In this study, a novel quantitative sandwich immunoassay for detecting cTn I was developed by using surface plasmon resonance biosensor and quantum dots(QD)-coupled antibody for the first time, which amplified the response of biosensor and so had the sensitivity of this method obviously improved. First quantum dots were coupled to the monoclonal antibody (2F11) against cTn I with N-hydroxysuccinimide (NHS and 1-ethyl-3-(3-dimethyl-aminopropyl)-carbodimidehydrochloride(EDC), and then the coupled product (QD-2F11) was confirmed by SDS-PAGE and its antibody activity was tested by protein blot. Finally, a sensitive sandwich immunosensing method for measuring cardiac troponin I was developed by surface plasmon resonance biosensor with protein A as an intermediate layer, the specific polyclonal antibody as the first antibody [capture antibody, and QD-labeled-monoclonal antibody as the second antibody(detecting antibody)]. The novel sandwich immunoassay showed the detection range of 0.4 to 15 mu g/L and a detection limit of 0.4 mu g/L, which is higher 2 times than the sandwich immunoassay without using QD-labeled antibody and 10 times than the direct immunoassay for cTn I previously developed, respectively.
[1]Jilin Univ, Coll Pharm, Changchun 130021, Peoples R China.
[2]Jilin Univ, Coll Elect Sci & Engn, Changchun 130012, Peoples R China.
[3]Jilin Univ, Coll Chem, Changchun 130012, Peoples R China.
[4]Jilin Univ, China Japan Union Hosp, Changchun 130033, Peoples R China.
(8.0+极速模式)