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

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 (SnO -PANI/NF) for non-enzymatic detection of CH in simulated human blood serum. SnO was synthesized via the hydrothermal method, followed by the synthesis of SnO -PANI nanocomposite through chemical polymerization of aniline using ammonium persulfate as the oxidizing agent. Morphological studies display agglomerated SnO -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 SnO -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 SnO -PANI/NF sensor exhibits a linear range of 1-100 M with a sensitivity of 300 A M /cm towards CH sensing and a low limit of detection of 0.25 M (=3 S m ). SnO -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 SnO -PANI/NF sensor demonstrated excellent selectivity against interfering species such as Na , Cl , K , glucose, ascorbic acid, and SO . The sensor successfully determined the concentration of CH in simulated blood serum samples, demonstrating SnO -PANI as a potential platform for a variety of electrochemical-based bioanalytical applications.