Effective immobilization of tyrosinase via enzyme catalytic polymerization of l-DOPA for highly sensitive phenol and atrazine sensing

•Tyrosinase was immobilized via enzyme catalytic polymerization of L-DOPA.•The biosensor exhibits performance superior to most previous reported values.•The resultant biosensor works well both in phenol and atrazine sensing.•The proposed biosensor works well in real water samples determination.

The facile preparation of poly(l-DOPA)-tyrosinase (PDM-Tyr) composite and its application both in substrate (phenol) and inhibitor (atrazine) sensing is reported here for the first time. Effective immobilization of enzyme is realized via in-situ entrapping Tyr in poly(l-DOPA) (PDM), which is formed by Tyr catalytic polymerization of l-DOPA. The Tyr modified electrode is simply prepared by dipping the PDM-Tyr composite on an Au electrode and then covered by Nafion. The thus-prepared Tyr-immobilized electrode exhibits excellent performance superior to most Tyr-based electrochemical biosensors, the sensitivity to phenol is as high as 5122 μA mM−1 in the linear range of 10 nM~1.25 μM, the apparent Michaelis-Menten constant (KMapp) determined as low as 3.13 μM indicates strong substrate binding and high catalytic activity of the immobilized Tyr. The biosensor also works well in atrazine biosensing, with a linear detection range of 50 ppb~30 ppm and a low detection limit of 10 ppb obtained. In addition, the biosensor shows excellent stability, precision, high sensitivity and fabrication simplicity.

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