Role of nano-enabled sensors in contaminant detection and management: a review

The growing concern over environmental contamination, coupled with advancements in the digital age, has underscored the urgent need for innovative, accurate, and accessible monitoring systems. Nano-enabled sensors have emerged as transformative tools for detecting environmental pollutants with enhanced sensitivity and specificity. This review paper investigates the evolution, design, and application of nanosensors, emphasising their role in monitoring critical contaminants like toxic gases, pathogens, pesticides, and heavy metals. Nano-enabled gas sensors, characterised by their ambient-temperature operation, relatively lower cost, and flexibility are highlighted as cutting-edge technologies for point-of-care and point-of-location testing. Similarly, the detection of heavy metals like arsenic, whose contamination poses severe health risks worldwide, has been revolutionised by nano-enabled methods. Advances in the fabrication of nanostructures and the modulation of nanomaterial chemistry have remarkably increased the sensitivity, selectivity, and efficiency of these sensors. By bridging the gap between data collection and actionable insights, nano-enabled sensors hold the potential to transform environmental monitoring, providing a systematic and quantitative understanding of pollutants. This review critically compares nanomaterial classes, signal transduction strategies, and readiness for deployment and has identified the key challenges in scalability, long-term stability, and filling the gaps between innovation in the laboratory and implementation in the environment.