Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China.
Anal Bioanal Chem. 2022 Jul;414(17):4977-4985. doi: 10.1007/s00216-022-04125-0. Epub 2022 May 23.
Phenotyping of bacteria with vibrational spectroscopy has caught much attention in bacteria-related research. It is known that many factors could affect this process. Among them, solution pH maintenance is crucial, yet its impact on the bacterial SERS spectra is surprisingly neglected. In this work, we focused on two situations related to pH maintenance: the effect of the same buffer on the SERS spectra of bacteria under different pH values, and the influence of different buffers on the SERS spectra of bacteria under the same pH value. Specifically, Britton-Robison (BR) buffer was used to evaluate the effect of pH value on bacteria SERS spectra thanks to its wide pH range. Four different buffers, namely BR buffer, acetate buffer, phosphate buffer, and carbonate buffer, were used to illustrate the impact of buffer types on SERS spectra of bacteria. The results showed that the intensity and number of characteristic peaks of the SERS spectra of Gram-negative (G -) bacteria changed more significantly than Gram-positive (G +) bacteria with the change of pH value. Furthermore, compared with phosphate buffer and carbonate buffer, BR buffer could bring more characteristic SERS bands with better reproducibility, but slightly inferior to acetate buffer. In conclusion, the influence of the pH and types of the buffer on the SERS spectra of bacteria are worthy of further discussion.
利用振动光谱对细菌进行表型分析在与细菌相关的研究中受到了广泛关注。已知有许多因素会影响这个过程。其中，维持溶液 pH 值至关重要，但令人惊讶的是，其对细菌 SERS 光谱的影响却被忽视了。在这项工作中，我们专注于与 pH 值维持相关的两种情况：同一种缓冲液对不同 pH 值下细菌 SERS 光谱的影响，以及不同缓冲液对同一 pH 值下细菌 SERS 光谱的影响。具体来说，我们使用 Britton-Robison（BR）缓冲液来评估 pH 值对细菌 SERS 光谱的影响，因为它的 pH 值范围很广。我们使用了四种不同的缓冲液，即 BR 缓冲液、乙酸盐缓冲液、磷酸盐缓冲液和碳酸盐缓冲液，来说明缓冲液类型对细菌 SERS 光谱的影响。结果表明，随着 pH 值的变化，革兰氏阴性（G−）细菌的 SERS 光谱的强度和特征峰数量变化更为显著，而革兰氏阳性（G+）细菌则变化较小。此外，与磷酸盐缓冲液和碳酸盐缓冲液相比，BR 缓冲液可以带来更多具有更好重现性的特征 SERS 带，但稍逊于乙酸盐缓冲液。总之，缓冲液的 pH 值和类型对细菌 SERS 光谱的影响值得进一步讨论。
