Multifunctional Hydrogel Microparticles by Polymer-Assisted Photolithography.

Although standard lithography has been the most common technique in micropatterning, ironically it has not been adopted to produce multifunctional hydrogel microparticles, which are highly useful for bioassays. We address this issue by developing a negative photoresist-like polymer system, which is basically comprised of polyethylene glycol (PEG) triacrylate as cross-linking units and long-chain polyvinylpyrrolidone (PVP) as the supporting scaffold. We leverage standard lithography to manufacture multilayer microparticles that are intrinsically hydrophilic, low-autofluorescent, and chemically reactive. The versatility of the microparticles is demonstrated to be color-encoded, pore-controllable, bioactive, and potentially used as a DNA bioassay.