Solid-substrate room-temperature phosphorescence immunoassay based on an antibody labeled with nanoparticles containing dibromofluorescein luminescent molecules and analytical application.
Luminescent 20-nm silicon dioxide nanoparticles containing dibromofluorescein (D; particles denoted D-SiO(2)) were synthesized by the sol-gel method. In the presence of Pb(Ac)(2) as a heavy atom perturber, the particle can emit the intense and stable room temperature phosphorescence(RTP) signal on a polyamide membrane at the wavelength of lambdaex(max)/lambdaem(max) = 460/623 nm for D. Our research indicates that the specific immune reaction between goat-anti-human IgG antibody labeled with D-SiO(2) and human IgG can be carried out quantitatively on a polyamide membrane, and the phosphorescence intensity was evidently enhanced after the immunoreaction. Thus a new solid substrate-room temperature phosphorescence immunoassay (SS-RTP-IA) for determination of human IgG was established. The linear range of this method is 0.0624-20.0 pg spot(-1) of human IgG (corresponding to a concentration range of 0.156-50.0 ng ml(-1), sample volume: 0.40 microl spot(-1)). The regression equation of the working curve is DeltaIp = 94.39 + 17.00 m IgG (pg spot(-1)) (460/623 nm, r = 0.9998). Detection limit calculated as 3 Sb/k is 0.015 pg spot(-1). After elevenfold replicate measurement, RSD are 3.2% and 2.4% for samples containing 0.156 and 50.0 ng l(-1) IgG, respectively. This method is sensitive, accurate, and of high precision. And it has been applied to the determination of IgG in human serum with satisfactory results. Meanwhile, the mechanism of SS-RTP-IA based on an antibody labeled with nanoparticles containing dibromofluorescein luminescent molecules was discussed.
Liu
Jia-Ming
JM
Department of Chemistry, Zhangzhou Normal College, PR China. zzyliujiaming@163.com
Lu
Qiao-mei
QM
Wang
Yan
Y
Xu
Shan-shan
SS
Lin
Xiao-mei
XM
Li
Long-Di
LD
Lin
Shao-Qin
SQ
D000818:Animals; D000906:Antibodies / Q000737:chemistry* / Q000276:immunology; D001966:Bromine / Q000737:chemistry; D005452:Fluoresceins / Q000737:chemistry*; D006041:Goats; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis* / Q000097:blood / Q000276:immunology; D008163:Luminescent Measurements / Q000379:methods*; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry*; D009757:Nylons / Q000737:chemistry; D010316:Particle Size; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry
D000906:Antibodies; D005452:Fluoresceins; D007074:Immunoglobulin G; D008567:Membranes, Artificial; D009757:Nylons; D017640:Silicates; D012822:Silicon Dioxide; C005691:sodium silicate; D001966:Bromine