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

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. SnO₂was synthesized via the hydrothermal method, followed by the synthesis of SnO₂-PANI nanocomposite throughin situchemical 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 1-100μM with a sensitivity of 300μAμM^-1/cm^-2towards CH sensing and a low limit of detection of 0.25μM (=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.

Keywords: SnO2-PANI; cholesterol; electrochemical sensor; hydrothermal synthesis; non-enzymatic sensor.