Electrochemical Biosensors in Point‐of‐Care Devices: Recent Advances and Future Trends

Abstract

The use of biosensors in point‐of‐care (POC) testing devices has attracted considerable attention in the past few years, mainly because of their high specificity, portability, and relatively low cost. Coupling these devices with miniaturized electrochemical transducers has shown great potential toward simple, rapid, and cost‐effective analysis that can be performed in the field, especially for healthcare, environmental monitoring, and food quality control. For this reason, the number of publications in this field has grown exponentially over the past decade, making it a trending topic in current research. Although great improvement has been achieved in the field of electrochemical biosensing, there are still some challenges to overcome, especially concerning the improvement of sensing materials and miniaturization. In this Review, we summarize some of the most recent advances achieved in POC electrochemical biosensor applications, focusing on new materials and modifiers for biorecognition developed to improve sensitivity, specificity, stability, and response time.

Engineering of Au/Ag Nanostructures for Enhanced Electrochemical Performance

“…The Au/Ag NC sample in conjunction with the G carbon matrix support was used to modify the working electrode on the SPCE, and was utilized here to represent the different nanostructures used in the study (Au NP, Au/Ag NB, and Au/Ag NC). The electrochemical analyses were performed using the Fe(CN) 6 3−/4− redox probe.…”

“…In this study, we evaluated the electrochemical performance of different Au/Ag nanostructures toward the direct determination of the Fe(CN) 6 3−/4− redox probe using CV. Shown in Scheme 1 is an illustration of the nanostructure architecture and electrochemical system used in our study.…”

“…For the CV experiments, 5 mM Fe(CN) 6 3−/4− solutions were prepared in PBS (1x, pH 7.4) and 0.1 M KCl (as supporting electrolyte) and scanned between −1.0 V to 1.0 V at a scan rate of 200 mV/s at room temperature.…”

“…[1][2][3][4] Moreover, engineered electrocatalytic nanomaterials provide a means to develop simple-to-contruct 5 electrochemical sensors that can be used for routine point-of-care health monitoring and diagnostics. 6,7 However, for most biomedical applications, a next generation sensor platform technology will require significant improvements in the nanomaterials' properties to facilitate lower detection limits and higher sensitivities under lower costs for mass production. 8,9 An effective electrochemical sensor relies heavily on the surface architecture of the working electrode in order to allow the recognition process to occur under short response time, achieve good signal-tonoise (S/N) ratio, and detect the analyte of interest at low limits of detection (LOD) with high selectively.…”

“…In addition, we explored the effects of nanostructuring with graphene nanoplatelets (G) as carbon matrix support, and the modification of the surface chemistry with β-cyclodextrin, on the electrochemical performance of the Au/Ag nanomaterials. 6 ], 99%}, potassium chloride (KCl, 99%), Nafion 117 solution, hydrogen tetrachloroaurate(III) hydrate (HAuCl 4 · xH 2 O, 99.995%), cortisol (98%), β-cyclodextrin (97%), 2-propanol (99.5%), anhydrous ethylene glycol (99.8%), sodium sulfide (Na 2 S), polyvinylpyrrolidone (PVP, MW 55,000), silver nitrate (AgNO 3 ), trisodium citrate dihydrate (99%), hydrochloric acid (37%), nitric acid (70%) and the Au and Ag standards for elemental analyses were purchased from Sigma-Aldrich Co., USA. The phosphate-buffered saline (PBS) solution (10x, pH 7.4) used in the electrochemical measurements was purchased from Fisher Scientific Co., USA.…”