Controlled photopolymerization of hydrogel microstructures inside microchannels for bioassays.

This paper describes a photolithography approach to generate hydrogel microstructures inside microchannels on the basis of controlled photopolymerization of poly(ethylene glycol) diacrylate precursor by using a fluorescence microscope. The controlled photopolymerization offers: (1) morphology control on hydrogel microstructures with different illumination conditions; (2) position control on hydrogel microstructures to make it possible for the generation of arrayed hydrogel microstructures and encapsulation of single cells; (3) a convenient approach for immobilization of a variety of materials onto the solid substrates for bioassays. For demonstration, we performed a microfluidic assay for DNA oligomer detection on the arrayed hydrogel microstructures.