Resist-free patterning of surface architectures in polymer-based microanalytical devices.

The ability to form patterns of chemically reactive surface functionalities in microanalytical devices using a simple photopatterning approach without the need for photoresist-based methods is described. Direct UV exposure of the surfaces of poly(methyl methacrylate), PMMA, and poly(carbonate), PC, microfluidic devices through optical masks leads to the production of patterns of near monolayer quantities of surface carboxylic acid groups as determined by surface coverage, X-ray photoelectron spectroscopy, and fluorescence microscopy experiments. Formation of the reactive carboxylic acid groups without significant physical (topographical) damage to the polymer device substrates is achieved by use of low UV fluence and exposure times. Modification of the patterned, surface carboxylic acid groups with metals, thermally responsive polymers, and antibodies results in microfluidic devices possessing metallic interconnects and detection electrodes and the ability to capture intact biological cells and proteins from solution.