Dual signal glucose reporter based on inverse opal conducting hydrogel films

Abstract

A novel glucose responsive hydrogel film possessing inverse opal structure and conducting property was developed, based on the principle of enzyme-catalytic redox reaction. The film can report glucose concentration via optical and electrochemical signals, respectively. To fabricate the sensor film, SiO₂ crystalline colloidal array was utilized as a sacrificed template to endow the polyacrylamide(PAAm) hydrogel with non-closed-packed inverse opal structure, then conductive polymer (CP) poly(3,4-ethylenedioxythiophene) PEDOT was in situ chemically oxypolymerized to form interpenetrated network (IPN) within the hydrogel. The supporting matrix was activated by partial hydrolysis of amide groups on the backbone, to serve as bonding sites for glucose oxidase (GOx) and ion responsive elements. The changes in the hydrogel microenvironment caused by the catalytic product of glucose induced shrinkage of the hydrogel and a corresponding blue shift of the reflection peak of the film. Meanwhile, the hydrogel acted as a flexible amperometric electrode to sense current change. Linear response upon concentration of glucose ranged from 1 mM to 12 mM. Glucose was exhibited optically and electrically confirming a mutual regulation capacity to achieve better anti-interference performance.