Wide-ranging research efforts have been directed to prioritize scientific and technological inventions for healthcare monitoring. In recent years, the effective utilization of functional nanomaterials in various electroanalytical measurements realized a rapid, sensitive, and selective detection and monitoring of a wide range of biomarkers in body fluids. Owing to good biocompatibility, high organic capturing ability, strong electrocatalytic activity, and high robustness, transition metal oxide-derived nanocomposites have led to enhancements in sensing performances. The aim of the present review is to describe key advancements of transition metal oxide nanomaterials and nanocomposites-based electrochemical sensors, along with current challenges and prospects towards the development of a highly durable and reliable detection of biomarkers. Moreover, the preparation of nanomaterials, electrode fabrication, sensing mechanism, electrode-bio interface, and performance of metal oxides nanomaterials and nanocomposite-based sensor platforms will be described.

A novel method is developed to fabricate the polypyrrole (PPy) and graphene thin films on electrodes by electrochemical polymerization of pyrrole with graphene oxide (GO) as a dopant, followed by electrochemical reduction of GO in the composite film. The composite of PPy and electrochemically reduced graphene oxide (eRGO)-modified electrode is highly sensitive and selective toward the detection of dopamine (DA) in the presence of high concentrations of ascorbic acid (AA) and uric acid (UA). The sensing performance of the PPy/eRGO-modified electrode is investigated by differential pulse voltammetry (DPV), revealing a linear range of 0.1–150 μM with a detection limit of 23 nM (S/N = 3). The practical application of the PPy/eRGO-modified electrode is successfully demonstrated for DA determination in human blood serum.

Controllable nanoarchitecture arrays of the transition metal selenide, supported on conductive substrates, are promising materials for high-performance electrochemical energy storage and conversion applications. Herein, Ni₃Se₂ nanowire arrays with a rich-grain-boundary are rationally grown on a nickel foam (NF) substrate by the solvothermal method. Under optimized conditions, the Ni₃Se₂ nanowire arrays prominently display high areal capacitance of 635 μA h cm⁻² at a current density of 3 mA cm⁻² and excellent rate capability. As an asymmetric supercapacitor, the Ni₃Se₂ electrode (cathode) shows a high energy density of 42.6 W h kg⁻¹ at a power density of 284.8 W kg⁻¹. When used as a two-dimensional (2D) electrode for water splitting reaction, the Ni₃Se₂ electrode exhibits high catalytic activity to achieve 100 mA cm⁻² at an overpotential of 320 mV in the oxygen evolution reaction and a low overpotential of 95 mV at a current density of 50 mA cm⁻² in the hydrogen evolution reaction in a 1.0 M KOH solution. The Ni₃Se₂ nanowire array electrode is shown to be a high-performance alkaline water electrolyzer with current density of 10 mA cm⁻² at a cell voltage of 1.62 V. The results demonstrate Ni₃Se₂ as a promising 2D highly active electrode for electrochemical energy storage and conversion applications.