Characterization and application of quantum dot nanocrystal¨Cmonoclonal antibody conjugates for the determination of sulfamethazine in milk by fluoroimmunoassay

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• 作者：Jianzhong Shen ; Fei Xu ; Haiyang Jiang ; Zhanhui Wang ; Jing Tong ; Pengju Guo and Shuangyang Ding
• 关键词：Quantum dots ; Monoclonal antibody ; Sulfamethazine ; Milk residue
• 刊名：Analytical and Bioanalytical Chemistry
• 出版年：2007
• 出版时间：December, 2007
• 年：2007
• 卷：389
• 期：7-8
• 页码：2243-2250
• 全文大小：199.2 KB

文摘

Quantum dot (Qdot) nanocrystals have been increasingly used as fluorescence labels in fluoroimmunoassays recently because of their excellent optical characteristics. In this paper, a new monoclonal antibody (MAb) against sulfamethazine (SMZ) was successfully produced and linked to Qdot nanocrystals by covalent coupling. The Qdot–MAb conjugates were characterized by SDS-PAGE and high-performance capillary electrophoresis (HPCE). An enzyme-linked immunosorbent assay (ELISA) method was utilized to evaluate the antigen–antibody binding affinity and then a novel direct competitive fluorescence-linked immunosorbent assay (cFLISA) for the detection of SMZ in milk by using Qdots as fluorescent labels was evaluated. The results showed that the 50 % inhibition values (IC₅₀) of the cFLISA were 4.3 ng/mL in milk and 5.2 ng/mL in PBS, and the limits of detection (LODs) were 0.6 ng/mL in milk and 0.4 ng/mL in PBS, respectively. The recoveries of SMZ from spiked milk samples at levels of 10–100 ng/mL ranged from 94 to 106 % , with coefficients of variation (CVs) of 2.1–9.2 % .