Zacco E, Galve R, Marco M P, Alegret S, Pividori M I
Grup de Sensors i Biosensors, Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain.
Biosens Bioelectron. 2007 Mar 15;22(8):1707-15. doi: 10.1016/j.bios.2006.07.037. Epub 2006 Nov 7.
A novel and very sensitive electrochemical immunosensing strategy for the detection of atrazine based on affinity biocomposite transducers is presented. Firstly, the graphite-epoxy composite transducer was bulk-modified with different universal affinity biomolecules, such as avidin and Protein A. Two strategies for the immobilization of the anti-atrazine antibodies on both biocomposite transducers were evaluated: 'wet-affinity' and 'dry-assisted affinity' immobilization. Finally, the performance of a novel anti-atrazine immunocomposite bulk-modified with anti-atrazine antibodies was also evaluated. The better immobilization performance of the anti-atrazine antibodies was achieved by 'dry-assisted affinity' immobilization on Protein A (2%) graphite-epoxy biocomposite (ProtA(2%)-GEB) as a transducer. The immunological reaction for the detection of atrazine performed on the ProtA(2%)-GEB biosensors is based on a direct competitive assay using atrazine-HRP tracer as the enzymatic label. The electrochemical detection is thus achieved through a suitable substrate and a mediator for the enzyme HRP. This novel strategy was successfully evaluated using spiked orange juice samples. The detection limit for atrazine in orange juices using the competitive electrochemical immunosensing assay was found to be 6 x 10(-3) microgL-1 (0.03 nmolL-1) thus this biosensing method accomplishes by far the LODs required for the European Community directives for potable water and food samples (0.1 microgL-1). This strategy offers great promise for rapid, simple, cost effective, and on-site biosensing of biological, food, and environmental samples.
提出了一种基于亲和生物复合传感器检测阿特拉津的新型且非常灵敏的电化学免疫传感策略。首先，用不同的通用亲和生物分子（如抗生物素蛋白和蛋白A）对石墨 - 环氧复合传感器进行本体修饰。评估了两种将抗阿特拉津抗体固定在两种生物复合传感器上的策略：“湿亲和”和“干辅助亲和”固定。最后，还评估了用抗阿特拉津抗体本体修饰的新型抗阿特拉津免疫复合物的性能。通过在作为传感器的蛋白A（2%）石墨 - 环氧生物复合材料（ProtA(2%) - GEB）上进行“干辅助亲和”固定，实现了抗阿特拉津抗体更好的固定性能。在ProtA(2%) - GEB生物传感器上进行的用于检测阿特拉津的免疫反应基于使用阿特拉津 - HRP示踪剂作为酶标记的直接竞争分析。因此，通过合适的底物和酶HRP的介体实现电化学检测。使用加标橙汁样品成功评估了这种新策略。使用竞争电化学免疫传感分析测定橙汁中阿特拉津的检测限为6×10⁻³ μg L⁻¹（0.03 nmol L⁻¹），因此这种生物传感方法远远达到了欧盟关于饮用水和食品样品指令所要求的检测限（0.1 μg L⁻¹）。该策略为生物、食品和环境样品的快速、简单、经济高效的现场生物传感提供了巨大的前景。
