Construction and application of the amperometric uric acid biosensors based on the covalent immobilization of uricase by different strategies
Abstract
In this work, a promising combination of a biosensor based on the enzymatic mini-reactor with the detection principle of four-electron reduction of the consumed oxygen at highly negative potential has been developed for uric acid determination using flow injection analysis. The construction of the biosensor provides a spatial segregation of the biorecognition (uricase-based mini-reactor) and detection (tubular detector of silver solid amalgam (TD-p-AgSA)) parts.
To find out the most appropriate enzyme immobilization protocol, three different strategies of the covalent attachment for uricase from Bacillus fastidiosus have been compared. It was found that the biosensor with the mini-reactor based on the covalent attachment of uricase via glutaraldehyde to -NH functionalized 2mesoporous silica powder MCM-41 showed extremely high stability (>1 year) and reusability (at least 600 measurements) The biosen-sor's practical applicability was confirmed by successful determin-ation of uric acid in human urine.