A sandwich-type electrochemical immunosensor based on spherical nucleic acids-templated Ag nanoclusters for ultrasensitive detection of tumor biomarker

• Published in: Biosensors & bioelectronics Vol. 223; p. 115029
• Main Authors: Chen, Huinan, Li, Yuanyuan, Song, Yuchen, Liu, Fujing, Deng, Dongmei, Zhu, Xiaoli, He, Haibo, Yan, Xiaoxia, Luo, Liqiang
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.03.2023
• Subjects: Ag nanoclusters; Antibodies; Biomarkers, Tumor; Biosensing Techniques - methods; Electrochemical Techniques - methods; Gold; Graphite; Humans; Immunoassay - methods; Immunosensor; Limit of Detection; Metal Nanoparticles; Nucleic Acids; Signal amplifying; Spherical nucleic acids; Tumor biomarker; Signal amplifying; Tumor biomarker; Spherical nucleic acids; Ag nanoclusters; Immunosensor
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2022.115029

The accurate determination of tumor biomarkers in blood is of vital significance in the diagnosis and therapy of tumor disease. In this research, an innovative sandwich-type electrochemical immunosensor is designed for the ultrasensitive determination of tumor biomarker AFP using spherical nucleic acids-templated silver nanoclusters (AgNCs) sensing platform. For this purpose, on one hand, DNA functionalized gold nanoparticles (AuNPs@DNA) is selected not only as the cross-linker to immobilize the primary antibody (anti-AFP antibody 1, Ab1) to obtain AuNPs@DNA-Ab1, but also as the template for synthesizing AgNCs on AuNPs to form AuNPs@DNA-AgNCs. On the other hand, p-sulfonated calix[4]arene (pSC4) modified Au is chosen to immobilize the secondary antibody (anti-AFP antibody 2, Ab2) through host-guest recognition between Ab2 and pSC4. When AFP is encountered, the immunoreaction signal can be significantly amplified by the electrochemical reduction of AgNCs. Under optimal circumstances, the sandwich-type electrochemical immunosensor exhibits broad limit of linearity from 0.001 to 100 ng mL−1 (R2 = 0.997) and low detection limit of 7.74 fg mL−1 (S/N = 3). The immunosensor possesses excellent repeatability and selectivity, offering a novel method for sensitive clinical diagnosis of tumor markers in human hepatocellular carcinoma. [Display omitted]