Development of a Diffusion Limited Microfluidic Module for DNA Purification via Phenol Extraction

Abstract

Purification of Deoxyribonucleic acid (DNA) by organic-aqueous liquid extraction, also called phenol extraction, is a standard technique commonly utilized in biology laboratories. In order to minimize interaction energies, membrane components and proteins naturally partition to the organic (phenol) phase while the DNA stays in the aqueous phase, where it can be easily removed. In recent years, microfluidics has become a driving force toward more efficient and autonomous platforms for fluid based diagnostics, chemical reaction chambers, separation and preparation of biological materials. In this work, fabrication, and performance of a long microfluidic device for DNA extraction are presented. The devices were fabricated using soft lithography to transfer lithographically defined features into a PDMS structure via replica molding. Stratified-flow experiments using a rhodamine dye conjugated bovine serum albumin protein (BSA) in an aqueous phase were conducted to demonstrate the ability to remove proteins from the aqueous phase into the phenol phase. Additionally, the study of BSA partitioning and DNA isolation in a two-phase system under stratified flow condition were presented, separately and conjunctly. Finally, protein partitioning and DNA recovery obtained with this device could be compared with other types of mixing and extraction such as mixing by droplet formation and electrohydrodynamic (EHD) instability.