Single Molecule Fluorescence Imaging of DNA at Agarose Surfaces by Total Internal Reflection Fluorescence Microscopy

摘要

We performed single molecule fluorescence detection of YOYO-1 labeled A-DNA moleculesadsorbed on a solid substrate after treatment with different concentrations of agarose by total inter-nal reflection fluorescence microscopy (TIRFM). At agarose-modified surfaces, we found that molec-ular adsorption behaviors were dependent on agarose concentration, pH and ionic strength. Wefurther revealed the subtle differences among adsorptive forces. Both electrostatic interaction andhydrophobic interaction were the major driving force for adsorption of DNA molecules on agarosesurfaces. We also found that surface topography plays a role to a certain extent in the adsorptiondynamics. The characteristics of agarose surfaces were further assessed using contact angle (CA)measurements.