Electrokinetic injection is commonly utilized in capillary chip electrophoresis (CE) even though mobility and matrix bias makes quantitation difficult. Hence, injection techniques that provide for both reproducible and precise injection of sample are warranted. Herein, we describe a new approach to sample introduction in poly(dimethylsiloxane) (PDMS) microfluidic devices fabricated by multilayer soft lithography (MSL) techniques utilizing a combination of both hydrostatic and hydrodynamic pressure instead of electrokinetic forces. The applicability of both the pressure injection technique and the recently introduced magnetic valve were studied and optimized using common food dyes. Using a homemade CE instrument coupled to an inverted microscope mixtures of dyes were injected and visualized at varying points in the chip and color images analyzed using a homemade graphing program.
Journal: TechConnect Briefs
Volume: 3, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 3
Published: May 20, 2007
Pages: 383 - 384
Industry sector: Sensors, MEMS, Electronics
Topics: Micro & Bio Fluidics, Lab-on-Chip