Review of Electrochemical Sensors and Biosensors Based on First-Row Transition Metals, Their Oxides, and Noble Metals Nanoparticles

The use of electrochemical sensors for sensitive disease diagnosis and detecting various species with pharmacological, therapeutic, industrial, food-related, and environmental origins is now widely accepted. A catalytic or binding event resulting from the sensor’s electroactive component recognizing its analyte creates an electrical signal proportionate to the analyte concentration, which is then monitored by a transducer. The development of morphologically distinct metal and metal oxide nanoparticles formed from first-row transition elements (Mn, Cr, Fe, Co, Ti, Ni, Cu, Zn) and noble metals (Pt, Au, Ag, Pd) is described in this review. The effect of these metal nanoparticles has been studied using Tetracyanoquinodimethane (TCNQ), Ferrocene, and other organic compounds as electroactive species using carbon paste-modified electrodes. Electroanalytical sensors, mostly based on ferrocene, are exceedingly sensitive, selective, affordable, and for detecting numerous biomolecules like glucose, dopamine, NADH, ascorbic acid, and a few dyes and are simple to build. In recent decades, charge transfer organic species-based chemosensors have become a prominent study area. This paper outlines current developments in electrochemical biosensors based on transition metal nanoparticles, covering glucose, ascorbic acid, uric acid, and other inorganic and organic analytes. The importance of transition metal and transition metal oxide nanoparticles as potential electrode modifiers for developing sensors is highlighted. A discussion of the present problem and possible solutions, and plausible future directions marks the review’s conclusion.