Extraction of plasma from whole blood using a deposited microbead plug (DMBP) in a capillary-driven microfluidic device

We presented a deposited microbead plug (DMBP)-based microfluidic device capable of extracting plasma from whole blood by capillary forces. This device was fabricated by reversibly bonding a PDMS slab with a straight channel to a hydrophilic glass substrate. The DMBP was easily constructed at the inlet of the channel within 2 min by a method of natural deposition of microbeads without the need of weirs or photopolymerization. Capillary forces generated mainly on the hydrophilic glass substrate provided a driving force during the fabrication of the DMBP and plasma extraction, resulting in simplicity of operations. The DMBP only allows blood plasma to pass through but blocks blood cells, which was demonstrated experimentally using sheep blood. The DMBP enabled to remain in its initial configuration during plasma extraction. The high quality plasma was obtained without contamination of microbeads and blood cells. This easy-to-use, easy-to-integrate, disposable the DMBP-based microfluidic device has the potential to be integrated with on-chip bioanalytical units for the applications of point-of-care diagnostics.