Voltage-controlled programmable patterning of proteins and cells in a microfluidic device

The ability to organize proteins and cells into well-defined micropatterns on a surface is essential for high throughput biochip-based analysis of biomolecules interactions and thus is a critical technology for the advancement of proteomics and cancer research, cell studies, tissue engineering, and drug screening. A microfluidic system that has the versatility to rapidly program the placement of proteins and cells into patterns in microchannels would be invaluable for the development of configurable devices that give users flexibility to decide and change the placement of biomolecules on a surface. Several protein and cell patterning methods have been presented previously, but these methods are not directly applicable for the development of highly flexible, versatile protein/cell patterning microfluidic devices because they lack the ability to programmably organize proteins or cells into high-resolution patterns. This thesis work has developed a microfluidic device that is the first in demonstrating the capability to rapidly program the surface arrangement of proteins and cells into high-resolution, arbitrarily-shaped patterns as small as 3 mum in width. The presented patterning device is also the first that demonstrates con figurable protein densities on patterns by adjusting the applied voltage on electrodes, providing the possibility to tune signals for complex analytes and test conditions for a wide variety of biological assays. Controlled protein adsorption is achieved by switching the surface arrangement of a triblock copolymer monolayer on microelectrodes in the engineered microfluidic device via an electric potential, and cell micropatterns are generated from patterning cell-adhesive glycoproteins. The developed method can pattern proteins within 15 minutes and cells within 2 hours with post-device processing sample loading, which can significantly simplify the integration of biochip/microarray functions in microfluidic systems. Since the programmable biomolecule pattering is controlled by a voltage source, the developed method can provide a mean to realize a handheld system for immediate on-site applications, such as biomolecule identifications, clinical diagnostics, and epidemic disease surveillance. Furthermore, the cell patterning demonstrated in this research can be applied to cell culture technology and holds promise to achieve in-situ construction of cell composites within a microfluidic environment.