# Long-Term Stable Biosensing Using Multiscale Biostructure-Preserving Metal Thin Films

## TL;DR

This paper introduces a new biosensing method using metal thin films to detect microorganisms with high sensitivity and long-term stability.

## Contribution

A novel fabrication method using metal thin films to preserve biostructures and improve biosensor durability and sensitivity.

## Key findings

- Metal thin films enabled detection of Norovirus-like particles at 10 fg/mL sensitivity.
- The biosensors retained reactivity after repeated use and storage at room temperature.
- The method allows rapid detection within less than a minute.

## Abstract

Microparticle detection technology uses materials that can specifically recognize complex biostructures, such as antibodies and aptamers, as trapping agents. The development of antibody production technology and simplification of sensing signal output methods have facilitated commercialization of disposable biosensors, making rapid diagnosis possible. Although this contributed to the early resolution of pandemics, traditional biosensors face issues with sensitivity, durability, and rapid response times. We aimed to fabricate microspaces using metallic materials to further enhance durability of mold fabrication technologies, such as molecular imprinting. Low-damage metal deposition was performed on target protozoa and Norovirus-like particles (NoV-LPs) to produce thin metallic films that adhere to the material. The procedure for fitting the object into the bio structured space formed on the thin metal film took less than a minute, and sensitivity was 10 fg/mL for NoV-LPs. Furthermore, because it was a metal film, no decrease in reactivity was observed even when the same substrate was stored at room temperature and reused repeatedly after fabrication. These findings underscore the potential of integrating stable metallic structures with bio-recognition elements to significantly enhance robustness and reliability of environmental monitoring. This contributes to public health strategies aimed at early detection and containment of infectious diseases.