Potential for Nile red dye-based analysis of microplastics from oceanic samples

The Global production of plastics has exceeded over 300 million metric tons. Billions of tons of plastic waste that is generated gets accumulated as plastic debris in soil, sediments, oceans and surface water with no obvious strategy to tackle them. The plastics disposed in the water and land ultimately disintegrate to microplastics, widely accepted as particles <; 5 mm size. These microplastics are ubiquitous contaminants prevalent in the environment and pose great ecological hazard. Ensuring sustainability of coastal marine areas worldwide and reducing biodiversity loss has long been identified as a global challenge. However, dearth of scientific strategies and standardized protocols for fast and accurate detection of microplastics is a matter of concern and needs immediate attention. Therefore, robust, reliable and high through-put detection method for microplastics in oceanic environment is highly sought after. Quite a few studies have explored the potential of Nile red a solvatochromic dye in detection of microplastics. However, often Nile red alone cannot be used in quantifying microplastic due to false positives generated by staining of organic matter. In this work, we have adopted a method based on costaining of microplastics using Nile red dye and Methylene blue by fluorescence microscopy. We have observed that Nile red overestimated microplastic particles and this study serves as foundation to our future work.