title: Application of inductively coupled plasma mass spectrometry in the study of apoptosis: determination of caspase-3 using a gold nanoparticle tag.
abstract: Apoptosis is a main type of cell death in which caspase-3 plays a key role. In this work, a simple, fast and sensitive immunoassay for caspase-3 is established by using inductively coupled plasma mass spectrometry (ICP-MS) detection and signal enhancement gold nanoparticle (Au-NP) labelling of the secondary antibody (IgG). After the immunoreaction of caspase-3, primary antibody and Au-NP labeled IgG, the concentration of caspase-3 was determined by ICP-MS analysis of the Au-NPs released from the immunocomplex. Under the optimized conditions, a limit of detection (LOD, 3σ) of 0.42 ng mL(-1) (0.31 nM) was obtained for caspase-3, with a dynamic range of 1-200 ng mL(-1) and a relative standard deviation of 4.1% (c = 5 ng mL(-1), n = 11). The proposed method has good specificity towards caspase-3. To demonstrate the application potential of the proposed method, the cell lysates of Hg(2+)-induced HepG2 cells were analyzed, and it was found that the concentration of caspase-3 increased when increasing the incubation concentration of Hg(2+). This method is easy, sensitive and selective, and has excellent capability of tolerating a complex biological matrix, indicating the potential of the ICP-MS-based assay in the study of apoptosis.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, P R China. binhu@whu.edu.cn.
authors.forename: Zhengru
authors.initials: Z
authors.lastname: Liu
authors.forename: Beibei
authors.initials: B
authors.lastname: Chen
authors.forename: Man
authors.initials: M
authors.lastname: He
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Han
authors.initials: H
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology; D013058:Mass Spectrometry / Q000379:methods*; D008628:Mercury / Q000494:pharmacology; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D007074:Immunoglobulin G; D006046:Gold; D053148:Caspase 3; D008628:Mercury