A dendrimer-based immunosensor for improved capture and detection of tumor necrosis factor-α cytokine

A dendrimer-based sandwich type enzyme-linked immunosorbent assay (ELISA) was developed for the improved detection of recombinant human tumor necrosis factor-alpha (TNF-alpha) for early diagnosis of perinatal diseases. Hydroxyl-terminated generation four poly(amidoamine) dendrimer (G4-OH) was used for the development of a solid phase bio-sensing platform. The surface of the ELISA plate was modified with polyethylene-glycol (PEG) and thiol-functionalized G4-OH was immobilized on the PEG-functionalized plate. A capture antibody was oxidized and covalently immobilized onto the dendrimer-modified ELISA plate, which provides favorable orientation for the antigen binding sites toward the analyte. The dendrimer-modified plate showed enhanced sensitivity, and the detection limit for TNF-alpha was found to be 0.48 pg mL(-1), which is significantly better than the commercially available ELISA kit. The selectivity of the dendrimer-modified ELISA plate was further evaluated with a mixture of cytokines, which showed results for similar to that of TNF-alpha alone. The modified plate provides a greater opportunity for the detection of a wide range of cytokines and biomarkers. (C) 2012 Elsevier B.V. All rights reserved.