The separation of target nucleic acid and protein sequences from biological samples has emerged as a significant process in today’s diagnostics and detection strategies. In addition to the possible clinical applications, the fundamental understanding of target and sequence specific hybridization and adsorption on surface modified magnetic beads is of high value. In this work we will first describe a novel microfluidic platform that utilizes a mobile magnetic field in static microfluidic channels, where single stranded DNA (ssDNA) molecules are isolated via nucleic acid hybridization. Our results establish efficient isolation of biotinylated capture probe (BP) using streptavidin-coated magnetic beads. We investigate the hybridization of target ssDNA with BP bound to beads and explain these hybridization kinetics using a dual-species kinetic model. The number of hybridized target ssDNA molecules are determined to be about 6.5 times less than that of BP on the bead surface, due to steric hindrance effects. The hybridization of target ssDNA with non-complementary BP bound to bead are also examined, and non-specific hybridization are found to be insignificant. Finally, we will demonstrate highly efficient capture and isolation of target ssDNA in the presence of non-target ssDNA, where as low as 1% target ssDNA can be detected from mixture. We will repeat above analysis for our experiments to isolate target protein molecules.
The microfluidic method described in this work is significantly relevant and is broadly applicable, especially towards point-of-care biological diagnostic platforms that require binding and separation of known target biomolecules, such as RNA, ssDNA, or protein.
See more of this Group/Topical: Engineering Sciences and Fundamentals