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%.

Rapid and Sensitive Detection of H1N1/2009 Virus from Aerosol Samples with a Microfluidic Immunosensor

“…With this three-sigma rule, the detection limit was less than 1 pg/mL, significantly lower than most other studies (0.5 ng/mL to 1 µg/mL). 6–8…”

“…With this three-sigma rule, the detection limit was less than 1 pg/mL, significantly lower than most other studies (0.5 ng/mL to 1 µg/mL). [6][7][8] The same standard curve was constructed using a cell phone camera as an optical detector. The actual cell phone images were shown underneath the graph, for PBS and the 100-pg/mL H1N1 solution.…”

“…Most commercial rapid kits that use membrane immunoassay (i.e., lateral-flow assay) show the detection limit of 10 3.3 to 10 4.7 TCID 50 /mL, 7 much inferior to the PCR methods. Li et al 8 used nanoparticles to improve the detection limit down to 0.5 ng/mL antigens, but they used isolated antigens rather than patient sample.…”

Enzyme-Antibody-Modified Gold Nanoparticle Probes for the Ultrasensitive Detection of Nucleocapsid Protein in SFTSV

“…In this context, nanotechnology offers many ways to improve detection sensitivity. Nanomaterials, such as gold nanoparticles (AuNPs) [ 16 ], magnetic beads [ 17 ], graphene oxide [ 18 ], Polyamidoamine dendrimer (PAMAM) [ 19 ], silica [ 20 ], and plasmonic nanoparticles [ 21 ] can be used for detection applications [ 15 ]. AuNPs are distinguished from other nanoparticles and quantum dots containing harmful heavy metal ions because of their simpler synthesis process and effective surface modification [ 22 ].…”

Comparative cytotoxicity and genotoxicity of cobalt (II, III) oxide, iron (III) oxide, silicon dioxide, and aluminum oxide nanoparticles on human lymphocytes in vitro

“…6 SiO 2 NPs are used in the biomedical field such as DNA delivery, additives to drugs, cancer therapy, enzyme immobilization, and biosensors. 7,8 Al 2 O 3 NPs have a broad range of applications in aircrafts, ceramic industry, catalysis, biomaterials, and drugs. 9,10 The Co 3 O 4 NPs can easily penetrate and cause damage to the skin than the bulk material.…”