Electrochemical Biosensor Based on Integrated Assembly of Dehydrogenase Enzymes and Gold Nanoparticles

Abstract

Development of a highly sensitive nanostructured electrochemical biosensor based on the integrated assembly of dehydrogenase enzymes and gold (Au) nanoparticle is described. The Au nanoparticles (AuNPs) have been self-assembled on a thiol-terminated, sol-gel-derived, 3-D, silicate network and enlarged by hydroxylamine seeding. The AuNPs on the silicate network efficiently catalyze the oxidation of NADH with a decrease in overpotential of approximately 915 mV in the absence of any redox mediator. The surface oxides of AuNP function as an excellent mediator, and a special inverted "V" shape voltammogram at less positive potential was observed for the oxidation of NADH. The AuNP self-assembled sol-gel network behaves like a nanoelectrode ensemble. The nanostructured electrode shows high sensitivity (0.056 +/- 0.001 nA/nM) toward NADH with an amperometric detection limit of 5 nM. The electrode displays excellent operational and storage stability. A novel methodology for the fabrication of a NADH-dependent dehydrogenase biosensor based on the integration of dehydrogenase enzyme and AuNPs with the silicate network is developed. The enzymatically generated NADH is, in turn, electrocatalytically detected by the AuNPs on the silicate network. The integrated assembly has been successfully used for the amperometric biosensing of lactate and ethanol at a potential of -5 mV. The biosensor is very stable and highly sensitive, and it has a fast response time. The excellent performance validates the integrated assembly as an attractive sensing element for the development of new dehydrogenase biosensors.

Gold nanoparticle-based biosensors

“…The catalytic effect of GNPs was explained by the oxidation effect of surface oxides, which originated from the unusually oxidation of GNPs at low potential. A more detailed study similar to this case was reported by the same group later [115]. Nitric oxide electrochemical sensors fabricated on GNPs modified platinum microelectrode [116] or dense GNP film modified electrode [117] were also reported to be based on the catalytic oxidation of GNPs.…”

Nanomaterials for biomedical applications

“…GNP based glucose biosensors have a detection limit of 0.18 μM (Andreescu & Luck 2008). A NADH sensor based on GNPs shows 780 mV potential decreases without any electron transfer mediators (Jena & Raj 2006). Piezoelectric biosensors are principally based on changes in mass.…”

Gold Nanoparticles-Enhanced Amperometric Tyrosinase Biosensor Based on Three-Dimensional Sol-Gel Film-Modified Gold Electrodes

“…Currently, a (3-mercaptopropyl)-trimethoxysilane (MPTS) sol-gel-derived three-dimensional network is attractive in the development of sensing devices. The thiol tail groups of an MPTS three-dimensional network is able to be covalently bound onto the surface of Au through cleavage of the S-H bond 17 and the formation of a Au-S bond, 18 while AuNPs can be conveniently self-assembled on the thiol groups present in the network. MPTS sol-gel and AuNPs-based materials have been used for the immobilization of enzymes, such as dehydrogenase, 17,19 bilirubin oxidase, 20 lactate oxidase 21 and glucose oxidase, 22 for the development of biosensors.…”