Green synthesis of starch-capped Cu2O nanocubes and their application in the direct electrochemical detection of glucose

Glucose determination is an essential procedure in different fields, used in clinical analysis for the prevention and monitoring of diabetes. In this work, modified carbon paste electrodes with Cu2O nanocubes (Cu2O NCs) were developed to test electrochemical glucose detection. The synthesis of the Cu2O NCs was achieved by a green method using starch as the capping agent, obtaining cubic-like morphologies and particle sizes from 227 to 123 nm with increasing amounts of the capping agent, as corroborated by electron microscopy analysis. Their crystalline structure and purity were determined by X-ray diffraction. The capability of starch as a capping agent was verified by Fourier-transform infrared spectroscopy, in which the presence of functional groups of this biopolymer in the Cu2O NCs were identified. The electrochemical response to glucose oxidation was determined by cyclic voltammetry, obtaining a linear response of the electrical current as a function of glucose concentration in the range 100–700 μM, with sensitivities from 85.6 to 238.8 μA mM−1 cm−2, depending on the amount of starch used in the synthesis of the Cu2O NCs.The authors thank the i-Link+2019 program between CSIC and Tecnologico de Monterrey (ref. LINKB20024 “NANOBIO-ROJA”) for nancial support. LM acknowledges nancial support from EC through ERC-2013-SYG-610256 and “Comunidad de Madrid” and the European Structural Funds (FotoArt-CM project S2018/NMT-4367). The authors also acknowledge the service from the MiNa Laboratory at IMN, which is funded by Comunidad de Madrid (project S2018/NMT-4291TEC2SPACE), MINECO (project CSIC13-4E-1794), and EU (FEDER, FSE). AM acknowledges the Spanish Ministry of Science through the Ramon y Cajal programme (RYC2018-024561-I), the Regional government of Aragon (DGA E13_20R), the National Natural Science Foundation of China (NFSC-21850410448, NSFC21835002) and the Centre for High-resolution Electron Microscopy (CħEM), supported by SPST of ShanghaiTech University under contract No. EM02161943. We also thank the School of Engineering and Sciences at Tecnologico de Monterrey for partial funding provided through the Research Chair of Photonics and Quantum Systems and the Department of Science (Chemistry and Nanotechnology) at Tecnologico de Monterrey for access to laboratories and characterization equipment.Peer reviewe