title: An Improved Label-Free Indirect Competitive SPR Immunosensor and Its Comparison with Conventional ELISA for Ractopamine Detection in Swine Urine.
abstract: Ractopamine (RCT) is banned for use in animals in many countries, and it is urgent to develop efficient methods for specific and sensitive RCT detection. A label-free indirect competitive surface plasmon resonance (SPR) immunosensor was first developed with a primary antibody herein and then improved by a secondary antibody for the detection of RCT residue in swine urine. Meanwhile, a pre-incubation process of RCT and the primary antibody was performed to further improve the sensitivity. With all the key parameters optimized, the improved immunosenor can attain a linear range of 0.3-32 ng/mL and a limit of detection (LOD) of 0.09 ng/mL for RCT detection with high specificity. Furthermore, the improved label-free SPR immunosenor was compared thoroughly with a conventional enzyme-linked immunosorbent assay (ELISA). The SPR immunosensor showed advantages over the ELISA in terms of LOD, reagent consumption, analysis time, experiment automation, and so on. The SPR immunosensor can be used as potential method for real-time monitoring and screening of RCT residue in swine urine or other samples. In addition, the design using antibody pairs for biosensor development can be further referred to for other small molecule detection.
authors.affiliation: Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China. lqfhws@163.com.
authors.forename: Sai
authors.initials: S
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China. zhaoshuaibuct@163.com.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China. weixiaobuct@163.com.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wei
authors.affiliation: Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China. zhangshanbuctbuct@163.com.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China. liujiahuibuct@163.com.
authors.forename: Jiahui
authors.initials: J
authors.lastname: Liu
authors.affiliation: Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China. yydong@mail.buct.edu.cn.
authors.forename: Yiyang
authors.initials: Y
authors.lastname: Dong
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D010627:Phenethylamines; D020349:Surface Plasmon Resonance; D013552:Swine
chemical_list: D010627:Phenethylamines; C060897:ractopamine
keywords: ELISA; SPR immunosensor; ractopamine; swine urine