Segregation of micrometer-dimension biosensor elements on a variety of substrate surfaces

With the rapid development of micro total analysis systems and sensitive bi osensing technologies, it is often desirable to immobilize biomolecules to small areas of surfaces other than silicon. To this end, photolithographic techniques were used to derivatize micrometer-sized, spatially segregated b iosensing elements on several different substrate surfaces. Both an interfe rence pattern and a dynamic confocal patterning apparatus were used to cont rol the dimensions and positions of immobilized regions. In both of these m ethods, a UV laser was used to initiate attachment of a photoactive biotin molecule to the substrate surfaces. Once biotin was attached to a substrate , biotin/avidin/biotin chemistry was used to attach fluorescently labeled o r nonlabeled avidin and biotinylated sensing elements such as biotinylated antibodies. Dimensions of 2-10 mu m were achievable with these methods. A w ide variety of materials, including glassy carbon, quartz, acrylic, polysty rene, acetonitrile-butadiene-styrene, polycarbonate, and poly(dimethylsilox ane), were used as substrates. Nitrene- and carbene-generating photolinkers were investigated to achieve the most homogeneous films. These techniques were applied to create a prototype microfluidic sensor device that was used to separate fluorscently labeled secondary antibodies.