A MoS 2 nanoflower and gold nanoparticle-modified surface plasmon resonance biosensor for a sensitivity-improved immunoassay

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2020-05, Vol.8 (20), p.6861-6868
• Main Authors: Zhao, Peili, Chen, Yaofei, Chen, Yu, Hu, Shiqi, Chen, Hui, Xiao, Wei, Liu, Guishi, Tang, Yong, Shi, Jifu, He, Zhendan, Luo, Yunhan, Chen, Zhe
• Format: Article
• Language: English
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/D0TC00556H

Biosensors based on surface plasmon resonance (SPR) have shown significant applications in drug screening, environmental monitoring, immunoassay, etc. ; however, improving the sensitivity of these biosensors is one of the prime tasks at present. In this study, taking advantage of the special optical and morphological characteristics of MoS 2 nanoflowers, we synthesized a sensitivity-improved SPR biosensor by successively depositing MoS 2 nanoflowers and gold nanoparticles (AuNPs) on a traditional SPR sensor and then applied this biosensor to the immunoassay of mouse IgG. It was found that the deposition of the MoS 2 nanoflowers could improve the bulk refractive index sensitivity from 2212.2 to 2857.2 nm per RIU (RIU: refractive index unit); however, the further addition of AuNPs resulted in a decrease in the bulk refractive index sensitivity to 2149.7 nm per RIU. Moreover, when the proposed biosensor was applied to the IgG immunoassay, a 0.047 nm (μg mL −1 ) −1 sensitivity of the MoS 2 –AuNP-modified sensor was achieved, which was ∼3 times that of the unmodified sensor (0.016 nm (μg mL −1 ) −1 ). This improvement in the sensitivity of the biosensor towards IgG can be attributed to the flower-like morphology of MoS 2 that provides more sites for the loading of AuNPs, thus facilitating the immobilization of a larger amount of IgG antibody on the surface of the sensor. Because of its simple fabrication process and compatibility with the standard bio-activation method of gold surface, the proposed biosensor provides an easily-accessible platform for biological analysis and detection with improved sensitivity.