title: Antibody modified gold nano-mushroom arrays for rapid detection of alpha-fetoprotein.
abstract: Localized surface plasmon resonance (LSPR) combined with immunoassay shows greatly potential in fast detection of tumor markers. In this paper, a highly sensitive LSPR substrate has been fabricated and modified for direct detection of alpha-fetoprotein (AFP). The biosensor was prepared by interference lithography, and modified by covalently immobilizing anti-AFP on the surface of gold nano-mushroom arrays (GNMA). The modification process was investigated by Vis-NIR reflectance spectra and cyclic voltammogram measurements. We revealed the optical properties of the modified GNMA by measuring the Vis-NIR reflectance spectra and simulating its electric intensity field distribution under light illumination. The GNMA substrate was highly sensitive, with a refractive index sensitivity of ~465 nm/RIU. The substrate can be applied to label-free detection of AFP, with the linear range and the limit of detection determined to be 20-200 ng/mL and 24 ng/mL (S/N=3), respectively. We also demonstrated its clinical application by directly detecting AFP in human serum samples. It is expected that our biosensor could be integrated on microfluidic chips for high-throughput detection in portable early diagnosis, post-operative and point-of-care (POC) in clinical applications.
authors.affiliation: Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Engineering, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Wanbo
authors.initials: W
authors.lastname: Li
authors.affiliation: Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Engineering, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Jiancai
authors.initials: J
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
authors.forename: Zhangkai
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Sensing Technology and Biomedical Instruments of Guangdong Province, School of Engineering, Sun Yat-sen University, Guangzhou 510275, China. Electronic address: zhoujh33@mail.sysu.edu.cn.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhou
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry*; D015374:Biosensing Techniques; D006046:Gold / Q000737:chemistry; D006801:Humans; D049329:Nanostructures / Q000737:chemistry; D020349:Surface Plasmon Resonance; D000509:alpha-Fetoproteins / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D055910:Antibodies, Immobilized; D000509:alpha-Fetoproteins; D006046:Gold
keywords: Alpha-fetoprotein; Biosensor; Gold nano-mushroom arrays; Immunoassay; Localized surface plasmon