Ultrasensitive colorimetric immunoassay for hCG detection based on dual catalysis of Au@Pt core–shell nanoparticle functionalized by horseradish peroxidase

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 193; pp. 102 - 108
• Main Authors: Wang, Weiguo, Zou, Yake, Yan, Jinwu, Liu, Jing, Chen, Huixiong, Li, Shan, Zhang, Lei
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.03.2018
• Subjects: Au@Pt nanoparticles; Colorimetric detection; Dual catalysis; Horseradish peroxidase; Signal amplification; Dual catalysis; Horseradish peroxidase; Au@Pt nanoparticles; Signal amplification; Colorimetric detection
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2017.12.014

In this paper, an ultrasensitive colorimetric biosensor for human chorionic gonadotrophin (hCG) detection was designed from bottom-up method based on the dual catalysis of the horseradish peroxidase (HRP) and Au@Pt nanoparticles (NPs) relative to H2O2-TEM system. HRP and monoclonal mouse anti-hCG antibody (β-submit, mAb1) were co-immobilized onto the Au@Pt NP surface to improve catalytic efficiency and specificity, which formed a dual functionalized Au@Pt-HRP probe with the mean size of 42.8nm (D50). The colorimetric immunoassay was developed for the hCG detection, and the Au@Pt-HRP probe featured a higher sensitivity in the concentration range of 0.4–12.8IUL−1 with a low limit of detection (LOD) of 0.1IUL−1 compared with the LODs of 0.8IUL−1 for BA-ELISA and of 2.0IUL−1 for Au@Pt, which indicated that the Au@Pt-HRP probe possessed higher catalytic efficiency with 2.8-fold increase over Au@Pt and 33.8-fold increase over HRP. Also, the Au@Pt-HRP probe exhibited good precision and reproducibility, high specificity and acceptable accuracy with CV being less than 15%. The dual functionalized Au@Pt-HRP probe as a type of signal amplified method was firstly applied in the colorimetric immunoassay for the hCG detection. [Display omitted] •The dual catalysis of Au@Pt-HRP probe was first applied in the colorimetric immunoassay for the hCG detection.•Au@Pt NPs was a good carrier for the signal amplification and about 21-22 HRP molecules could be absorbed on the surface of Au@Pt NP.•The Au@Pt-HRP probe featured a higher sensitivity in the concentration range of 0.4–12.8 IU L-1 with a LOD of 0.1 IU L-1.