Using surface plasmons to enhance the FRET efficiency of fluorescent molecules as a function of molecular spacing and relative orientation

This project explores using surface plasmon waves excited on nanopatterned gold surfaces to enhance the efficiency of Förster Resonance Energy Transfer (FRET) between donor and acceptor fluorescent molecules. Surface plasmons are known to enhance fluorescence efficiency by altering the local density of optical states. The periodicity of gold nanogratings allows for the excitation of multiple wavelengths of surface plasmons on a single substrate. Gold nanogratings were fabricated using a template stripping method. Following fabrication, the nanogratings are characterized. First, we measured the topology using an atomic force microscope to ensure proper transferring of the nanopattern. Then, we used white light spectroscopy to map out the wavelengths of surface plasmons as a function of the angle of incident light. Following characterization, DNA with attached donor and acceptor fluorescent molecules are then deposited on viable samples. The DNA ensures the precise distance and the relative orientation between the fluorescent molecules. In this talk, we will discuss optimizing the distance and orientation between the molecules for FRET enhancement.