Molecularly-imprinted polymer based on graphene oxide functionalized pencil graphite electrode for cholesterol detection

Cholesterol plays a vital role in biological functions that must be maintained at a normal level of < 5.2 mmol/L to prevent hypercholesterolemia, leading to cardiovascular diseases. This research examines a molecularly-imprinted polymer (MIP) based biosensor using a pencil graphite electrode (PGE) modified graphene oxide (GO) for the sensitive, selective, and stable detection of cholesterol with a simple approach using the electropolymerization process. The imprinted poly[2-(dimethylamino) ethyl methacrylate] (poly[DMAEMA]) layers on PGE/GO surface exhibit strong electrochemical responses during cholesterol detection through the formation of cholesterol-specific recognition cavities that were formed to mimic the cholesterol's structures, allowing non-enzymatic detection. Through the optimization of the parameters during electropolymerization, including the ratio of template molecule concentration to monomer, polymerization and template removal cycles, scan rate, rebinding duration, and pH, the sensor demonstrated satisfactory performance. With the limit of detection (LOD) of 0.85 mM, limit of quantification (LOQ) of 2.85 mM, a linear range of 1–6 mM, and sensitivity of 40.52 μA.μM⁻¹ .cm⁻², the sensor offered good electrochemical performance and selectivity towards cholesterol, despite the presence of other interference molecules. The current stability percentage on the tenth day was 85.52 %, which indicates good stability of the sensor modification and indicates potential for repeated cholesterol sensing for further point-of-care testing (POCT) application.