title: Label-free immunoassay for porcine circovirus type 2 based on excessively tilted fiber grating modified with staphylococcal protein A.
abstract: Using excessively tilted fiber grating (Ex-TFG) inscribed in standard single mode fiber, we developed a novel label-free immunoassay for specific detection of porcine circovirus type 2 (PCV2), which is a minim animal virus. Staphylococcal protein A (SPA) was used to modify the silanized fiber surface thus forming a SPA layer, which would greatly enhance the proportion of anti-PCV2 monoclonal antibody (MAb) bioactivity, thus improving the effectiveness of specific adsorption and binding events between anti-PCV2 MAbs and PCV2 antigens. Immunoassay experiments were carried out by monitoring the resonance wavelength shift of the proposed sensor under different PCV2 titer levels. Anti-PCV2 MAbs were thoroughly dissociated from the SPA layer by treatment with urea, and recombined to the SPA layer on the sensor surface for repeated immunoassay of PCV2. The specificity of the immunosensor was inspected by detecting porcine reproductive and respiratory syndrome virus (PRRSV) first, and PCV2 subsequently. The results showed a limit of detection (LOD) for the PCV2 immunosensor of ~9.371TCID50/mL, for a saturation value of ~4.801×10(3)TCID50/mL, with good repeatability and excellent specificity.
authors: Chongqing Key Laboratory of Optical Fiber Sensor and Photoelectric Detection, Chongqing University of Technology, Chongqing 400054, China; School of Opto-electronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China; Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET, UK.
authors: Binbin
authors: B
authors: Luo
authors: School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China. Electronic address: sxwu2004@cqut.edu.cn.
authors: Shengxi
authors: S
authors: Wu
authors: Chongqing Key Laboratory of Optical Fiber Sensor and Photoelectric Detection, Chongqing University of Technology, Chongqing 400054, China.
authors: Wengen
authors: W
authors: Zou
authors: School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China.
authors: Zhonghao
authors: Z
authors: Zhang
authors: Chongqing Key Laboratory of Optical Fiber Sensor and Photoelectric Detection, Chongqing University of Technology, Chongqing 400054, China.
authors: Mingfu
authors: M
authors: Zhao
authors: Chongqing Key Laboratory of Optical Fiber Sensor and Photoelectric Detection, Chongqing University of Technology, Chongqing 400054, China.
authors: Shenghui
authors: S
authors: Shi
authors: School of Opto-electronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
authors: Yong
authors: Y
authors: Liu
authors: National Research Center for Veterinary Medicine, Henan 471003, China.
authors: Xiangfeng
authors: X
authors: Xi
authors: Chongqing Animal Disease Prevention and Control Center, Chongqing 401120, China.
authors: Zheng
authors: Z
authors: Zeng
authors: Chongqing Animal Disease Prevention and Control Center, Chongqing 401120, China.
authors: Wangwang
authors: W
authors: Liang
authors: Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET, UK.
authors: Zhijun
authors: Z
authors: Yan
authors: Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET, UK.
authors: Lin
authors: L
authors: Zhang
mesh_terms: D017925:Circovirus / Q000145:classification / Q000276:immunology* / Q000302:isolation & purification*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling; D013205:Staphylococcal Protein A / Q000276:immunology*
chemical_list: D013205:Staphylococcal Protein A
keywords: Excessively tilted fiber grating (Ex-TFG); Label-free immunoassay; Monoclonal antibody (MAb); Porcine circovirus type 2 (PCV2); Staphylococcal protein A (SPA)