A Flexible Label-Free Biosensor Sensitive and Selective to TNF-a: Application for Chronic Heart Failure

Abstract

Tumor necrosis factor-a (TNF-a) is a key pro-inflammatory cytokine that is characterized by elevated circulating levels for chronic heart failure (CHF) and left ventricular assisted device (LVAD) implantation patients, respectively. Therefore, a rapid and ease-of-use diagnostic tool is required to monitor LVAD patients at a high risk of mortality during early expression of an inflammatory storm. In this paper, we report on the quantitative electrochemical detection of human TNF-a with its corresponding antibody (Ab) immobilized onto the functionalized biosensor surface. The label-free biosensor was fabricated on a gold surface that was deposited on a flexible polyimide (PI) substrate. The interfacial properties of the functionalized flexible gold electrodes were evaluated by cyclic voltammetry (CV) in the presence of Fe(CN)64-/3- as the redox-active species. Afterwards, the electrochemical impedance spectroscopy (EIS) technique was used to determine the TNF-a) concentrations. EIS results confirmed that the developed flexible biosensor can accurately detect TNF-a with a good sensitivity in the dynamic range of 0.1 pg/mL to 0.5 ng/mL. Overall, the developed flexible biosensor was easy to fabricate and the results demonstrate a good selectivity in the presence of other cytokines such as interleukin: (IL-10) and (IL-1).

Keywords

• Tumor necrosis factor-a)
• Flexible gold electrodes
• Electrochemical impedance spectroscopy.