Advances and opportunities in point-of-care detection of toxic metals: a review of electrochemical and non-electrochemical approaches

Heavy metal contamination remains a persistent global threat to human health and the environment, driving the urgent need for rapid, portable, and sensitive detection technologies. Recent advances in point-of-care (POC) platforms have enabled real-time monitoring of toxic metals in diverse matrices, including soil, water, food, and biological fluids. Electrochemical approaches, particularly screen-printed electrode systems, have emerged as highly adaptable tools. These systems achieve ultralow detection limits through nanomaterial modifications and enable multiplexed detection using techniques such as square-wave anodic stripping voltammetry and differential pulse voltammetry. Complementary paper-based analytical devices provide low-cost, disposable, and environmentally friendly sensing formats. These platforms integrate electrochemical, fluorescent, and colorimetric strategies, often coupled with smartphone-based readouts for real-time field deployment. Smartphone-integrated systems further enhance accessibility by combining miniaturized sensing with wireless connectivity, cloud-based data sharing, and machine learning algorithms that improve signal analysis and enable predictive monitoring. Portable optical spectroscopy kits extend sensitivity to trace metals in clinical, environmental, and food matrices, while wearable sensors, including textiles, wristbands, patches, and gloves, allow for noninvasive, continuous assessment of biofluids and environmental exposures. Importantly, emerging ultrafast electrochemical techniques, such as fast-scan cyclic voltammetry at carbon fiber microelectrodes, hold the potential to detect metal speciation with unprecedented temporal resolution. When coupled with artificial intelligence (AI), these approaches can deconvolute overlapping signals, enhance selectivity, and provide actionable insights into exposure dynamics. Collectively, these POC platforms represent a trajectory toward miniaturized, intelligent, and multiplexed sensing systems, offering scalable, real-world solutions for environmental monitoring, occupational safety, and personalized healthcare. The integration of advanced electrochemical methods, wearable technologies, and AI-driven analytics highlights the transformative potential of next-generation POC devices for comprehensive heavy metal surveillance.