Enzymatically and Combinatorially Generated Array-Based Polyphenol Metal Ion Sensor

Phenolic polymers were synthesized via soybean hull peroxidase catalysis and used as metal-based sensor components in a polymer array. A sensor array for Fe^3+, Cu^2+, Co^2+, and Ni^2+ has been developed consisting of 15 phenolic homopolymers and copolymers generated from five phenolic monomers by peroxidase-catalyzed oxidative polymerization. Sensing was based on the change of intrinsic polyphenol fluorescence upon addition of a metal ion or a metal ion mixture to an aqueous suspension of a polyphenol. Importantly, the fluorescence response of copolymers differed, in some cases dramatically, from the constituent homopolymers and was dependent upon the relative ratio of monomers that comprise the polymer. This finding suggests that an extremely broad range of sensor arrays can be generated from a limited number of phenolic monomers. Using a statistical analysis, histograms constructed for the four different metal ions yielded unique fingerprints of the array response and can be used to identify specific metal ions.