Tiamulin (TML) is a pleuromutilin antibiotic and mainly used to treat pulmonary and gastrointestinal infections. However, excessive use of TML can bring health threats to consumers. In this work, a label-free electrochemical immunosensor was proposed for sensitive detection of TML in pork and pork liver. Silver nanoparticles (AgNPs) were synthesized in situ on graphene oxide (GO), in which GO acted as a carrier for loading more AgNPs and AgNPs exhibited both strong conductivity and good redox property. In addition, staphylococcal protein A (SPA) was applied to oriented immobilization of fragment crystallizable (Fc) region of the TML monoclonal antibody. Under the optimal condition, the developed electrochemical immunosensor exhibited a good linear response with a concentration of TML ranging from 0.05 ng mL⁻¹ to 100 ng mL⁻¹ and the limit of detection (LOD) was 0.04 ng mL⁻¹. Furthermore, the designed immunosensor was applied to detect TML in real samples with a good accuracy. Therefore, the label-free electrochemical immunosensor could be used as a potential method to detect TML and other antibiotic residues in animal derived foods.

Tiamulin (TML) 是一种截短侧耳素抗生素，主要用于治疗肺部和胃肠道感染。然而，过度使用TML会给消费者带来健康威胁。在这项工作中，提出了一种无标记电化学免疫传感器，用于灵敏检测猪肉和猪肝中的 TML。在氧化石墨烯 (GO) 上原位合成银纳米粒子 (AgNPs)，其中 GO 作为载体加载更多的 AgNPs，AgNPs 表现出强导电性和良好的氧化还原性能。此外，将葡萄球菌蛋白 A (SPA) 应用于 TML 单克隆抗体的可结晶片段 (Fc) 区的定向固定。在最佳条件下，所开发的电化学免疫传感器表现出良好的线性响应，TML 浓度范围为 0.05 ng mL ^-1至 100 ng mL ^-1且检测限 (LOD) 为 0.04 ng mL ^-1。此外，设计的免疫传感器用于检测真实样品中的 TML，具有良好的准确性。因此，无标记电化学免疫传感器可作为检测动物源性食品中TML和其他抗生素残留的潜在方法。