Biosensor Array of Interpenetrating Polymer Network with Photonic Film Templated from Reactive Cholesteric Liquid Crystal and Enzyme-Immobilized Hydrogel Polymer

A biosensor array is fabricated using an interpenetrating polymer network consisting of photonic film templated from reactive cholesteric liquid crystal (CLC) and enzyme-immobilized polyacrylic acid (PAA). The solid-state photonic film on the glass substrate is successfully templated by ultraviolet (UV) curing of the reactive CLC mixture of a reactive mesogen mixture of RMM 727 (from Merck) and a nonreactive chiral dopant of (S)-4-cyano-4′-(2-methylbutyl)biphenyl following the extraction of the chiral dopant. The acrylic acid monomer mixed with a cross-linker of tri(propylene glycol) diacrylate is infiltrated into the extracted space of the photonic film, and UV-cured with a photomask to obtain a patterned array-dot film. The interpenetrated cholesteric liquid crystal/hydrogel polymer network (CLC-hydrogel-IPN) array is further functionalized in the individual dots with urease, for a model study of biosensor array applications. The dots of the CLC-hydrogel-IPN array respond independently to the urea by a color change with high sensitivity and stability. Thus, the patterned CLC-hydrogel-IPN can be used as a new biosensor array for cost-effective and easy visual detection without any sophisticated instruments.