CdSe/CdS core shelled quantum dots (QDs) were prepared by colloidal synthesis using a binary ligand system and a non-coordinating, reusable solvent n-octadecane (nOD). Both the synthesis of CdSe and CdSe/CdS core shelled quantum dots were achieved by hot injection technique at much lower temperatures than reported earlier. The use of binary ligand facilitated enough nucleation and growth. Red shift in absorption spectra, an enhanced crystallite and particle size is evidenced by XRD and TEM respectively, confirming the formation of core shell structure of CdSe/CdS. The synthesized core shells exhibited high fluorescence intensity, long term stability and good mono dispersion, making it a potential material for bio-imaging and sensing. Core shell QDs were modified with mercapto propionic acid (MPA) to impart aqueous solubility. Studies on cytotoxicity of shelled QDs reveal good bio compatibility with a very minimum toxicity of IC50 = 20 μg/L. These QDs were used for sensing E. coli. Ordinary glass slide, modified using plasma etching is surface modified through APTES aiding conjugation of antibodies. Anti- E. coli polyclonal antibody on glass matrix (slide) and antibody conjugated QDs were used for detection of E. coli in a typical sandwich model. The excellent optical transparency of glass and high emission of QDs lead to detection of E.coli with a limit of detection of 50 CFU/mL.

中文翻译：

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表面修饰的玻璃基板，使用高度稳定且发光的CdSe / CdS核壳量子点来传感大肠杆菌。

CdSe / CdS核壳量子点（QDs）是使用二元配体系统和非配位，可重复使用的溶剂正十八烷（nOD）通过胶体合成制备的。CdSe和CdSe / CdS核壳量子点的合成均通过热注入技术在比以前报道的温度低得多的温度下完成。二元配体的使用促进了足够的成核和生长。XRD和TEM分别证明了吸收光谱的红移，微晶和粒径的增加，证实了CdSe / CdS核壳结构的形成。合成的核壳表现出高荧光强度，长期稳定性和良好的单分散性，使其成为生物成像和传感的潜在材料。用巯基丙酸（MPA）修饰核壳QD，以赋予水溶性。对带壳QDs的细胞毒性研究表明，它具有良好的生物相容性，其最小毒性IC50 = 20μg/ L。这些QD用于感应大肠杆菌。通过等离子蚀刻改性的普通载玻片通过APTES进行表面改性以帮助抗体结合。在典型的三明治模型中，玻璃基质（载玻片）上的抗大肠杆菌多克隆抗体和结合抗体的QD用于检测大肠杆菌。玻璃出色的光学透明性和QD的高发射导致检测到大肠杆菌，检测限为50 CFU / mL。玻璃基质（载玻片）上的大肠杆菌多克隆抗体和结合抗体的QD用于检测典型三明治模型中的大肠杆菌。玻璃极好的光学透明性和QD的高发射导致检测到大肠杆菌，检测限为50 CFU / mL。玻璃基质（载玻片）上的大肠杆菌多克隆抗体和结合抗体的QD用于检测典型三明治模型中的大肠杆菌。玻璃出色的光学透明性和QD的高发射导致检测到大肠杆菌，检测限为50 CFU / mL。