title: Label-free colorimetric immunoassay for the simple and sensitive detection of neurogenin3 using gold nanoparticles.
abstract: Neurogenin3 (ngn3), as a marker for pancreatic endocrine precursor cells and an essential ingredient in the development of islet cells, was quantitatively detected for the first time. Based on a non-cross-linking specific interaction mechanism, a label-free colorimetric immunoassay for the synthetic peptide fragment of ngn3 (SKQRRSRRKKAND) using glutathione (-Glu-Cys-Gly, GSH) functionalized gold nanoparticles (GNPs) is reported. The anti-ngn3 antibody conjugated GNPs (GNP-Ab) was formed through electrostatic interaction upon the addition of anti-ngn3 antibody to the GSH-modified GNPs solution. Monobinding of the positively charged ngn3 to the negatively charged GNP-Ab will minimize the electrostatic repulsion between nanoparticles by neutralizing the surface charge, and then agglomeration is induced by an increasing salt concentration. Under the optimal conditions, the assay showed a linear response range of 50-300 ng/mL for the peptide with a detection limit being 20 ng/mL. The preliminary study on ngn3 opens up an innovative insight to detect short synthetic peptide fragment of antigen, and may own an opportunity for practical applications in clinical diagnosis and therapeutics.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. yuanyue@ciac.jl.cn
authors.forename: Yue
authors.initials: Y
authors.lastname: Yuan
authors.forename: Jia
authors.initials: J
authors.lastname: Zhang
authors.forename: Hanchang
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiurong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D051792:Basic Helix-Loop-Helix Proteins / Q000032:analysis* / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D003124:Colorimetry / Q000379:methods* / Q000706:statistics & numerical data; D006046:Gold; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D057230:Limit of Detection; D053768:Metal Nanoparticles; D051379:Mice; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000276:immunology; D010446:Peptide Fragments / Q000032:analysis / Q000276:immunology; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D051792:Basic Helix-Loop-Helix Proteins; D006046:Gold; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C498695:NEUROG3 protein, human