title: An ultrasensitive fluorescence assay for protein detection by hybridization chain reaction-based DNA nanotags.
abstract: An ultrasensitive fluorescence method for determination of protein is developed based on hybridization chain reaction (HCR). In this assay, the streptavidin-magnetic nanobeads were conjugated to biotinylated initiators and biotinylated anti-IgG. In the presence of human IgG, the magnetic nanobeads were fixed on the substrate and the carried initiators propagated the chain reaction of hybridization to form the nicked polymers. Because the nanobead probe carries with a large number of oligonucleotides per protein binding event, there is obvious amplification in the nicked polymers. Then, numerous SYBR Green I molecules were intercalated into the grooves of the long dsDNA polymers, generating a substantially apparent increase in the corresponding fluorescence intensity. With HCR amplification and magenetic nanobead to preamplify the fluorescence signal and reduce the background signal, the detection limit of this assay was 14 aM. Compared with the reported protein detection methods, our method exhibited ultrahigh sensitivity. In addition, the proposed method possessed excellent selectivity and low matrix effect. What is more, the assay was also studied for clinical application in human serum with a satisfactory and reliable result.
authors.affiliation: Key Laboratory of Natural Products Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, 250012 Jinan, PR China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Dai
authors.forename: Qingwang
authors.initials: Q
authors.lastname: Xue
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.forename: Yongshun
authors.initials: Y
authors.lastname: Ding
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000737:chemistry; D052160:Benzothiazoles; D015374:Biosensing Techniques / Q000379:methods*; D019921:Biotinylation; D004247:DNA / Q000737:chemistry; D003959:Diamines; D005453:Fluorescence; D015200:Fluoroimmunoassay / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D057230:Limit of Detection; D009693:Nucleic Acid Hybridization / Q000379:methods; D009930:Organic Chemicals / Q000737:chemistry; D011804:Quinolines; D019809:Streptavidin / Q000737:chemistry
chemical_list: D000888:Antibodies, Anti-Idiotypic; D052160:Benzothiazoles; D003959:Diamines; D007074:Immunoglobulin G; D009930:Organic Chemicals; D011804:Quinolines; C048844:anti-IgG; C098022:SYBR Green I; D004247:DNA; D019809:Streptavidin
keywords: Enzyme-free; Fluorescence signal; Human IgG; Hybridization chain reaction