Flexible Potentiometric Sensor System for Non-Invasive Determination of Antioxidant Activity of Human Skin: Application for Evaluating the Effectiveness of Phytocosmetic Products

Abstract

In contemporary bioanalysis, monitoring the antioxidant activity (AOA) of the human skin is used to assess stresses, nutrition, cosmetics, and certain skin diseases. Non-invasive methods for skin AOA monitoring have certain advantages over invasive methods, namely cost-effectiveness, lower labor intensity, reduced risk of infection, and obtaining results in the real-time mode. This study presents a new flexible potentiometric sensor system (FPSS) for non-invasive determination of the human skin AOA, which is based on flexible film electrodes (FFEs) and membrane containing a mediator ([Fe(CN)6]3–/4–). Low-cost available materials and scalable technologies were used for FFEs manufacturing. The indicator FFE was fabricated based on polyethylene terephthalate (PET) film and carbon veil (CV) by single-sided hot lamination. The reference FFE was fabricated based on PET film and silver paint by using screen printing, which was followed by the electrodeposition of precipitate containing a mixture of silver chloride and silver ferricyanide (SCSF). The three-electrode configuration of the FPSS, including two indicator FFEs (CV/PET) and one reference FFE (SCSF/Ag/PET), has been successfully used for measuring the skin AOA and evaluating the impact of phytocosmetic products. FPSS provides reproducible (RSD ≤ 7%) and accurate (recovery of antioxidants is almost 100%) results, which allows forecasting its broad applicability in human skin AOA monitoring as well as for evaluating the effectiveness of topically and orally applied antioxidants.

Biosensors Based on Phenol Oxidases (Laccase, Tyrosinase, and Their Mixture) for Estimating the Total Phenolic Index in Food-Related Samples

“…Gold electrodes [ 62 , 94 , 95 , 96 , 97 , 98 , 110 ], electrodes with a platinum anode [ 68 , 112 ], indium tin oxide (ITO) coated glass slides [ 70 ], screen-printed carbon electrodes (SPCEs) [ 60 , 64 , 71 , 102 , 103 , 104 , 105 , 111 , 113 , 116 ], glassy carbon electrodes (GCEs) [ 61 , 63 , 67 , 106 , 109 ], sonogel-carbon electrodes (SCEs) [ 65 , 66 , 69 ], and carbon paste electrodes (CPEs) [ 99 , 100 , 101 , 107 ] were used for fabricating electrochemical PO-based biosensors for assessing TPI in FRSs. The list of carbon-containing electrodes could be supplemented by carbon cloth and carbon paper, which are widely used in the development of potentiometric [ 147 ], voltammetric, and amperometric [ 148 ] (bio)sensors. Commercially available disposable SPCEs have a miniature planar configuration that enables them to perform electrochemical measurements in the single-drop mode [ 102 , 103 , 104 , 105 , 111 ].…”

Potentiometric sensor system based on modified screen-printed electrodes for determining antioxidant activity

“…Brainina et al proposed potentiometric sensor systems (PSSs) to evaluate AOA coupled with [Fe(CN)6] 3-/4-, which used a new quasi-reference electrode with a stable potential in an environment with variable ferro/ferricyanide ion content [15][16][17][18]. The developed PSSs differed in the nature of the indicator electrode.…”

“…A screen-printed carbon electrode droplet-modified with gold nanoparticles was effective in assessing skin AOA using a microporous membrane [17], but its use in a stirred solution could serve to reduce the robustness of the analysis. A film electrode based on a carbon veil made it possible to obtain reliable results both in contact with a microporous membrane and in a stirred solution [18]. However, the manufacturing technology of this electrode (hot lamination) was different from the manufacturing technology of the reference electrode (screen printing), which made it difficult to integrate the two electrodes on a single substrate.…”

Carbon Paper Modified with Functionalized Poly(diallyldimethylammonium chloride) Graphene and Gold Phytonanoparticles as a Promising Sensing Material: Characterization and Electroanalysis of Ponceau 4R in Food Samples

“…So far, a few CP-based electrochemical sensors have been developed. They are described in the review [ 22 ] and some original articles that have not been included in this review [ 23 , 24 , 25 ]. Quite recently, the first article has been published that presents a novel voltammetric sensor based on carbon paper modified by graphite powder for the highly sensitive and selective determination of sunset yellow and tartrazine [ 26 ].…”