Sensitive electrochemical detection of vaccinia virus in a solution containing a high concentration ofl-ascorbic acid

Abstract

Washing processes cannot fully remove interfering species that remain on biosensing surfaces when a sample solution contains a high concentration of interfering species. This study reports an immunosensing scheme employing electroreduction-based electrochemical-chemical (EC) redox cycling that allows sensitive detection of vaccinia virus (VV) in a solution containing a high concentration of L-ascorbic acid (AA). To obtain high signal amplification, an enzymatic reaction by β-D-galactosidase (Gal) is combined with electroreduction-based EC redox cycling by an oxidant. Among the four possible oxidants (KIO3, NaClO, Ag2O, and H2O2), KIO3 shows the highest signal-to-background ratio and is chosen. During an incubation period of 10 min, Gal converts β-D-galactopyranoside into p-aminophenol (AP), which is oxidized to p-quinone imine (QI) by KIO3. When -0.05 V vs. Ag/AgCl is applied to an immunosensing electrode, QI is reduced to AP, and the regenerated AP is then reoxidized by KIO3. The electroreduction-based EC redox cycling is induced. An indium-tin oxide electrode modified with reduced graphene oxide and an applied potential of -0.05 V are used to achieve low and reproducible background currents, slow O2 reduction, and fast electroreduction of QI. KIO3 favorably converts AA into noninterfering species during the incubation period. The detection limit for VV in commercial 50% mandarin juice (AA concentration = 0.7 mM) is 4 × 10(3) plaque-forming unit (PFU) per mL. The new EC redox cycling scheme is promising for sensitive detection of proteins, viruses, and bacteria in solutions containing high concentrations of AA.

Trypsin Detection Using Electrochemical Reduction‐based Redox Cycling

“…Redox cycling involving a signaling species such as electrochemical‐chemical (EC) redox cycling and electrochemical‐enzymatic (EN) redox cycling 5–7 can be used to obtain significantly increased electrochemical reduction signals. In electrochemical reduction‐based EC and EN redox cycling, a signaling species is reduced at the electrode and is then regenerated by an oxidizing agent dissolved in an aqueous electrolyte solution 4,8 . The regenerated signaling species is electrochemically reduced again, and this redox cycling leads to increased electrochemical signal levels.…”

“…In electrochemical reduction-based EC and EN redox cycling, a signaling species is reduced at the electrode and is then regenerated by an oxidizing agent dissolved in an aqueous electrolyte solution. 4,8 The regenerated signaling species is electrochemically reduced again, and this redox cycling leads to increased electrochemical signal levels. To obtain reproducible signal levels and low background levels, oxidizing agents should be stable in aqueous electrolyte solutions, and electrochemically inactive in potential regions where electrochemical measurements are performed.…”

“…However, EC redox cycling involving a signaling species and IO 3 − is not fast. 8 All three cases still have limitations in terms of signal-to-background ratio. Nevertheless, the EN redox cycling involving H 2 O 2 allows for the highest electrochemical signal levels.…”

A Phenazine Hydrochloride for the Selective Detection and Removal of Mercury(ІІ) Ions in Water

“…[11][12][13][14][15][16] Compared with many of the currents techniques for mercury detection (See Supporting Information, Table S1), [17][18][19][20] due to its simplicity, high selectivity, high sensitivity, real-time and low cost, the fluorescent and colorimetric sensor has been provided to more convention. [21][22][23][24] Hg 2 + sensors always have been expected to offer a rapid and simple approach to detect Hg 2 + in the environment and organism. [25][26][27][28][29] In this context, rapid and efficient Hg 2 + dual sensing is urgently needed in pure water.…”

Rapid and Sensitive Electrochemical Detection of Carbaryl Based on Enzyme Inhibition and Thiocholine Oxidation Mediated by a Ruthenium(III) Complex

“…Importantly, many Ru and Os complexes undergo fast outer‐sphere reactions, even at low‐electrocatalytic indium‐tin‐oxide (ITO) electrodes , whereas the redox reactions of most interfering species are slow at ITO electrodes. Therefore, when Ru and Os complexes are combined with ITO electrodes, better signal‐to‐background ratios can be obtained .…”