Abstract

All-in-one Droplet Microfluidic Chips for Biomolecular Assays

Tza-Huei Wang, Associate Professor, Johns Hopkins University

The greatest challenge in implementing complex bioanalytical assays on a chip-sized platform is to develop a fluid control system that is simple yet fully functional. Manipulation of droplets on an open surface promises easier, more flexible, and more functionally integrated liquid control, than does continuous flow microfluidics. The talk focuses on the development of a droplet microfluidic platform for the detection of disease biomarkers and infectious pathogens using crude biosamples. The platform exploited the dual functionality of silica superparamagnetic particles (SSP) for solid phase extraction of DNA and magnetic actuation. This enabled the integration of sample preparation and genetic analysis within discrete droplets, including the steps of cell lysis, DNA binding, washing, elution, amplification and detection. The microfluidic device was self contained, with all reagents stored in droplets, thereby eliminating the need for fluidic coupling to external reagent reservoirs. In addition, a compact sample handling stage, which integrated the magnet manipulator, the droplet microfluidic device and a Peltier thermal cycler, was built for convenient droplet manipulation and real-time detection. Feasibility of the platform was demonstrated by analysing ovarian cancer biomarker Rsf-1 and detecting infectious pathogen with the real time polymerase chain reaction.