目的

探讨以纳米银溶胶为增强基底的变异链球菌（Streptococcus mutans）表面增强拉曼光谱（SERS）。

方法

葡萄糖还原硝酸银制备纳米银溶胶，以该溶胶为增强基底，用DXR 激光显微拉曼光谱仪获取变异链球菌的SERS。

结果

纳米银溶胶粒子为分散性好、均粒径约为11.08 nm的球形颗粒，其增强效果较高；变异链球菌SERS 的拉曼信号强且峰较多，被增强的谱峰主要集中在细胞壁成分相关的700 ～1800 cm^-1 区域，在721.94、1270.35、1371.83、1441.51、1569.22、1628.91、2922.65 cm^-1 处均有明显的拉曼振动峰。

结论

以葡萄糖还原硝酸银制备的纳米银溶胶为基底，可获得变异链球菌SERS，可用于变异链球菌的检测及其细胞壁成分的分析等，有助于进一步探索变异链球菌的致龋机制及研制新型防龋药物。

Objective

To investigate the surface-enhanced Raman spectroscopy （SERS） of Streptococcus mutans （S.mutans） with active silver colloid nanoparticles as the substrate.

Methods

Silver colloids were produced for SERS experiments by reduction of silver nitrate with glucose. SERS of S.mutans were collected using a DXR laser micro Raman spectrometer.

Results

The silver nanoparticles were spherical with 11.08 nm mean size which had better dispersibility and higher enhanced effect. The SERS of S.mutans had higher Raman signal intensity and more Raman peaks. The bands enhanced spectral peaks in the 700 cm^-1 ～1800 cm^-1 region were assigned to bacterial cell wall， according to the obtained SERS of S.mutans. In particular， at 721.94， 1270.35， 1371.83， 1441.51， 1569.22， 1628.91，2922.65 cm^-1 regions had significant Raman peaks.

Conclusions

We can get SERS of S.mutans with silver colloid nanoparticles as active substrate which was prepared by reduction of silver nitrate with glucose as reducing agent. With SERS， we can detect S.mutans and analysis the composition of its cell wall. Hence， it has a great potential for further exploration the cariogenic mechanism of S.mutans， and to develop new methods to anti-caries in future study.