Efficient and Facile Fabrication of Glucose Biosensor Based on Electrochemically Etched Porous HOPG Platform.

Herein, a uniform porous highly oriented pyrolytic graphite (HOPG) electrode was prepared via diazonium salt assisted electrochemical etching method and firstly utilized to immobilize enzymes for the construction of a high-performance glucose biosensor. The formation mechanism and morphology structure of the porous HOPG electrode were investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) characterizations. The glucose oxidase (GOx) was functionalized with pyrene groups and then immobilized on the porous HOPG substrate through π-π stacking interactions and hydrogen bonding. As a result, eight times higher oxidation current density can be obtained for a given glucose concentration for the porous HOPG electrode than the pristine one. Detection limit of 5 μM for glucose was achieved for the as-fabricated biosensor. It was obtained that 78 % biocatalytical activity of GOx can be retained after the pyrene functionalization and 65.7 % one can even be maintained after four weeks, which confirmed the high efficiency and good stability of the as-prepared biosensor. What's more, it can be anticipated that various other enzymes can be loaded into this porous HOPG platform using the same enzyme modification methodology for the construction of efficient biosensors. [ABSTRACT FROM AUTHOR]