(16b) Single Molecule Studies of Ionic Strength Effects on Interfacial DNA Searching and Hybridization
In this work, we utilize single-molecule total internal fluorescence microscopy to characterize the effect of electrostatic screening on oligonucleotide transport and hybridization at a solid-liquid interface by introducing dissolved DNA to these surfaces at various ionic strengths and a range of surface grafting density of immobilized probes. Through molecular tracking, we are able to characterize heterogeneous searching behaviors of molecules via anomalous surface diffusion. We correlate changes in molecular transport with changes in association kinetics between DNA strands, allowing us to assess how transport limitations affect successful hybridization. This provides insight into the specific mechanisms of surface hybridization that are affected by electrostatic repulsion.