Electrochemical immunosensor constructed using TiO2 nanotubes as immobilization scaffold and tracing tag.
A ternary TiO2 nanotube (TNT) composite and a signal antibody and horseradish peroxidase (HRP) functionalized TNT were designed as an electrode scaffold for immobilization of high quantity of capture antibody and a tracing tag for immunosensing, respectively. The polyaniline (PANI) was coated on TNTs by chemical oxidative polymerization, and gold nanoparticles were deposited on TNT-PANI with a routine chemical reduction. Various techniques including scanning electron microscopy, energy dispersive X-ray, transmission electron microscope, X-ray diffraction, Fourier transform infrared spectra, X-ray photoelectron spectra, impedance and electrochemical techniques were used to characterize the nano-materials. Using bis(sulfosuccinimidyl) suberate as amino cross-linker, the TNT composite could be further functionalized with protein G' for oriented immobilization of capture antibody on electrode surface. Upon sandwich-type immunoreaction, the signal antibody on the tracing tag was quantitatively captured on the surface to generate sensitive electrochemical response with a H2O2 mediated HRP catalytic reaction. With α-fetoprotein as an analyte model, the immunosensor showed a linear range of 0.01-350ngmL(-1) with a detection limit of 1.5pgmL(-1). The accelerated electron transfer by the ternary composite, oriented immobilization of capture antibody and high loading of HRP on the TNT tracing tag greatly amplified the electrochemical signal, and led to the superior performance of the immunoassay.
Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China.
Xiaohe
X
Huo
Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China.
Peipei
P
Liu
Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China.
Jie
J
Zhu
Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province 475004, PR China. Electronic address: liuxiaoqiang@henu.edu.cn.
Xiaoqiang
X
Liu
State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210023, PR China. Electronic address: hxju@nju.edu.cn.
Huangxian
H
Ju
D000814:Aniline Compounds / Q000737:chemistry; D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D051379:Mice; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D014025:Titanium / Q000737:chemistry*; D000509:alpha-Fetoproteins / Q000032:analysis*
D000814:Aniline Compounds; D055910:Antibodies, Immobilized; D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D000509:alpha-Fetoproteins; C416807:polyaniline; C009495:titanium dioxide; D006046:Gold; D014025:Titanium
Immunosensor; Polyaniline; Protein G′; TiO(2) nanotube; α-fetoprotein