Selection of Plastic-Binding DNA Aptamers for Microplastics Detection

Abstract

Plastics are critical materials for modern technological applications, yet environmental contamination by microplastics has become a growing concern. In this study, DNA aptamers were isolated for two of the most abundant plastic materials: polyvinylchloride (PVC) and polystyrene (PS). These aptamers contain approximately 90 % cytosine and thymine but only 10 % purine content. Among them, the PVC-1 aptamer binds to PVC with a six-fold higher capacity than a random sequenced DNA. Among the tested plastic materials, PVC and PS exhibited the highest specific binding capacity. Using fluorophore-labeled PVC-1 aptamer, PS/PVC microplastics as low as 1 mg were detected, and the aptamer was selective for microplastics over other environmentally relevant materials, such as silica. Molecular dynamics simulations indicated that the aptamer attempted to maximize contact with the plastic surface for adsorption. This plastic-binding aptamer is expected to find applications in environmental monitoring and has fundamental implications for surface-binding aptamers.