Adsorption Kinetics of Single-Stranded DNA on Functional Silica Surfaces and Its Influence Factors: An Evanescent-Wave Biosensor Study

Thorough understandings on the real-time kinetics involved in DNA adsorption on a solid surface is essential in various fields, such as in DNA hybridization studies, DNA extraction and purification, DNA-based biosensing, and gene-based medicine discovery. Herein, the real-time properties of single-stranded DNA (ssDNA) adsorption onto functional silica surfaces under various conditions were investigated using an evanescent wave optical biosensing platform. Results demonstrated that the driving force and adsorption mechanism of DNA were closely related to the kind of functional groups on the silica surfaces. The main driving forces of DNA adsorption onto hydroxyl- and protein-modified solid surfaces were the hydrophobic interaction, hydrogen bonding, and the interaction between DNA phosphate and functional groups on the silica surface, which strengthened with increased ionic strength. However, the electrostatic attraction between the negative charge of DNA and positive charge of the amino silica surface was...