title: Electrochemical immunosensor for tumor necrosis factor-alpha detection in undiluted serum.
abstract: An immunosensor for the sensitive detection and estimation of tumor necrosis factor-alpha (TNF-α) in undiluted serum has been developed via an electrochemical enzyme-linked immunosorbent assay (ELISA) process. Electrochemical sensing was performed using a TNF-α specific monoclonal antibody modified self-assembled monolayer of dithiobis(succinimidyl propionate) on a comb-shaped gold electrode microarray. After anti-TNF-α antibody binding, unreacted active groups of DTSP were blocked using ethanol amine (EA) and nonspecific binding was prevented using phosphate buffer based starting block T20 (SB). Sensitive and disposable SB-EA-anti-TNF-α/DTSP/Au electrodes were exposed to solutions with different TNF-α concentrations for 20min in undiluted serum. Conversion of 4-aminophenyl phosphate to 4-aminophenol and its electrochemical oxidation was utilized for indirect estimation of TNF-α. Results for SB-anti-TNF-α/DTSP/Au electrodes indicate that the sensors can be used for the sensitive estimation of TNF-α in undiluted serum in the range 500pg/ml to 100ng/ml with a detection limit of 60pg/ml and sensitivity of 0.46 (ng/ml)-1. Negligible interference from serum and other biomarker proteins was observed. The described electrochemical ELISA is much faster than conventional ELISA and can be applied for sensing of a range of analytes in real patient samples.
authors.affiliation: Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom. Electronic address: sunilarya333@gmail.com.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Arya
authors.affiliation: Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom. Electronic address: P.Estrela@bath.ac.uk.
authors.forename: Pedro
authors.initials: P
authors.lastname: Estrela
mesh_terms: D000627:Aminophenols / Q000737:chemistry; D000814:Aniline Compounds / Q000737:chemistry; D055910:Antibodies, Immobilized / Q000737:chemistry; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D004566:Electrodes; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D019856:Ethanolamine / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D009943:Organophosphorus Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D011485:Protein Binding; D013388:Succinimides / Q000737:chemistry; D014409:Tumor Necrosis Factor-alpha / Q000097:blood*
chemical_list: D000627:Aminophenols; D000814:Aniline Compounds; D055910:Antibodies, Immobilized; D000911:Antibodies, Monoclonal; D009943:Organophosphorus Compounds; D013388:Succinimides; D014409:Tumor Necrosis Factor-alpha; D019856:Ethanolamine; C068798:4-aminophenylphosphate; D006046:Gold; C011240:dithiobis(succinimidylpropionate); C026729:4-aminophenol
keywords: Dithiobis(succinimidyl propionate); Electrochemical ELISA; Immunoassay; Serum; TNF-α