Aswathy J, Jahnavi S, Krishna R, Manzoor K, Nair Shantikumar, Menon Deepthy
Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwavidyapeetham, Kochi 682041, Kerala, India.
J Nanosci Nanotechnol. 2011 Sep;11(9):7611-20. doi: 10.1166/jnn.2011.4726.
The present study details the development of biotin tagged avidin functionalized Zinc Sulphide [ZnS] nanocrystals through a simple aqueous chemistry route at room temperature for targeted imaging applications. Surface functionalization of Manganese doped ZnS nanocrystals with L-cysteine provided functional groups that facilitated its conjugation to avidin. Further biotinylation of these particles through the strong non-covalent interaction between biotin and avidin enabled highly specific labeling of the biotin receptors on human hepatocellular carcinoma (HepG2) cells. The nanobioconjugates thus developed exhibited stable and brilliant fluorescence upon labeling the biotin receptors on cells as observed through fluorescence microscopy. Characterization studies using X-ray diffraction, dynamic light scattering as well as Fourier transform infrared spectroscopy revealed the bioconjugated particles to be appropriately functionalized and stable, with size ranging from 50 to 80 nm. Cytotoxicity of this material system evaluated using MTT, LDH leakage and apoptosis assay revealed its non-toxic nature even for high concentrations extending upto 250 microM and 48 hours of incubation. Our results confirmed that biotinylated ZnS nanocrystals offer great potential for highly specific labeling and targeted imaging of cancer cells.
本研究详细阐述了通过在室温下采用简单的水相化学路线，开发用于靶向成像应用的生物素标记抗生物素蛋白功能化硫化锌[ZnS]纳米晶体。用L-半胱氨酸对锰掺杂的ZnS纳米晶体进行表面功能化，提供了有助于其与抗生物素蛋白共轭的官能团。通过生物素与抗生物素蛋白之间强烈的非共价相互作用对这些颗粒进行进一步生物素化，能够对人肝癌（HepG2）细胞上的生物素受体进行高度特异性标记。通过荧光显微镜观察，如此开发的纳米生物共轭物在标记细胞上的生物素受体时表现出稳定而明亮的荧光。使用X射线衍射、动态光散射以及傅里叶变换红外光谱进行的表征研究表明，生物共轭颗粒功能化适当且稳定，尺寸范围为50至80纳米。使用MTT、LDH泄漏和凋亡测定法评估该材料系统的细胞毒性，结果表明即使在高达250 microM的高浓度和长达48小时的孵育条件下，其仍具有无毒性质。我们的结果证实，生物素化的ZnS纳米晶体在癌细胞的高度特异性标记和靶向成像方面具有巨大潜力。
