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. SnOwas synthesized via the hydrothermal method, followed by the synthesis of SnO-PANI nanocomposite throughchemical 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 1-100M with a sensitivity of 300AM/cmtowards CH sensing and a low limit of detection of 0.25M (=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.