A PDMS Sample Pretreatment Device for the Optimization of Electrokinetic Manipulations of Blood Serum

• Main Author: Abram, Timothy J
• Format: Others
• Published: DigitalCommons@CalPoly 2009
• Subjects: Pretreatment; Microfluidic; Micro-mixing; Diagnostic; Electrokinetic; PDMS; Biomedical Engineering and Bioengineering
• Online Access: https://digitalcommons.calpoly.edu/theses/172; https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1182&context=theses

This project encompasses the design of a pretreatment protocol for blood serum and adaption of that protocol to a microfluidic environment in order to optimize key sample characteristics, namely pH, conductivity, and viscosity, to enable on-chip electrokinetic separations. The two major parts of this project include (1) designing a pretreatment protocol to optimize key parameters of the sample solution within a target range and (2) designing /fabricating a microchip that will effectively combine the sample solution with the appropriate buffers to replicate the same bench-scale protocol on the micro-scale. Biomarker detection in complex samples such as blood necessitates appropriate sample “pretreatment” in order for specific markers to be isolated through subsequent separations. This project, though using conventional mixing techniques and buffer solutions, is one of the first to observe the effects of the combination of micro-mixing and sample pretreatment in order to create an all-in-one “pretreatment chip”. Using previous literature related to capillary electrophoresis, a bench-scale pretreatment protocol was developed to tune these parameters to an optimal range. A PDMS device was fabricated and used to combine raw sample with specific buffer solutions. Off-chip electrodes were used to induce electrokinetic micro-mixing in the mixing chamber, where homogeneous analyte mixing was achieved in less than one second using an 800V DC pulse wave. Ultimately, we wish to incorporate this device with pre-fabricated electrokinetic devices to optimize certain bioseparations.