Blood sample preparation using microfluidic platforms

This thesis focuses on integrating rare cell capture from blood on a disposable sample-preparation device for a portable platform. Such a module is the interface between a macroscopic world sample and any polymerase chain reaction (PCR)-based microfluidic system. Immunomagnetic separation of T cells from human blood and Jurkat cells from reconstituted horse blood was performed and characterized. Although more dilute cells are ultimately contemplated, the T cells or Jurkat cells considered in this study offered a good initial model of rare cells in blood.;A PCR procedure was optimized and adapted for the characterization of the capture efficiencies obtained on the tested devices. The method uses direct PCR amplification of a T cell receptor gamma gene junctional region. We described the use of paramagnetic beads for cell capture within microfluidic channels. After preliminary tests performed on a simple Y microfluidic device, eight different manifolds were designed and tested in an effort to reduce the analysis time, while maintaining the capture efficiency. A simple increase of the channel size for a quick processing of larger volumes of sample did not work for the immunomagnefc bead-bed method used in this study. It was necessary to split the flow into several smaller channels to get satisfactory capture efficiency.;We presented the first integration of micro-electrolysis pumps for the manipulation and initial processing of a blood sample. Jurkat cells were captured from a 7.5 muL reconstituted horse blood sample using a pair of electrolysis chambers, which were designed to work in a stepwise fashion. First the blood sample was delivered when the pre-labeled cells were captured, and then a buffer was used to wash the captured cells.;Preliminary results obtained for the fabrication of polycarbonate devices were described. A master fabricated in silicon was etched using DRIE and used to electroform a nickel relief as a secondary master with the reverse features of the Si surface. The Ni master was used to stamp features into PC substrates by hot embossing. The resulting substrates had the same pattern as the original Si master. Substrates were thermally bonded under optimized bonding parameters to a coverplate using a hydraulic press.