Electrochemical Detection of NADH, Cysteine, or Glutathione Using a Caffeic Acid Modified Glassy Carbon Electrode

Abstract

A modified electrode was prepared using electrodeposition methods to immobilize caffeic acid (CAF) onto the surface of a glassy carbon electrode (GCE) to create a polymer suitable for biosensor development. The polymer film coverage of the surface bound species was further optimized using electrodeposition methods, thus increasing the surface coverage to ca. 10−9 mol cm−2. Using cyclic voltammetry, the modified carbon electrode was used to facilitate and observe the electrocatalytic oxidation of coenzymes such as NADH, cysteine, and glutathione at different concentrations. A calibration curve was determined in each case within the concentration range; 300 nM to 10 mM, with the limits of detection (LOD) of 246 µM, 99 µM, 2.2 µM for NADH, cysteine, and glutathione respectively.

Development of an Electrochemical Sensor for NADH Determination Based on a Caffeic Acid Redox Mediator Supported on Carbon Black

“…In this respect, it has to be evidenced that the electrochemical deposition is the procedure generally reported by the literature [5][6][7]25]. However, by considering that the mechanisms proposed for CFA deposition on carbon surfaces are based on Michael addition, the drop-casting method represents an alternative deposition approach, which gives the CFAads/CB/SPE sensor system.…”

“…One of the main problems in the realization of efficient amperometric sensors lies in the stability of the anchoring of a similar soluble redox mediator on the electrode surface. Stable chemical bonds can be obtained by using some o-quinone derivatives, mainly consisting of 3,4-dihydroxybenzaldehyde [4], caffeic acid (CFA; see Figure 1) [5,6] or chlorogenic acid [7]. They all undergo reversible charge transfer processes, according to the mechanism described in Figure 1 for the case of CFA.…”

“…On the other hand, low pH values partially or completely prevent the reaction, due to the protonation of carboxylic groups on the carbon electrode. As an example, in the case of CFA, the highest coverage is obtained at pH 4 [5,6], i.e., a value slightly lower than pKa (= 4.62). In this case, however, the literature does not agree in defining whether the nucleophilic attack involves o-quinone produced during the electrochemical oxidation (blue-colored in Figure 1) [5] or the Michael acceptor external to the o-hydroquinone ring (red-colored in Figure 1) [6].…”

Single-walled carbon nanotubes covalently functionalized with polytyrosine: A new material for the development of NADH-based biosensors

“…Some redox mediators have been used as shuttle for the electron transport from NADH to the electrode surface (Canevari et al, 2011;Dilgin et al, 2013;Gamella et al 2010;Lee and Compton, 2013;Mao et al, 2011;Nassef et al, 2006;Prieto-Simon and Fábregas, 2004;Revenga-Parra et al, 2012;Zanardi et al, 2015) reducing, in this way, the energy necessary for NADH oxidation and improving the efficiency of the electrocatalytic oxidation process. The modification of electrodes with carbon nanomaterials (Gasnier et al, 2013;Sun et al, 2013;Wang et al, 2012), nanoparticles Jena and Raj, 2006;Sharifi et al, 2013) or hybrid nanomaterials (Agüí et al, 2009;Govindhan et al, 2015;Hosseini et al, 2014;Mundaca et al, 2012;Teymourian et al, 2013;Tiwari and Gupta, 2014) have demonstrated to be highly successful.…”

Selective electrochemical detection of thiol biomarkers in saliva using multiwalled carbon nanotube screen-printed electrodes

“…Electrochemical method in the form of point-of-care sensors has its major advantages over the mentioned methodologies as measurements can be quick, easy, and cheap. One common type of point-to-care sensors is that based on carbon screen-printed electrode [20][21][22][23]. It is best suited for applications that require high throughput testing, such as clinical testing [22][23][24].…”