# Recent Advancements in the SERS-Based Detection of E. coli

## TL;DR

This paper reviews recent progress in using SERS for detecting E. coli, focusing on substrate design and integration with biosensing systems for real-time detection.

## Contribution

A critical evaluation of SERS substrate design and integration strategies for improving E. coli detection in field applications.

## Key findings

- SERS substrates made of gold, silver, copper, and aluminum are commonly used for E. coli detection.
- Integrated lab-on-chip platforms and portable Raman devices are being developed to improve field applicability.
- Current limitations include reproducibility and stability, which future research aims to address.

## Abstract

Overview of SERS for E. coli detection, including historical development, fundamental principles, and key factors influencing sensitivity, specificity, and reproducibility.

Critical evaluation of SERS substrate design, covering fabrication strategies, nanoparticle materials, shapes, sizes, and excitation wavelength, and their impact on E. coli detection performance.

Comprehensive survey of recent advances in SERS-based E. coli detection, providing a consolidated resource to help researchers select appropriate detection strategies for different applications.

In-depth analysis of advanced and integrated SERS approaches for E. coli detection, highlighting current limitations and identifying research gaps to guide future developments.

Escherichia coli (E. coli) is a well-established indicator of faecal pollution and a potent pathogen linked to numerous gastrointestinal and systemic illnesses. Ensuring public safety requires rapid and sensitive detection methods capable of real-time, on-site deployment. Many conventional techniques are either laborious, time-intensive, costly, or require complex infrastructure, limiting their applicability in field settings. Raman spectroscopy offers label-free molecular fingerprinting; however, its inherently weak scattering signals restrict its effectiveness as a standalone technique. Surface-Enhanced Raman Spectroscopy (SERS) overcomes this limitation by exploiting plasmonic enhancement from nanostructured metallic substrates—most commonly gold, silver, copper, and aluminium. Despite the commercial availability of SERS-active substrates, challenges remain in achieving high reproducibility, long-term stability, and true field applicability, necessitating the development of integrated lab-on-chip platforms and portable, handheld Raman devices. This review critically examines recent advances in SERS-based E. coli detection across water and perishable food products with particular emphasis on the evolution of SERS substrate design, the incorporation of biosensing elements, and the integration of electrochemical and microfluidic systems. By contrasting conventional SERS approaches with next-generation biosensing strategies, this paper outlines pathways toward robust, real-time pathogen detection technologies suitable for both laboratory and field applications.