Label-free electrochemical immunosensor as a reliable point-of-care device for the detection of Interleukin-6 in serum samples from patients with psoriasis

Abstract

Interleukin-6 (IL-6) plays a crucial role in autoimmunity and chronic inflammation. This study aims to develop a low-cost, simple-to-manufacture, and user-friendly label-free electrochemical point-of-care device for the rapid detection of IL-6 in patients with psoriasis. Precisely, a sandwich-based format immunosensor was developed using two primary antibodies (mAb-IL6 clone-5 and clone-7) and screen-printed electrodes modified with an inexpensive recycling electrochemical enhancing material, called biochar. mAb-IL6 clone-5 was used as a covalently immobilized capture bioreceptor on modified electrodes, and mAb-IL6 clone-7 was used to recognize the immunocomplex (Anti-IL6 clone-5 and IL-6) and form the sandwich. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to conduct electrochemical characterization of the layer-by-layer assembly of the immunosensor, while square wave voltammetry (SWV) was used to perform the sensing. The developed immunosensor demonstrated robust analytical performance in buffer solution, with a wide linear range (LR) by varying from 2 to 250 pg/mL, a good limit of detection (LOD) of 0.78 pg/mL and reproducibility (RSD<7%). In addition, a spectrophotometric ELISA kit was employed to validate the results obtained with the label-free device by analyzing twenty-five serum samples from control and patients affected by psoriasis. A strong correlation in terms of pg/mL concentration of IL-6 was found comparing the two methods, with the advantage for our label-free biosensor of an ease use and a quicker detection time. Based on IL-6 levels, the proposed immunosensor is a dependable, non-invasive screening device capable of predicting disease onset, progression, and treatment efficacy.

An ethyl cellulose novel biodegradable flexible substrate material for sustainable screen-printing

“…This is conrmed by DE values, which are always higher than 59 mV, thus suggesting a sluggish electron exchange. 35 This criterion is crucial for recognising Nernstian behaviour and calculating the number of electrons transferred. All platforms in this instance can be classied as a "quasi-reversible" system.…”

Impact of Blood-Count-Derived Inflammatory Markers in Psoriatic Disease Progression

“…Moreover, despite the rapidly growing knowledge regarding cytokines and interleukins' involvement in psoriasis, they prove to be expensive and scarcely available to routinely assess inflammatory state in psoriasis. A clear-cut and prompt analysis of interleukin levels might be offered in the future by validated novel point-of-care devices using label-free electrochemical immunosensors, such as one determining IL-6 levels [10]. As such, a proper identification and comprehensive analysis of simple, low-cost, and widely available markers of systemic inflammation may provide much-needed additional data for a proper diagnosis, assessment, and treatment of patients with psoriasis.…”