Analysis of Dopamine and Tyrosinase Activity on Ion-Sensitive Field-Effect Transistor (ISFET) Devices

摘要

Dopamine (1) and tyrosinase (TR) activities were analyzed by using chemically modified ion-sensitive field-effect transistor (ISFET) devices.In one configuration,a phenylboronic acid functionalized ISFET was used to analyze 1 or TR.The formation of the boronate-1 complex on the surface of the gate altered the electrical potential associated with the gate,and thus enabled 1 to be analyzed with a detection limit of 7X10~(-5) M.Similarly,the TR-in-duced formation of 1,and its association with the boronic acid ligand allowed a quantitative assay of TR to be performed.In another configuration,the surface of the ISFET gate was modified with tyramine or 1 to form functional surfaces for analyzing TR activities.The TR-induced oxidation of the tyramine-or 1-functionalized ISFETs resulted in the formation of the redox-active dopaquinone units.The control of the gate potential by the redox-active dopaquinone units allowed a quantitative assay of TR to be performed.The dopaquinone-function-alized ISFETs could be regenerated to give the 1-modified sensing devices by treatment with ascorbic acid.