Tin oxide-polyaniline nanocomposite modified nickel foam for highly selective and sensitive detection of cholesterol in simulated blood serum samples

Abstract

Abstract Cholesterol (CH) is a vital diagnostic marker for a variety of diseases, making its detection crucial in biological applications including clinical practice. In this work, we report the synthesis of tin oxide-polyaniline nanocomposite-modified nickel foam (SnO2-PANI/NF) for non-enzymatic detection of CH in simulated human blood serum. SnO2 was synthesized via the hydrothermal method, followed by the synthesis of SnO2-PANI nanocomposite through in situ chemical polymerization of aniline using ammonium persulfate as the oxidizing agent. Morphological studies display agglomerated SnO2-PANI, which possess diameters ranging from an average particle size of ∼50 to ∼500 nm, and the XRD analysis revealed the tetragonal structure of the SnO2-PANI nanocomposite. Optimization studies demonstrating the effect of pH and weight percentage are performed to improve the electrocatalytic performance of the sensor. The non-enzymatic SnO2-PANI/NF sensor exhibits a linear range of 1–100 μM with a sensitivity of 300 μA μM−1/cm−2 towards CH sensing and a low limit of detection of 0.25 μM (=3 S m−1). SnO2-PANI/NF facilitates the electrooxidation of CH to form cholestenone by accepting electrons generated during the reaction and transferring them to the nickel foam electrode via Fe (III)/Fe (IV) conversion, resulting in an increased electrochemical current response. The SnO2-PANI/NF sensor demonstrated excellent selectivity against interfering species such as Na+, Cl−, K+, glucose, ascorbic acid, and SO4 2−. The sensor successfully determined the concentration of CH in simulated blood serum samples, demonstrating SnO2-PANI as a potential platform for a variety of electrochemical-based bioanalytical applications.