GNP-CeO.sub.2- polyaniline hybrid hydrogel for electrochemical detection of peroxynitrite anion and its integration in a microfluidic platform

• Published in: Mikrochimica acta (1966) Vol. 188; no. 12
• Main Authors: Kumar, Vijayesh, Matai, Ishita, Kumar, Ankit, Sachdev, Abhay
• Format: Journal Article
• Language: English
• Published: Springer 01-12-2021
• Subjects: Electric properties; Electron transport; Graphene
• ISSN: 0026-3672
• DOI: 10.1007/s00604-021-05105-4

Peroxynitrite anion (ONOO.sup.-) is an important in vivo oxidative stress biomarker whose aberrant levels have pathophysiological implications. In this study, an electrochemical sensor for ONOO.sup.- detection was developed based on graphene nanoplatelets-cerium oxide nanocomposite (GNP-CeO.sub.2) incorporated polyaniline (PANI) conducting hydrogels. The nanocomposite-hydrogel platform exhibited distinct synergistic advantages in terms of large electroactive surface coverage and providing a conductive pathway for electron transfer. Besides, the 3D porous structure of hydrogel integrated the GNP-CeO.sub.2 nanocomposite to provide hybrid materials for the evolution of catalytic activity towards electrochemical oxidation of ONOO.sup.-. Various microscopic and spectroscopic characterization techniques endorsed the successful formation of GNP-CeO.sub.2-PANI hydrogel. Cyclic voltammetry (CV) measurements of GNP-CeO.sub.2-PANI hydrogel modified screen-printed electrodes (SPE) were carried out to record the current changes influenced by ONOO.sup.-. The prepared sensor demonstrated a significant dose-dependent increase in CV peak current within a linear range of 5-100 [micro]M (at a potential of 1.12 V), and a detection limit of 0.14 with a sensitivity of 29.35 ± 1.4 [mu]A [mu]M.sup.-1. Further, a customized microfluidic flow system was integrated with the GNP-CeO.sub.2-PANI hydrogel modified SPE to enable continuous electrochemical detection of ONOO.sup.- at low sample volumes. The developed microfluidic electrochemical device demonstrated an excellent sensitivity towards ONOO.sup.- under optimal experimental conditions. Overall, the fabricated microfluidic device with hybrid hydrogels as electrochemical interfaces provides a reliable assessment of ONOO.sup.- levels. This work offers considerable potential for understanding the oxidative stress-related disease mechanisms through determination of ONOO.sup.- in biological samples. Graphical abstract