Superoxide sensor based on cytochrome c immobilized on mixed-thiol SAM with a new calibration method

Simultaneous use of electrochemistry and chemiluminescence to detect reactive oxygen species produced by human neutrophils

“…•-sensitive gold electrodes Three types of O 2 •-sensitive biosensors were prepared using two different redox proteins, azurin (Shleev et al, 2006) and cyt c (Ge and Lisdat, 2002;Manning et al, 1998) Prior to bio-modification gold electrodes were rinsed thoroughly with Millipore water. The first type of biosensor, based on azurin adsorbed on the DTSSP-modified gold electrode (azurin-DTSSP electrode), was prepared in accordance with our previous studies (Shleev et al, 2006).…”

“…The calibration of the electrodes was performed using chemically or enzymatically produced superoxide as described elsewhere (Ge and Lisdat, 2002;Shleev et al, 2006;Tammeveski et al, 1998). Basic electrochemical characteristics of the biosensors used in the present study are listed in Table 1.…”

Electrocatalytic evaluation of DNA damage by superoxide radical for antioxidant capacity assessment

“…Therefore, overproduction of ROS can be dangerous for cells [2]. The superoxide anion radical (O ÅÀ 2 ) is the primary component of ROS and the most abundant radical in biological systems, resulting from the single-electron reduction of oxygen [3]. This cytotoxic species is enzymatically produced by xanthine oxidase (XOD), a metalloenzyme that catalyzes the oxidation of hypoxanthine and xanthine to uric acid generating O ÅÀ 2 during the respiratory burst of phagocytic cells (Eq.…”

“…Electrochemical biosensors use two main sources of ROS: OH Å and O ÅÀ 2 . The former can be generated photocatalytically [7] or by Fenton reaction in DNA-based antioxidant sensors [8,9], and the latter is mostly enzymatically [2,10,11] but also chemically [3,12,13] or electrochemically [14] formed for the determination of both superoxide radical and AOC. Sensors based on O ÅÀ 2 commonly rely on the immobilization of cytochrome c, which is reduced by superoxide radical, on gold [2][3][4], carbon [15] or screen printedAu-electrode [16] surfaces, where it is reoxidized.…”

“…The former can be generated photocatalytically [7] or by Fenton reaction in DNA-based antioxidant sensors [8,9], and the latter is mostly enzymatically [2,10,11] but also chemically [3,12,13] or electrochemically [14] formed for the determination of both superoxide radical and AOC. Sensors based on O ÅÀ 2 commonly rely on the immobilization of cytochrome c, which is reduced by superoxide radical, on gold [2][3][4], carbon [15] or screen printedAu-electrode [16] surfaces, where it is reoxidized. To enhance the electrical contact between cytochrome c and the electrode and to increase the surface coverage of this compound, several immobilization strategies have been proposed mostly based on SAMs of thiols of different length [2][3][4]15] and hemin modified electrodes [17].…”