Electrochemically Induced Free‐Radical Polymerization for the Fabrication of Amperometric Glucose Biosensors

Electrochemically induced free radical polymerization was employed for the fabrication of amperometric glucose biosensors. Based on the electrochemical reduction of persulfate anion, an ultrathin poly(acrylic acid) (PAA) hydrogel coating was generated on both the bare and glucose oxidase (GOD) crosslinked platinum electrodes in a neutral phosphate buffer solution under a low ionic strength condition. This electrosynthetic approach offers a flexible and controllable way to prepare functional coatings for biosensors under a wide range of highly biocompatible conditions, significantly different from other electropolymerization technologies that usually cause the enzyme deactivation. Negatively charged PAA hydrogel coating not only results in a biosensor with good permselectivity and long‐term stability, but also remarkably enhances its sensitivity by improving the oxygen recycle supply and the enzyme activity. Combined with a simple drop‐evaporation procedure to control the GOD loading, the present method offers a versatile and biocompatible way for fabricating highly sensitive biosensor.