enhancement is related to both ligament size of NPG and the distance between NPG and proteins. With the optimized distance, 18-fold FRET enhancement was obtained on NPG compared to that on glass, and the conversion efficiency is about 90%. The potential to tune the characteristic energy transfer distance has implications for applications in nanophotonic devices and provides a possible way to design sensors and light energy converters.