Immobilization of porphyrins in hydrogels for optical sensing

This paper describes a new method for the immoblization of metalloporphyrin molecules for optical oxygen sensing. The porphyrin molecules have an acrylamide group attached allowing the porphyrin indicator to be covalently bound within a hydrogel polymer. Two hydrogel monomers: hydroxyethylmethylacrylamide (HEMA) and acrylamide have been investigated to assess their suitability as host polymers for the porphyrins. The photophysics of both the base and Platinum porphyrin: tetra porphyrin are discussed. Platinum tetra porphyrin bound in a hydrogel polymer using HEMA as the monomer unit was found to have a good sensitivity to oxygen.