Rapid Directed Evolution of Molecules In Microfluidic Systems

Current techniques in high performance bioseparations are limited by the inherent coupling among three competing parameters: throughput, purity, and recovery of rare species.  Our work utilizes unique advantages of microfluidics technology to decouple these competing parameters by precise and reproducible generation of separation forces that are not accessible in conventional, macroscopic systems.  In this work, we will first discuss novel methods of generating ultrahigh magnetic field gradients in microchannels for high purity molecular separations. Then we describe our recent work in utilizing this technique for directed evolution of molecules, such that affinity reagents based on nucleic acids (aptamers) and proteins (monobodies) can be generated with unprecedented efficiencies. We provide the theoretical framework behind the selection efficiencies, and present our recent results in using deep sequencing to identify optimal molecules using bioinformatics. Finally, we present innovative methods of evolving molecules that are capable of performing complex functions including binding-induced structure switching.