A disposable electrochemical biosensor for l-DOPA determination in undiluted human serum

A disposable electrochemical biosensor for the determination of L-DOPA in undiluted human serum is described. It is based on the use of a carbon nanotubes-modified screen printed electrode covered with an electropolymerized poly(thionine) film and an outer cross-linked layer containing tyrosinase. Further coverage of the sensor with a Nafion layer allows its use directly in human serum, obviating the need for sample pretreatment. The sensor exhibited a linear behavior in the 0.8–22 μM concentration range and offers promise for decentralized clinical testing of L-DOPA.