Structure and Electrochemical Properties of Electrocatalysts for NADH Oxidation

Abstract

NADH electrocatalysts have been an area of study for over 3 decades. Polyazines have been popular electrocatalysts of choice for NADH oxidation for both sensors and biofuel cell applications. However, little is known about the structure and function relationship between these polyazines and their ability for NADH oxidation. In this paper, we utilize XPS, SEM, and NMR to evaluate the structure of polyazines and relate that to their electrochemical properties.

Preparation and electrochemical and electrochromic properties of wrinkled poly(N-methylthionine) film

“…The positively charged nitrogen atom will pull the bonding electrons toward its nucleus, which in turn enhances the binding energy of C1s. The C¼O bonds originate from the hydrolysis of quinoid-imine units in the backbone of PNMTh, similarly to those of polyaniline [48] and poly (methylene blue) [49].…”

Direct electrochemistry and Os-polymer-mediated bioelectrocatalysis of NADH oxidation by Escherichia coli flavohemoglobin at graphiteelectrodes

“…To overcome these problems modified electrodes were extensively used to reduce the overpotential of the reaction and to maintain fast reaction kinetics. Modified electrodes for NADH oxidation exploit conductive polymers and different types of mediators such as quinones, diimines, flavins, phenothiazines and phenoxazine derivatives, also polymerized (Bartlett and Simon, 2003;Bartlett et al, 1991;Gorton, 1986;Gorton andDominguez, 2002, 2007;Rincon et al, 2010;Sandström et al, 2000). Another approach involves bioelectrocatalytic oxidation of NADH, however, in practice just a few flavoenzymes were successfully applied for direct (unmediated) NADH oxidation (Barker et al, 2007;Kobayashi et al, 1992;Reeve et al, 2012;Zu et al, 2003); otherwise, enzyme wiring to electrodes by a suitable redox mediator was used (Antiochia and Gorton, 2007;Tasca et al, 2008;Tsujimura et al, 2002a).…”

Glutamate sol-gel amperometric biosensor based on co-immobilised NADP+ and glutamate dehydrogenase

“…According to Rincon and col. [4], the com mercially available methylene green usually contains methylene blue impurities that become apparent in the initial voltammetric scan of the polymerization procedure. Thus, two initial potential peaks at ⎯0.020 and -0.168 V corresponding to MG and me thylene blue oxidations, and two cathodic peaks at ⎯0.080 and -0.227 V were observed (Fig.…”

“…More than 300 dehydrogenase enzymes require the nicotinamide cofactor (NAD(P) + /NAD(P)H) for prop er activity and thus co immobilization procedures are of paramount importance to circumvent the drawback of the continuous new addition of the cofactor [4,5]. At bare electrodes surface overpotentials (≈1 V) to regener ate the cofactor are needed, the oxidation step is partially irreversible and leads to electrode passivation thus reduc ing the useful lifetime of the biosensor.…”