The development of Lab-on-a-Chip devices with integrated bio-analysis functions requires a complex network of microfluidic transport and processes. Many of these functions call for the isolation or separation of specific bio-particles or cells. The design of a miniaturized cell-sorting device for handheld operation must follow the strict parameters associated with Lab-on-a-Chip technology. The limitations include applied voltage, high efficiency of cell-separation, repeatability, size, flow control, and cost, among others. Currently used designs have achieved successful levels of cell-isolation. However, further improvements in the microfluidic chip design are important for incorporation into larger systems. This study evaluates specific design modifications that contribute to the reduction of required applied potential aiming for developing portable devices, improved operation reliability by minimizing induced pressure disturbance when electrokinetic pumping is employed and incorporating online filters to reduce channel blockage, and improved flow control by incorporating directing streams achieving dynamic sorting and counting. The chip designs fabricated in glass and polymeric materials include asymmetric channel widths for sample focusing, nonuniform channel depth for minimizing induced pressure disturbance, directing streams to assist particle flow control, and online filters for reducing channel blockage. Fluorescence-based visualization of electrokinetic focusing, flow field phenomena, and dynamic cell-sorting demonstrate the advantages of the chip design. Numerical simulations in COMSOL are validated by the experimental data and used to investigate the effects of channel geometry and fluid properties on the flow field.
How to Implement ISO 9000s as Supplier of Flow Control Equipment.
