State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China.
Anal Chem. 2013 Jul 2;85(13):6505-10. doi: 10.1021/ac401105p. Epub 2013 Jun 14.
A modular labeling strategy was presented for electrochemical immunoassay via supramolecular host-guest interaction between β-cyclodextrin (β-CD) and adamantine (ADA). An ADA-labeled antibody (ADA-Ab) was synthesized via amidation, and the number of ADA moieties loaded on a single antibody was calculated to be ~7. The β-CD-functionalized gold-palladium bimetallic nanoparticles (AuPd-CD) were synthesized in aqueous solution via metal-S chemistry and characterized with transmission electron microscopy and X-ray photoelectron spectra. After the ADA-Ab was bound to the antigen-modified electrode surface with a competitive immunoreaction, AuPd-CD as a signal tag was immobilized onto the immunosensor by a host-guest interaction, leading to a large loading of AuPd nanoparticles. The highly efficient electrocatalysis by AuPd nanoparticles for NaBH4 oxidation produced an ultrasensitive response to chloramphenicol as a model of a small molecule antigen. The immunoassay method showed a wide linear range from 50 pg/mL to 50 μg/mL and a detection limit of 4.6 pg/mL. The specific recognition of antigen by antibody resulted in good selectivity for the proposed method. The host-guest interaction strategy provided a universal labeling approach for the ultrasensitive detection of small molecule targets.
一种基于超分子主客体相互作用的电化学免疫分析模块化标记策略被提出。通过酰胺化反应合成了金刚烷（ADA）标记的抗体（ADA-Ab），并计算出每个抗体上负载的 ADA 数量约为 7。通过金属-S 化学在水溶液中合成了β-环糊精（β-CD）功能化的金钯双金属纳米粒子（AuPd-CD），并通过透射电子显微镜和 X 射线光电子能谱对其进行了表征。在抗原修饰电极表面通过竞争性免疫反应结合 ADA-Ab 后，作为信号标签的 AuPd-CD 通过主客体相互作用固定在免疫传感器上，导致 AuPd 纳米粒子的高负载量。AuPd 纳米粒子对硼氢化钠氧化的高效电催化作用对氯霉素（一种小分子抗原的模型）产生了超灵敏的响应。免疫分析方法的线性范围从 50pg/mL 到 50μg/mL，检测限为 4.6pg/mL。抗体对抗原的特异性识别导致该方法具有良好的选择性。主体客体相互作用策略为小分子目标物的超灵敏检测提供了一种通用的标记方法。
