Cu2O-Based Electrochemical Biosensor for Non-Invasive and Portable Glucose Detection

Abstract

Electrochemical voltammetric sensors are some of the most promising types of sensors for monitoring various physiological analytes due to their implementation as non-invasive and portable devices. Advantages in reduced analysis time, cost-effectiveness, selective sensing, and simple techniques with low-powered circuits distinguish voltammetric sensors from other methods. In this work, we developed a Cu2O-based non-enzymatic portable glucose sensor on a graphene paste printed on cellulose cloth. The electron transfer of Cu2O in a NaOH alkaline medium and sweat equivalent solution at very low potential (+0.35 V) enable its implementation as a low-powered portable glucose sensor. The redox mechanism of the electrodes with the analyte solution was confirmed through cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy studies. The developed biocompatible, disposable, and reproducible sensors showed sensing performance in the range of 0.1 to 1 mM glucose, with a sensitivity of 1082.5 ± 4.7% µA mM−1 cm−2 on Cu2O coated glassy carbon electrode and 182.9 ± 8.83% µA mM−1 cm−2 on Cu2O coated graphene printed electrodes, making them a strong candidate for future portable, non-invasive glucose monitoring devices on biodegradable substrates. For portable applications we demonstrated the sensor on artificial sweat in 0.1 M NaOH solution, indicating the Cu2O nanocluster is selective to glucose from 0.0 to +0.6 V even in the presence of common interference such as urea and NaCl.

Highly Sensitive and Selective Detection of Formaldehyde via Bio-Electrocatalysis over Aldehyde Dehydrogenase

“…It has been proposed that the HCHO oxidation reaction plays a key role in enhancing the electron transfer efficiency of the Cu(III) reduction and Cu(II)/Cu(I) transition accordingly. , Therefore, we proposed the mechanism of HCHO sensing based on bio-electrocatalytic activity of ALDH and Cu electrodes could be described as follows 2 normalC normalu normalI normalI normalI normalO normalO normalH + normalH normalC normalH normalO + normalH 2 normalO true → normalA normalL normalD normalH 2 normalC normalu normalI normalI false( normalO normalH false) 2 + normalH normalC normalO normalO normalH …”

“…It has been proposed that the HCHO oxidation reaction plays a key role in enhancing the electron transfer efficiency of the Cu­(III) reduction and Cu­(II)/Cu­(I) transition accordingly. , Therefore, we proposed the mechanism of HCHO sensing based on bio-electrocatalytic activity of ALDH and Cu electrodes could be described as follows …”

“…It has been proposed that the HCHO oxidation reaction plays a key role in enhancing the electron transfer efficiency of the Cu(III) reduction and Cu(II)/Cu(I) transition accordingly. 21,22 Therefore, we proposed the mechanism of HCHO sensing based on bio-electrocatalytic activity of ALDH and Cu electrodes could be described as follows In addition, the ion chromatography test was further performed on the electrolyte after CV scans (Figure S4), showing the formation of formic acid. The generation of Cu(I), Cu(II), and formate as products further proved the bioelectrocatalytic mechanism of HCHO detection.…”

Recent innovations in the technology and applications of low-dimensional CuO nanostructures for sensing, energy and catalysis

“…One more technology for the fabrication of copper oxide-based biosensors for non-invasive glucose detection was developed recently by Franco et al 173 In order to fabricate the sensor, the authors first print-coated electrodes onto fabric that was made of cellulose using a paste containing graphene. Cellulose is an excellent substrate material as it offers an attractive combination of minimal cost and toxicity, abundance, excellent compatibility with living systems, the ability to be disposed of and degrade naturally, as well as excellent porosity that maximises the contact area between the sensor and the biofluid.…”

Metal Nanoclusters in Point-of-Care Sensing and Biosensing Applications

“…Considering the high stability of copper oxide than copper NCs, investigation in this field can open a new landscape to fill the gaps correlated to low stability and reduced optical properties of copper NCs, especially in biological fluids where various types of small and macromolecules can reduce their resistance and emission properties. Cu 2 O-based nanoparticles are popularly employed as electrosensitizers in electrochemical, ECL, and PEC point-of-care systems. ,, Yin et al reported the application of Cu/Cu 2 O NCs for glucose sensing. In this strategy, Cu/Cu 2 O NCs are employed as an electrocatalyst to enhance the oxidation rate of glucose, leading to increased current and then the detection sensitivity using the amperometry technique.…”