Phenol biosensor based on hydrogel microarrays entrapping tyrosinase and quantum dots

This paper describes the use of microarray-based biosensor system for the determination of phenol. Microarrays based on poly(ethylene glycol)(PEG) hydrogel were prepared by photopatterning of a solution containing PEG diacrylate (PEG-DA), photoinitiator, tyrosinase, and CdSe/ZnS quantum dots (QDs). During photo-induced crosslinking, tyrosinase and QDs were entrapped within the hydrogel microarrays, making the hydrogel microarray fluorescent and responsive to phenol. The entrapped tyrosinase could carry out enzyme-catalyzed oxidation of phenol to produce quinones, which subsequently quenched the fluorescence of QDs within hydrogel microarray. The fluorescence intensity of the hydrogel microarrays decreased linearly according to phenol concentration and the detection limit of this system was found to be 1.0 μM. The microarray system presented in this study could be combined with a microfluidic device as an initial step to create a phenol-detecting "micro-total-analysis-system (μ-TAS)".