Elakkiya Venugopal, Menon Mridula Prakash, Nataraj Devaraj, Biji Pullithadathil, Selvakumar Rajendran
Nanobiotechnology Laboratory, PSG Institute of Advanced Studies, Peelamedu, Coimbatore 641004, India.
Department of Physics, Bharathiar University, Coimbatore 641046, India.
IET Nanobiotechnol. 2017 Apr;11(3):268-276. doi: 10.1049/iet-nbt.2016.0012.
The present study focus on optical sensing of breast cancer antigen 15.3 (CA 15.3) using cadmium sulphide quantum dot (CdS-QD) in saline and serum samples spiked with antigen. The surface of CdS-QD was modified by cysteamine capping followed by tagging of CA 15.3 antibody. The samples were characterised using UV-visible absorption spectroscopy (UV-VIS Spectroscopy), Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM) attached with energy-dispersive X-ray spectroscopy, phase contrast inverted epi-fluorescence microscopy and photoluminescence (PL) spectrophotometry (EDS). The CdS-QD showed a mean diameter of 3.02 ± 0.6nm. The complex formed after antigen-antibody interaction resulted in distinguishable optical and fluorescence intensity with respect to varying concentration of antigen. The PL study revealed that CA 15.3 antibody labelled CdS QD can detect CA 15.3 tumour marker even at very low concentration of 0.002 KU/L with a constant response time of 15min. This study clearly indicates that detection of CA 15.3 at low concentration is possible using surface modified CdS QD in serum samples and can find immense applications in biosensor development for detection of breast cancer marker similar to various automated detection kits available in market.
本研究聚焦于在添加了抗原的生理盐水和血清样本中，使用硫化镉量子点（CdS-QD）对乳腺癌抗原15.3（CA 15.3）进行光学传感。CdS-QD的表面先用半胱胺封端进行修饰，然后标记CA 15.3抗体。使用紫外可见吸收光谱（UV-VIS光谱）、傅里叶变换红外光谱（FTIR）、配备能量色散X射线光谱的高分辨率透射电子显微镜（HRTEM）、相差倒置落射荧光显微镜和光致发光（PL）分光光度法（EDS）对样本进行表征。CdS-QD的平均直径为3.02±0.6nm。抗原-抗体相互作用后形成的复合物，相对于不同浓度的抗原，产生了可区分的光学和荧光强度。PL研究表明，即使在0.002 KU/L的极低浓度下，CA 15.3抗体标记的CdS QD也能检测到CA 15.3肿瘤标志物，恒定响应时间为15分钟。这项研究清楚地表明，使用血清样本中表面修饰的CdS QD可以检测低浓度的CA 15.3，并且在类似于市场上各种自动检测试剂盒的乳腺癌标志物检测生物传感器开发中具有巨大的应用潜力。
