title: Electrochemiluminescence immunosensor for ultrasensitive detection of biomarker using Ru(bpy)(3)(2+)-encapsulated silica nanosphere labels.
abstract: Here, we describe a new approach for electrochemiluminescence (ECL) assay with Ru(bpy)(3)(2+)-encapsulated silica nanoparticle (SiO(2)@Ru) as labels. A water-in-oil (W/O) microemulsion method was employed for one-pot synthesis of SiO(2)@Ru nanoparticles. The as-synthesized SiO(2)@Ru nanoparticles have a narrow size distribution, which allows reproducible loading of Ru(bpy)(3)(2+) inside the silica shell and of alpha-fetoprotein antibody (anti-AFP), a model antibody, on the silica surface with glutaraldehyde as linkage. The silica shell effectively prevents leakage of Ru(bpy)(3)(2+) into the aqueous solution due to strong electrostatic interaction between the positively charged Ru(bpy)(3)(2+) and the negatively charged surface of silica. The porous structure of silica shell allowed the ion to move easily through the pore to exchange energy/electrons with the entrapped Ru(bpy)(3)(2+). The as-synthesized SiO(2)@Ru can be used as a label for ultrasensitive detection of biomarkers through a sandwiched immunoassay process. The calibration range of AFP concentration was 0.05-30 ng mL(-1) with linear relation from 0.05 to 20 ng mL(-1) and a detection limit of 0.035 ng mL(-1) at 3sigma. The resulting immunosensors possess high sensitivity and good analytical performance.
authors.affiliation: School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.forename: Zhenxian
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Cao
authors.forename: Songqin
authors.initials: S
authors.lastname: Liu
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry; D055910:Antibodies, Immobilized / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis; D056831:Coordination Complexes; D006046:Gold / Q000737:chemistry; D007118:Immunoassay; D008163:Luminescent Measurements / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D000509:alpha-Fetoproteins / Q000276:immunology; D017975:Ruthenium Compounds
chemical_list: D015082:2,2'-Dipyridyl; D055910:Antibodies, Immobilized; D015415:Biomarkers; D056831:Coordination Complexes; D006046:Gold; D012822:Silicon Dioxide; D000509:alpha-Fetoproteins; C547232:tris(2,2-bipyridine)-ruthenium(II); D017975:Ruthenium Compounds