González-Solís Jl, Luévano-Colmenero Gh, Vargas-Mancilla J
Centro Universitario de los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco , México.
Laser Ther. 2013;22(1):37-42. doi: 10.5978/islsm.13-or-05.
Raman spectroscopy is a vibrational technique which provides information about the chemical structure. Nevertheless, since many chemicals are present in a cell at very low concentration, the Raman signal observed from a single cell is extremely weak. In surface enhanced Raman scattering (SERS), Raman signals can be enhanced by many orders of magnitude when nanoparticles are incorporated into the cell. Materials (subjects) and methods: The tumor biopsies were obtained from 5 patients who were clinically diagnosed with breast cancer. Breast cancer cells isolated from the biopsy were washed, centrifuged and seeded out. Cultivation took place in DMEM at 37°C in a humidified of 5% CO2 in air with addition of colloidal silver nanoparticles of 40 nm into the cell by sonication. Immediately, the washed cells were analyzed in phosphate buffered saline (PBS) at pH 7. Raman analysis was carried out on the Jobin-Yvon LabRAM HR800 microscope system, with a NIR 830 nm laser excitation source.
The strongly enhanced Raman signals allow Raman measurements of a single cell in the 200-1800 cm(-1) range in relatively short collection times (5 second) using 17 mW near-infrared excitation. Observed spectral features differed across the cell, but chemical constituents in the cell nucleus and cytoplasm, such as DNA, RNA, and amino acids tyrosine and phenylalanine can be identified.
Particularly strong field enhancement can be observed when nanoparticles form colloidal clusters. The results suggest that SERS could be a new technique for the identification of breast cancer cell.
拉曼光谱是一种振动技术，可提供有关化学结构的信息。然而，由于许多化学物质在细胞中的浓度非常低，从单个细胞观察到的拉曼信号极其微弱。在表面增强拉曼散射（SERS）中，当纳米颗粒掺入细胞时，拉曼信号可增强多个数量级。
材料（研究对象）与方法：从5例临床诊断为乳腺癌的患者中获取肿瘤活检组织。将从活检组织中分离出的乳腺癌细胞洗涤、离心并接种。在含有40 nm胶体银纳米颗粒的DMEM中于37°C、5%二氧化碳的湿润空气中培养，通过超声处理将纳米颗粒加入细胞中。立即在pH 7的磷酸盐缓冲盐水（PBS）中对洗涤后的细胞进行分析。在Jobin-Yvon LabRAM HR800显微镜系统上进行拉曼分析，使用近红外830 nm激光激发源。
强烈增强的拉曼信号使得在相对较短的采集时间（5秒）内，使用17 mW近红外激发，能够在200 - 1800 cm⁻¹范围内对单个细胞进行拉曼测量。观察到的光谱特征在整个细胞中有所不同，但可以识别细胞核和细胞质中的化学成分，如DNA、RNA以及氨基酸酪氨酸和苯丙氨酸。
当纳米颗粒形成胶体团簇时，可以观察到特别强的场增强。结果表明SERS可能是一种鉴定乳腺癌细胞的新技术。
