Accurate identification of living Bacillus spores using laser tweezers Raman spectroscopy and deep learning

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2023-03, Vol.289, p.122216, Article 122216
• Main Authors: Du, Fusheng, He, Lin, Lu, Xiaoxu, Li, Yong-qing, Yuan, Yufeng
• Format: Article
• Language: English
• Subjects: Bacillus spore classification; Deep learning; Laser tweezers Raman spectroscopy; Metabolic phase identification; Single cell level
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2022.122216

[Display omitted] •Accurately, rapidly, and noninvasively identifying living Bacillus spores was performed using LTRS and convolutional neural network (CNN) at a single cell level.•The most classification contribution based on CNN model were further extracted.•The possibility to characterize sporulation process at different growth phases was studied by LTRS and CNN. Accurately, rapidly, and noninvasively identifying Bacillus spores can greatly contribute to controlling a plenty of infectious diseases. Laser tweezers Raman spectroscopy (LTRS) has confirmed to be a powerful tool for studying Bacillus spores at a single cell level. In this study, we constructed a single-cell Raman spectra dataset of living Bacillus spores and utilized deep learning approach to accurately, nondestructively identify Bacillus spores. The trained convolutional neural network (CNN) could efficiently extract tiny Raman spectra features of five spore species, and provide a prediction accuracy of specie identification as high as 100 %. Moreover, the spectral feature differences in three Raman bands at 660, 826, and 1017 cm−1 were confirmed to mostly contribute to producing such high prediction accuracy. In addition, optimal CNN model was employed to monitor and identify sporulation process at different metabolic phases in one growth cycle. The obtained average prediction accuracy of metabolic phase identification was approximately 88 %. It can be foreseen that, LTRS combined with CNN approach have great potential for accurately identifying spore species and metabolic phases at a single cell level, and can be gradually extended to perform identification for many unculturable bacteria growing in soil, water, and food.