Department of Analytical Chemistry, University of Córdoba, E-14071 Córdoba, Spain.
Biosens Bioelectron. 2011 Jul 15;26(11):4368-74. doi: 10.1016/j.bios.2011.04.050. Epub 2011 May 6.
Intensely fluorescent, colistin-functionalised CdSe/ZnS QDs (Colis-QDs) nanoparticles, are synthesized and used as sensitive probes for the detection of Escherichia coli, a Gram-negative bacteria. Colistin molecules are attached to the terminal carboxyl of the mercaptoacetic acid-capped QDs in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) as amide bond promoters. The TEM analysis of bacteria treated with Colis-QDs conjugates showed the accumulation of Colis-QDs in the cell wall of E. coli. Under the recommended working conditions, the method provides a detection limit as few as 28 E. coli cells per mL, which is competitive which more elaborate detection systems. The simplicity of the method together with short analysis time (< 15 min, without including preparation and photoactivation of the Colis-QDs conjugate) make the proposed approach useful as quick bacteria screening system.
强烈荧光的、黏菌素功能化的 CdSe/ZnS QDs（Colis-QDs）纳米粒子被合成，并用作检测革兰氏阴性细菌大肠杆菌的敏感探针。在 1-乙基-3-(3-二甲基氨基丙基）碳二亚胺盐酸盐（EDC）和 N-羟基琥珀酰亚胺（NHS）作为酰胺键促进剂的存在下，黏菌素分子附着在巯基乙酸封端的 QDs 的末端羧基上。用 Colis-QDs 缀合物处理的细菌的 TEM 分析表明，Colis-QDs 在大肠杆菌细胞壁中积累。在推荐的工作条件下，该方法的检测限低至每毫升 28 个大肠杆菌细胞，与更复杂的检测系统相当。该方法的简单性以及短的分析时间（<15 分钟，不包括 Colis-QDs 缀合物的制备和光活化）使得所提出的方法可作为快速细菌筛选系统有用。
