title: Label-free electrochemical immunoassay of Bcl-2 protein expression on tumor cells.
abstract: Bcl-2 protein is one of the anti-apoptotic members in Bcl-2 family proteins. It can regulate apoptosis in response to a wide variety of toxic agents, which has a close relationship with drug-resistance of tumor cells. Electrochemical impedance spectroscopy measurements were employed to quantify the cell concentration and analyze the expression of Bcl-2 protein on tumor cells and drug-resistant tumor cells based on the competitive immunoassay. Bcl-2 antibody and bovine serum albumin were adsorbed on Au nanoparticles to construct nanocomposites that could be captured on the Bcl-2 protein modified electrode. The binding of the nanocomposites resulted in a great increase of the charge-transfer resistance (Rct) due to the strong steric hindrance effect and this effect was inhibited in the presence of MCF-7 cells and MCF-7/ADR cells owing to the competitive immunoreaction between the nanocomposites and Bcl-2 proteins on cells. Under the optimal conditions, the charge-transfer resistance change (ΔRct) is proportional to the logarithm of the cells concentration from 5×10(2) to 1.6×10(6) cell mL(-1) with a detection limit of 170 cell mL(-1). The expression of Bcl-2 protein on MCF-7/ADR cells was found to be significantly higher than that in MCF-7 cells, indicating that the up-regulation of Bcl-2 protein is one of characteristics of drug-resistant tumor cells.
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Lina
authors.initials: L
authors.lastname: Chen
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Huoliang
authors.initials: H
authors.lastname: Gu
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China; Department of Chemistry, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China. Electronic address: liangtan@hunnu.edu.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Tan
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D058266:Dielectric Spectroscopy / Q000379:methods*; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004566:Electrodes; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D057230:Limit of Detection; D061986:MCF-7 Cells; D053761:Nanocomposites / Q000737:chemistry; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*
chemical_list: D000903:Antibiotics, Antineoplastic; C000595707:BCL2 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D006046:Gold; D004317:Doxorubicin
keywords: Bcl-2 protein; Competitive immunoassay; Drug-resistance; Electrochemical impedance spectroscopy; Tumor cells