Stable SERS Detection of Lactobacillus fermentum Using Optical Tweezers in a Microfluidic Environment

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.

Raman cell sorting for single-cell research

“…(C) SERS-based flow cytometry, reproduced from Sebba et al (2009 ). (D) SERS technology combined with optical tweezers in a microfluidic environment, reproduced from Shang et al (2023 ).…”

“…The peaks of each lactic acid bacterium were significantly enhanced after SERS enhancement. This study revealed that the immobilization of bacteria using optical tweezers can significantly improve the stability of SERS spectra, expanding the practical application of SERS in bacterial detection ( Shang et al, 2023 ).…”