A Microfluidic Approach to Selection and Enrichment of Aptamers for Biomolecules and Cells

This thesis presents microfluidic devices for selection and amplification of nucleic acids (aptamers) that bind to specific targets. Aptamers are very attractive molecules in many biological applications due to their interesting properties including high target binding affinities and stability. Using conventional platforms for aptamer generation (SELEX, systematic evolution of ligands by exponential enrichment) is labor-intensive and time consuming. Microfluidic devices have been developed to improve the aptamer enrichment efficiency. However, aptamer generation using these devices is still inefficient because they require complicated flow control components for sample and reagent handling and additional off-chip processes. We developed microfluidic SELEX platforms for rapid isolation of aptamers that possess greatly simplified designs which enable easy chip fabrication and operation. The simplicity of the devices is achieved by utilizing a combination of bead-based selection and amplification of target binding nucleic acids, and gel-based electrokinetic transfer of nucleic acids. In the devices, nucleic acids that bind to targets are isolated on target-functionalized microbeads or