Tokyo Institute of Science Detects Nanoplastics in Water within 20 Minutes Using SPR Biosensor with PS-Binding Peptide

July 26, 2026

Science Tokyo (Institute of Science Tokyo, Japan) Japan

Overview

Researchers at the Institute of Science Tokyo have developed a rapid optical biosensor using surface plasmon resonance (SPR) for detecting 50 nm polystyrene nanoparticles (PS-NPs) in freshwater within 20 minutes. The biosensor employs a PS-binding peptide immobilized on a thin gold film via a PEG linker, achieving selective, label-free detection with a detection limit of 1.3 μg/mL. This advancement enables rapid monitoring of fine plastic pollution in the environment, contributing to the assessment of its impact on ecosystems and public health.

In Depth

Key Findings

A research team at the Institute of Science Tokyo has developed a groundbreaking optical biosensor leveraging surface plasmon resonance (SPR) technology, successfully detecting 50 nm polystyrene nanoparticles (PS-NPs) in freshwater within a mere 20 minutes. This rapid and highly sensitive detection method opens new avenues for monitoring environmental pollution by nanoplastics, addressing a growing global concern.

Technical and Clinical Details

The developed biosensor features a thin gold film surface to which specific PS-binding peptides are immobilized via a PEG linker. These peptides are designed for high affinity and selectivity towards polystyrene nanoparticles, minimizing interference from other common environmental particles. The SPR technique operates on the principle of measuring characteristic changes in the refractive index at the gold film surface, caused by the binding of molecules in its vicinity to surface plasmons. When PS-NPs bind to the peptides on the sensor surface, a distinct change in the SPR signal occurs, which is optically detected to identify the presence and concentration of nanoplastics. The system is label-free, simplifying sample preparation. With a detection limit of 1.3 μg/mL, it offers sufficient sensitivity for assessing nanoplastic concentrations in environmental water samples.

Background and Industry Context

Nanoplastic pollution has emerged as a critical environmental issue, following microplastic concerns. There are growing worries about its uptake by aquatic organisms, its progression through the food chain, and potential health risks to humans. However, due to their extremely small size, nanoplastics have been challenging to detect using conventional analytical methods. Consequently, the development of rapid and highly sensitive detection technologies has been an urgent research priority. The research from the Institute of Science Tokyo provides a promising solution to this challenge, poised to impact fields such as environmental monitoring, water treatment technologies, and public health management.

Strategic Significance and Outlook

The success of this SPR biosensor is expected to accelerate the evolution of nanoplastic detection technologies. Researchers are likely to explore its applicability to a broader range of plastic nanoparticles and diverse environmental samples (e.g., seawater, soil extracts, biological tissues). Furthermore, efforts will focus on miniaturizing the device for easier field use and integrating AI for data analysis, anticipating the establishment of real-time and wide-area monitoring networks for nanoplastic pollution. This will enable more accurate assessment of nanoplastic environmental risks and provide scientific evidence for implementing effective countermeasures, contributing to a more sustainable future.

Source: https://www.isct.ac.jp/en/news/0wb20bf07czk

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