On December 19, 2023, Li Bei, the research group of Changchun Institute of Optics, Precision Mechanics and Physics, Chinese Academy of Sciences, published an article entitled "Stable SERS Detection of Lactobacillus fermentum Using Optical Tweezers in a Microfluid Environment" on the Journal of Analytical Chemistry. The aim of this article is to obtain stable bacterial SERS signals in a microfluidic environment using optical tweezers, and then identify lactic acid bacteria using Raman spectroscopy.

Abstract

Rapid identification of fermented lactic acid bacteria has long been a challenge in the brewing industry. This study combined label-free surface-enhanced Raman scattering (SERS) and optical tweezer technology to construct a test platform within a microfluidic environment. Six kinds of lactic acid bacteria common in industry were tested to prove the stability of the SERS spectra. The results demonstrated that the utilization of optical tweezers to securely hold the bacteria significantly enhanced the stability of the SERS spectra. Furthermore, SVM and XGBoost machine learning algorithms were utilized to analyze the obtained Raman spectra for identification, and the identification accuracies exceeded 95% for all tested lactic acid bacteria. The findings of this study highlight the crucial role of optical tweezers in improving the stability of SERS spectra by capturing bacteria in a microfluidic environment, prove that this technology could be used in the rapid identification of lactic acid bacteria, and show great significance in expanding the applicability of the SERS technique for other bacterial testing purposes.

The paper links：

https://doi.org/10.1021/acs.analchem.3c03852