Dispersing gold nanoparticles on thiolated polyaniline-multiwalled carbon nanotubes for development of an indole-3-acetic acid amperometric immunosensor

Zhaohong Su; Yongbing Cheng; Chaorong Li; Yuanfu Xiong; Langtao Xiao; Shu Chen; Xiaoli Qin

doi:10.1039/c9na00258h

Dispersing gold nanoparticles on thiolated polyaniline-multiwalled carbon nanotubes for development of an indole-3-acetic acid amperometric immunosensor

Nanoscale Adv. 2019 Jul 24;1(9):3607-3613. doi: 10.1039/c9na00258h. eCollection 2019 Sep 11.

Authors

Zhaohong Su¹, Yongbing Cheng¹, Chaorong Li¹, Yuanfu Xiong¹, Langtao Xiao², Shu Chen³, Xiaoli Qin¹

Affiliations

¹ College of Science, Hunan Agricultural University Changsha 410128 PR China zhaohongsu@hunau.edu.cn qinxl@hunau.edu.cn.
² Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology, Hunan Agricultural University Changsha 410128 PR China.
³ Key Laboratory of Theoretical Organic Chemistry and Function Molecule of Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology Xiangtan 411201 PR China.

Abstract

An amperometric immunosensor based on new thiolated bionanocomposite with a high dispersion of gold nanoparticles (AuNPs) for the sensitive detection of indole-3-acetic acid (IAA) is being reported herein. Briefly, a thiolated nanocomposite was prepared via the microwave-assisted thiol-ene reaction of 2,5-dimercapto-1,3,4-thiadiazole (DMcT) with oxidized polyaniline (PANI), which was synthesized in the presence of multiwalled carbon nanotubes (MWCNTs), yielding thiolated polyaniline (TPANI)-MWCNTs. Further, AuNPs were deposited on the TPANI-MWCNTs by microwave-assisted method to obtain a AuNPs/TPANI-MWCNTs nanocomposite. Finally, the thiolated bionanocomposite film was constructed via the specific chemical reaction between boronic acid functionalized AuNPs and the vicinal diol functionalized AuNP labeled immunoglobulin G (IgG-AuNPs). The change in the reduction peak current of Fe(CN)₆ ^3- was used to monitor the immunoreaction between IAA and antibody. The TPANI-MWCNT nanocomposites uniformly disperse AuNPs, IgG-AuNPs and anti-IAA-AuNPs, leading to the amplification of the signal of the immunosensor. Fourier transform infrared spectra (FTIR), cyclic voltammetry (CV), transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV-vis) and differential pulse voltammetry (DPV) were used to characterize the nanocomposite film and the stepwise modification of the immunosensor. The prepared thiolated bionanocomposite material has good biocompatibility, a highly uniform dispersion of the AuNPs with a narrow size distribution as verified by TEM, and high load/activity of the immobilized antibody proved via DPV. The fabricated IAA amperometric immunosensor not only exhibits a good linear arrange from 1.0 pg mL^-1 to 10 ng mL^-1 with the limit of detection of 0.97 pg mL^-1 (S/N = 3), but also possesses good selectivity, reproducibility and stability for the detection of IAA.