Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell Analysis
Surface-enhanced Raman scattering (SERS) is a useful tool for label-free analysis of bacteria at the single cell level. However, low reproducibility limits the use of SERS. In this study, for the sake of sensitive and reproducible Raman spectra, we optimized the methods for preparing silver nanopart...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2020-09-01
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| Series: | Frontiers in Bioengineering and Biotechnology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fbioe.2020.573777/full |
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| author | Yingchun Yan Yingchun Yan Yong Nie Liyun An Liyun An Yue-Qin Tang Zimu Xu Xiao-Lei Wu Xiao-Lei Wu |
| author_facet | Yingchun Yan Yingchun Yan Yong Nie Liyun An Liyun An Yue-Qin Tang Zimu Xu Xiao-Lei Wu Xiao-Lei Wu |
| author_sort | Yingchun Yan |
| collection | DOAJ |
| description | Surface-enhanced Raman scattering (SERS) is a useful tool for label-free analysis of bacteria at the single cell level. However, low reproducibility limits the use of SERS. In this study, for the sake of sensitive and reproducible Raman spectra, we optimized the methods for preparing silver nanoparticles (AgNPs) and depositing AgNPs onto a cell surface. We found that fast dropwise addition of AgNO3 into the reductant produced smaller and more stable AgNPs, with an average diameter of 45 ± 4 nm. Compared with that observed after simply mixing the bacterial cells with AgNPs, the SERS signal was significantly improved after centrifugation. To optimize the SERS enhancement method, the centrifugal force, method for preparing AgNPs, concentration of AgNPs, ionic strength of the solution used to suspend the cells, and density of the cells were chosen as impact factors and optimized through orthogonal experiments. Finally, the improved method could generate sensitive and reproducible SERS spectra from single Escherichia coli cells, and the SERS signals primarily arose from the cell envelope. We further verified that this optimal method was feasible for the detection of low to 25% incorporation of 13C isotopes by the cells and the discrimination of different bacterial species. Our work provides an improved method for generating sensitive and reproducible SERS spectra. |
| first_indexed | 2024-12-14T22:26:38Z |
| format | Article |
| id | doaj.art-d1945e1d4c2b455ead08a268f7d095e3 |
| institution | Directory Open Access Journal |
| issn | 2296-4185 |
| language | English |
| last_indexed | 2024-12-14T22:26:38Z |
| publishDate | 2020-09-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Bioengineering and Biotechnology |
| spelling | doaj.art-d1945e1d4c2b455ead08a268f7d095e32022-12-21T22:45:21ZengFrontiers Media S.A.Frontiers in Bioengineering and Biotechnology2296-41852020-09-01810.3389/fbioe.2020.573777573777Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell AnalysisYingchun Yan0Yingchun Yan1Yong Nie2Liyun An3Liyun An4Yue-Qin Tang5Zimu Xu6Xiao-Lei Wu7Xiao-Lei Wu8Institute of New Energy and Low-carbon Technology, Sichuan University, Chengdu, ChinaCollege of Engineering, Peking University, Beijing, ChinaCollege of Engineering, Peking University, Beijing, ChinaInstitute of New Energy and Low-carbon Technology, Sichuan University, Chengdu, ChinaCollege of Engineering, Peking University, Beijing, ChinaInstitute of New Energy and Low-carbon Technology, Sichuan University, Chengdu, ChinaCollege of Engineering, Peking University, Beijing, ChinaCollege of Engineering, Peking University, Beijing, ChinaInstitute of Ocean Research, Peking University, Beijing, ChinaSurface-enhanced Raman scattering (SERS) is a useful tool for label-free analysis of bacteria at the single cell level. However, low reproducibility limits the use of SERS. In this study, for the sake of sensitive and reproducible Raman spectra, we optimized the methods for preparing silver nanoparticles (AgNPs) and depositing AgNPs onto a cell surface. We found that fast dropwise addition of AgNO3 into the reductant produced smaller and more stable AgNPs, with an average diameter of 45 ± 4 nm. Compared with that observed after simply mixing the bacterial cells with AgNPs, the SERS signal was significantly improved after centrifugation. To optimize the SERS enhancement method, the centrifugal force, method for preparing AgNPs, concentration of AgNPs, ionic strength of the solution used to suspend the cells, and density of the cells were chosen as impact factors and optimized through orthogonal experiments. Finally, the improved method could generate sensitive and reproducible SERS spectra from single Escherichia coli cells, and the SERS signals primarily arose from the cell envelope. We further verified that this optimal method was feasible for the detection of low to 25% incorporation of 13C isotopes by the cells and the discrimination of different bacterial species. Our work provides an improved method for generating sensitive and reproducible SERS spectra.https://www.frontiersin.org/article/10.3389/fbioe.2020.573777/fullRaman microscopySERSbacteriasingle cell analysisbacteria detection |
| spellingShingle | Yingchun Yan Yingchun Yan Yong Nie Liyun An Liyun An Yue-Qin Tang Zimu Xu Xiao-Lei Wu Xiao-Lei Wu Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell Analysis Frontiers in Bioengineering and Biotechnology Raman microscopy SERS bacteria single cell analysis bacteria detection |
| title | Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell Analysis |
| title_full | Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell Analysis |
| title_fullStr | Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell Analysis |
| title_full_unstemmed | Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell Analysis |
| title_short | Improvement of Surface-Enhanced Raman Scattering Method for Single Bacterial Cell Analysis |
| title_sort | improvement of surface enhanced raman scattering method for single bacterial cell analysis |
| topic | Raman microscopy SERS bacteria single cell analysis bacteria detection |
| url | https://www.frontiersin.org/article/10.3389/fbioe.2020.573777/full |
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