SERS-Based Quantification of Biomarker Expression at the Single Cell Level Enabled by Gold Nanostars and Truncated Aptamers,Bioconjugate Chemistry

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SERS-Based Quantification of Biomarker Expression at the Single Cell Level Enabled by Gold Nanostars and Truncated Aptamers
Bioconjugate Chemistry ( IF 4.0 ) Pub Date : 2018-08-15 00:00:00 , DOI: 10.1021/acs.bioconjchem.8b00397
Manjari Bhamidipati ₁ , Hyeon-Yeol Cho ₂ , Ki-Bum Lee _{2,

3} , Laura Fabris ₄

Affiliation

Surface-enhanced Raman spectroscopy (SERS)-based biosensors have been used increasingly over the past few years for cancer detection and diagnosis. SERS-based imaging offers excellent sensitivity and has advantages over other detection techniques such as fluorescence. In this study, we developed a novel biosensor to detect the cancer biomarker epithelial cell adhesion molecule (EpCAM) and quantify its expression at the single cell level. EpCAM is one of the most commonly expressed markers on a variety of cancer cells; importantly it has been suggested that reduction of its expression levels could be associated with the epithelial to mesenchymal transition (EMT) and thus to the onset of metastasis. Therefore, monitoring variations in expression levels of this membrane biomarker would improve our ability to monitor cancer progression. The described substrate-based biosensor was developed employing gold nanostars functionalized with EpCAM aptamer molecules and was able to quantify subnanomolar concentrations of EpCAM protein in solution. Importantly, we demonstrated its use to quantify EpCAM expression on the surface of two cancer cells, MCF-7 and PC-3. We also compared the binding efficiency of two EpCAM DNA aptamers of different lengths and observed a substantial improvement in the sensitivity of detection by employing the shorter aptamer sequence, probably due to the reduced number of conformations possible at room temperature with the truncated oligonucleotide. Detailed characterization of the substrates was carried out using both SERS maps and atomic force microscopy. These substrate-based diagnostic devices promise to be relevant for monitoring phenotype evolutions in cancer cells, blood, and other bodily fluids, thus improving our ability to follow in real time disease onset and progression.

中文翻译：

基于SERS的金纳米星和截断的适体在单细胞水平上对生物标志物表达的定量

在过去的几年中，基于表面增强拉曼光谱（SERS）的生物传感器已越来越多地用于癌症的检测和诊断。基于SERS的成像具有出色的灵敏度，并且比其他检测技术（例如荧光）具有优势。在这项研究中，我们开发了一种新型的生物传感器来检测癌症生物标志物上皮细胞粘附分子（EpCAM）并定量其在单细胞水平上的表达。EpCAM是多种癌细胞上最普遍表达的标志物之一。重要的是，已经表明其表达水平的降低可能与上皮向间充质转化（EMT）有关，并因此与转移的发生有关。因此，监测这种膜生物标志物表达水平的变化将提高我们监测癌症进展的能力。所描述的基于底物的生物传感器是利用用EpCAM适体分子功能化的金纳米星开发的，能够量化溶液中EpCAM蛋白的亚纳摩尔浓度。重要的是，我们证明了其可用于量化两种癌细胞MCF-7和PC-3表面上EpCAM的表达。我们还比较了两种不同长度的EpCAM DNA适体的结合效率，并观察到采用较短的适体序列可显着提高检测灵敏度，这可能是由于在室温下截短的寡核苷酸可能减少了构象数目。使用SERS图和原子力显微镜对底物进行详细的表征。

更新日期：2018-08-15

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