Sensitive ECL immunosensor for detection of retinol-binding protein based on double-assisted signal amplification strategy of multiwalled carbon nanotubes and Ru(bpy)32+ doped mesoporous silica nanospheres

• Published in: Biosensors & bioelectronics 2013-12, Vol.50, p.300-304
• Main Authors: Wu, Beina, Hu, Chenyi, Hu, Xiaoqing, Cao, Hongmei, Huang, Chusen, Shen, Hebai, Jia, Nengqin
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensors; Biotechnology; Clinical diagnostics; Electrochemiluminescence; Fundamental and applied biological sciences. Psychology; Mesoporous silica materials; Methods. Procedures. Technologies; Retinol-binding protein; Various methods and equipments
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2013.06.045

A novel electrochemiluminescence (ECL) strategy based on the sandwich-type immunosensor for sensitive detection of retinol-binding protein (RBP) was developed. The primary antibody anti-RBP was immobilized onto multiwalled carbon nanotubes (MWCNTs), which have large surface area and high electrical conductivity. The RBP antigen and Ru–Nafion@SiO2-labeled secondary antibody were then successively conjugated to form sandwich-type immunocomplexes through the specific interaction between antigen and antibody. The ECL signal amplification was significantly improved due to the synergistic effect of MWCNTs and mesoporous silica nanospheres (mSiO2). The developed ECL immunosensor exhibited high sensitivity and specificity for the detection of RBP and responded linearly to the clinically-relevant concentration of RBP from 78 to 5000ngmL−1. Moreover, the MWCNT-based ECL immunosensor displayed excellent stability and reproducibility, as well as successfully achieved the detection of RBP in patient urine samples with desirable results. The present work provided a promising technique for the clinical screening of RBP and point-of-care diagnostics. •An applicable and sensitive ECL immunoassay for RBP was developed.•Mesoporous SiO2 nanospheres with high monodispersity and uniform size were successfully synthesized by a modified Stöber sol–gel process.•Multiwalled carbon nanotubes (MWCNTs) were used to capture the primary antibody.•A specially designed Ru–Nafion@SiO2 composite nanoparticles labeled secondary antibody (Ab2) hybrid material was synthesized and used as a label.•The constructed immunosensor was applied to detect RBP in patient urine samples.