Effect of micro/nano-plastics on environment and recent advances in their detection strategies

Plastic pollution has become the most pressing environmental challenge of twenty-first century due to extensive accumulation and long-term persistence of plastics across various ecosystems. The major threat associated with plastic waste is their progressive fragmentation into smaller-sized micro- and nano-plastics (MNPs), through physical, chemical and biological degradation processes. Owing to their small size, high surface-area-to-volume ratio and hydrophobicity, MNPs adsorb and transport a wide range of environmental contaminants, and interact with living systems at molecular and cellular levels, thereby posing a severe risk to the ecosystem. Despite their negative implications, the accurate detection and monitoring of MNPs remain a challenge. Conventional detection strategies are expensive, require sophisticated equipment and skilled personnel, and are not suitable for rapid on-site detection. These limitations underscore the urgent need for innovative detection strategies that offer high sensitivity, selectivity, and real-time analytical capabilities. In this context, the present review provides a systematic and comprehensive overview of sources, formation pathways and toxicological impacts of MNP in various systems. Furthermore, conventional methods for MNPs detection are critically evaluated highlighting their advantages and inherent limitations. Particular emphasis is given on biosensors, with a focus on aptamer-based platforms as promising tool for rapid, sensitive, and selective detection of MNPs. By systematically evaluating the MNP detection strategies, this review identifies key knowledge gaps, discusses challenges limiting the development and large scale applications of aptamer-based detection methods and outline the future research directions. Overall, this review provides valuable insights for researchers and policymakers to address the global challenge of MNPs pollution.