title: Microchip-based immunoassays with application of silicon dioxide nanoparticle film.
abstract: Highly sensitive detection of proteins offers the possibility of early and rapid diagnosis of various diseases. Microchip-based immunoassay integrates the benefits from both immunoassays (high specificity of target sample) and microfluidics (fast analysis and low sample consumption). However, direct capture of proteins on bare microchannel surface suffers from low sensitivity due to the low capacity of microsystem. In this study, we demonstrated a microchip-based heterogeneous immunoassay using functionalized SiO(2) nanoparticles which were covalently assembled on the surface of microchannels via a liquid-phase deposition technique. The formation of covalent bonds between SiO(2) nanoparticles and polydimethylsiloxane substrate offered sufficient stability of the microfluidic surface, and furthermore, substantially enhanced the protein capturing capability, mainly due to the increased surface-area-to-volume ratio. IgG antigen and FITC-labeled anti-IgG antibody conjugates were adopted to compare protein-enrichment effect, and the fluorescence signals were increased by ~75-fold after introduction of functionalized SiO(2) nanoparticles film. Finally, a proof-of-concept experiment was performed by highly efficient capture and detection of inactivated H1N1 influenza virus using a microfluidic chip comprising highly ordered SiO(2) nanoparticles coated micropillars array. The detection limit of H1N1 virus antigen was 0.5 ng mL(-1), with a linear range from 20 to 1,000 ng mL(-1) and mean coefficient of variance of 4.71%.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
authors.forename: Qin-Shu
authors.initials: QS
authors.lastname: Kang
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Sun
authors.forename: Li-Jin
authors.initials: LJ
authors.lastname: Su
authors.forename: Zhen-Hua
authors.initials: ZH
authors.lastname: Zheng
authors.forename: Zhen-Feng
authors.initials: ZF
authors.lastname: Zhang
authors.forename: Han-Zhong
authors.initials: HZ
authors.lastname: Wang
authors.forename: Zhi-Ke
authors.initials: ZK
authors.lastname: He
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Huang
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis / Q000276:immunology; D004867:Equipment Design; D016650:Fluorescein-5-isothiocyanate / Q000032:analysis; D006041:Goats; D007118:Immunoassay / Q000295:instrumentation*; D007074:Immunoglobulin G / Q000276:immunology; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology / Q000302:isolation & purification*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009976:Orthomyxoviridae Infections / Q000175:diagnosis* / Q000276:immunology; D011817:Rabbits; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; C048844:anti-IgG; D012822:Silicon Dioxide; D016650:Fluorescein-5-isothiocyanate