Protein patterning in polycarbonate microfluidic channels

Abstract

In this work protein patterning has been demonstrated within a polycarbonate microfluidic device. Channel structures were first coated by plasma polymerization of allylamine (ALAPP) followed by 'cloud point' grafting of polyethylene oxide (PEO), resulting in a protein repellent surface. Excimer laser micromachining was used to pattern the PEO to control protein localisation. Subsequent removal of a sacrificial layer of polycarbonate resulted in the patterned polymer coating only within the channels of a simple fluidic device. Following a final diffusion bonding fabrication step the devices were filled with a buffer containing streptavidin conjugated with fluorescein, and visualized under a confocal fluorescence microscope. This confirmed that protein adhesion occurred only in laser-patterned areas. The ability to control protein adhesion in microfluidic channels leads to the possibility of generating arrays of proteins or cells within polymer microfluidics for cheap automated biosensors and synthesis systems.