(199c) Photoswitchable Quantum Dots Probes for Superresolution Microscopy
AIChE Annual Meeting
Monday, October 30, 2017 - 3:15pm to 4:45pm
QD probes were designed using the principles of Förster resonance energy transfer (FRET) by radiative transfer of the QD (donor) fluorescence to a light sensitive material (acceptor) to achieve a dark state. Previous studies have shown that gold nanoparticles (AuNPs) are excellent acceptors, especially for QDs. Additionally, FRET is strongly dependent on the distance between the donor and acceptor. Therefore, the probe consisted of QD-AuNP pairs formed using a DNA linker, whose length can be precisely controlled by the number of base pairs. The QD-AuNP pairs were therefore synthesized by conjugating the nanoparticle surfaces with complementary single stranded-deoxyribonucleic acid (ss-DNA). Reversible photoswitching was induced in these probes by utilizing photo-sensitive azobenzene modified DNA strands that can induce reversible DNA hybridization through cis-trans conversions induced by light. In this research, QD coatings were optimized to reduce the QD-AuNP separation distance and QD-AuNP spectral overlap were optimized. Both are crucial for efficient FRET. These probes are being analyzed using fluorescence spectroscopy by simultaneously modulating the photo-sensitive-DNA with a laser source to measure quenching efficiency. The optimized probes developed from this study will then be tested by comparative STORM imaging.