One-step synthesis of triethanolamine-capped Pt nanoparticle for colorimetric and electrochemiluminescent immunoassay of SARS-CoV spike proteins

• Published in: Microchemical journal 2023-03, Vol.186, p.108329, Article 108329
• Main Authors: Yang, Xiaolan, Li, Xiangyu, He, Qingguo, Ding, Yanbin, Luo, Bin, Xie, Qiuju, Chen, Jiahao, Hu, Yue, Su, Zhaohong, Qin, Xiaoli
• Format: Article
• Language: English
• Subjects: Colorimetry; Electrochemiluminescence; Immunoassay; Platinum nanoparticles; Triethanolamine
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2022.108329

[Display omitted] •A simple and one-step synthesis of novel TEOA-capped PtNPs was proposed.•The enzyme-mimetic activity and enhancing ECL property of TEOA@PtNPs were studied.•Sensitive colorimetric and ECL immunosensors of SARS-CoV S-protein were conducted. Platinum nanoparticles (PtNPs) have been attracted worldwide attention due to their versatile application potentials, especially in the catalyst and sensing fields. Herein, a facile synthetic method of triethanolamine (TEOA)-capped PtNPs (TEOA@PtNP) for electrochemiluminescent (ECL) and colorimetric immunoassay of SARS-CoV spike proteins (SARS-CoV S-protein, a target detection model) is developed. Monodisperse PtNPs with an average diameter of 2.2 nm are prepared by a one-step hydrothermal synthesis method using TEOA as a green reductant and stabilizer. TEOA@PtNPs can be used as a nanocarrier to combine with antigen by the high-affinity antibody, which leads to a remarkable inhibition of electron transfer efficiency and mass transfer processes. On the basis of its peroxidase-like activity and easy-biolabeling property, the TEOA@PtNP can be used to establish a colorimetric immunosensor of SARS-CoV S-protein thought catalyzing the reaction of H2O2 and 3,3′,5,5′-tetramethylbenzidine (TMB). Especially, the Ru(bpy)32+ ECL reaction is well-achieved with the TEOA@PtNPs due to their great conductivity and loading abundant TEOA co-reactants, resulting in an enhancing ECL signal in immunoassay of SARS-CoV S-protein. As a consequence, two proposed methods could achieve sensitive detection of SARS-CoV S-protein in wide ranges, the colorimetric and ECL detection limits were as low as 8.9 fg /mL and 4.2 fg /mL (S/N = 3), respectively. We believe that the proposed colorimetric and ECL immunosesors with high sensitivity, good reproducibility, and good stability will be a promising candidate for a broad spectrum of applications.