Direct detection of TNF-α by copper benzene tricarboxylate MOFs/gold nanoparticles modified electrochemical label-free immunosensor using FFT admittance voltammetry

Abstract

A new simple label-free electrochemical immunosensor was designed for sensitive and selective determination of tumor necrosis factor-alpha (TNF-α), through gold nanoparticles (GNPs) incorporated copper benzene tricarboxylate metal organic frameworks (HKUST-1) modified gold electrode, where TNF-α specific monoclonal antibody was bonded to the electrode surface through shaped self-assembled monolayer (SAM) of mercapto compounds. The fabrication steps were monitored by field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimized experimental conditions, fast Fourier transform admittance voltammetry (FFTADV) used for TNF-α measurement. A wide linear range of current response towards the TNF-α concentration from 0.0005 to 50 ng/mL and LOD value of 0.15 pg/mL were achieved using FFTADV. The described immunosensor had adequate sensitivity and selectivity towards direct determination of TNF-α in complex biological matrix.