Integration of Optical Protein and Quantum Dot Films for Biosensing

The unique energy transfer interaction between the optical protein bacteriorhodopsin (bR) and CdSe/ZnS quantum dots (QDs) provides a potential modulation mechanism for bio- nano electronic application. We have utilized ionic-self assembled monolayer (I-SAM) techniques to create a novel alternating monolayer system of QDs and bR on a conductive ITO substrate. Results demonstrate the ability to efficiently create bR/QD multilayer films along with the ability to control bR/QD spacing on the nanometer scale. I-SAM films of this nature demonstrate a sharp decrease in QD emission when deposited in close proximity to bR, suggesting possible fluorescence resonance energy transfer (FRET) effects in a bR/QD nanoscale system. The ability to modulate the QD photonic output based on proximity to bR in the I-SAM films could provide a direct method to modulate the electrical output for bio-nano sensing applications.