Optical Waveguide Spectroscopy for the Investigation of Protein-Functionalized Hydrogel Films

This article reports the implementation of optical waveguide spectroscopy (OWS) for the quantitative time‐resolved observation of changes in the swelling behavior and mass density of protein‐functionalized hydrogel films. In the experiment, a thin film of an N‐isopropylacrylamide (NIPAAm)‐based polymer that supported optical waveguide modes is attached to a metallic sensor surface. IgG molecules are in situ immobilized in this gel by using novel coupling chemistry with a charge‐attraction scheme based on a tetrafluorophenol sulfonate active ester. The anti‐fouling properties of the functionalized hydrogel network and the kinetics of the affinity binding of protein molecules in the gel are investigated. Optical waveguide spectroscopy (OWS) is used here for the quantitative observation of changes in the swelling behavior and mass density of protein‐functionalized hydrogel films. A thin film of an N‐isopropylacrylamide‐based polymer that supported optical waveguide modes is attached to a metallic sensor surface and IgG molecules are immobilized in situ. The anti‐fouling properties of the functionalized hydrogel network and the kinetics of affinity binding of protein molecules in the gel have been investigated.