Facile immobilisation of glucose oxidase onto gold nanostars with enhanced binding affinity and optimal function

Gold nanoparticles provide a user-friendly and efficient surface for immobilisation of enzymes and proteins. In this paper, we present a novel approach for enzyme bioconjugation to gold nanostars (AuNSs). AuNSs were modified with L-cysteine (Cys) and covalently bound to N-hydroxysulfosuccinimide (NHS)-terminated glucose oxidase (GOx) to fabricate a stable and sensitive AuNSs-Cys-GOx bioconjugate complex. Observed, were: 1) Increased attachment affinity without protein absorption onto the AuNSs surface. 2) Good dispersity in buffer suspension, as well as stability in high ionic environments. 3) Greater sensitivity in the measuring of low concentrations of glucose based on plasmonic and colorimentric detection. Such a novel approach for enzyme immobilisation can lead to AuNSs-Cys-GOx bioconjugate complexes that can be used as catalytic nanodevices in nanobiosensors based on oxidases in biomedical applications.