Electrochemical Study of Selenocystine Reactivity and Reduction at Metallic Surfaces

Abstract

The reduction of seleno-L-cystine is examined on gold and platinum electrodes in aqueous solution. The voltammetric behavior is indicative of a two-step process, in which the metallic substrate is modified by the diselenide analyte prior to observation of diffusionally controlled, proton-coupled electron transfer. X-ray photoelectron spectroscopy confirms the presence of selenium on gold foil samples that have been reductively cycled in selenocystine solution. The selenium-based surface modification, which is accessible through multiple preparation routes, can be removed by anodic stripping and fully restored through subsequent cycling. The described electrochemical approach allows for the analysis of redox-active chalcogen-containing species under physiologically relevant conditions. Results and Discussion Voltammetric Behavior of Seleno-L-cystine on GoldThe voltammetric response of selenocystine on gold features a quasi-reversible redox couple centered at À486 mV vs. Ag/ AgCl. [10] Figure 1 shows a comparison of cyclic voltammograms recorded for increasing selenocystine concentrations (0.2-2 mM) in phosphate buffered saline (PBS, pH 7). For each concentration, the electrode has been reductively cycled (À0.2 to À0.7 V vs. Ag/AgCl) for 100 consecutive scans in the selenium-containing solution to reach a steady signal. [10] The dependence of peak current on concentration is linear (Figure S1), consistent with the measured redox process corre- [a]

Selenium Silk Nanostructured Films with Antifungal and Antibacterial Activity

“…Antimicrobial resistance remains one of the most critical public health concerns, as current medicines used to treat a variety of ailments caused by viruses, fungi, and bacteria become ineffective. − Research into antimicrobial agents that subsequently do not become resistant to such microbes is thus needed to avert this crisis. Several studies have focused on silver nanoparticles for antimicrobial solutions; however, studies have indicated emerging resistance to these materials from bacterial populations as well as toxicity to human cells. − One potential alternative to silver in this role is selenium, a trace element in the human body that is an essential micronutrient often found as selenocysteine, the 21st human amino acid. , Selenium nanoparticles have been shown to exhibit effective antimicrobial properties − against a broad range of microorganisms including Escherichia coli and Candida albicans . Moreover, there has been an increased interest in functionalizing selenium nanoparticles using chitosan, hyaluronic acid, polyethylene glycol (PEG), pectin, and peptides, in order to improve stability and enhance biocompatibility .…”

“…26−28 One potential alternative to silver in this role is selenium, a trace element in the human body that is an essential micronutrient often found as selenocysteine, the 21st human amino acid. 29,30 Selenium nanoparticles have been shown to exhibit effective antimicrobial properties 31−33 against a broad range of microorganisms including Escherichia coli and Candida albicans. 32 Moreover, there has been an increased interest in functionalizing selenium nanoparticles using chitosan, 34 hyaluronic acid, 35 polyethylene glycol (PEG), 36 pectin, 37 and peptides, 38 in order to improve stability and enhance biocompatibility.…”

Selenium Silk Nanostructured Films for Antifungal and Antibacterial Treatments

“…26–28 One potential alternative to silver in this role is selenium, a trace element in the human body that is an essential micronutrient often found as selenocysteine, the 21st human amino acid. 29,30 Selenium nanoparticles have been shown to exhibit effective antimicrobial properties 31–33 against a broad range of microorganisms including Escherichia coli and Candida albicans . 32 Moreover, there has been an increased interest in functionalising selenium nanoparticles using chitosan, 34 hyaluronic acid, 35 polyethylene glycol (PEG), 36 pectin 37 and peptides, 38 in order to improve stability and enhance biocompatibility.…”