PVIM–Co5POM/MNC composite as a flexible electrode for the ultrasensitive and highly selective non-enzymatic electrochemical detection of cholesterol

Abstract

To address the issues allied with cardiovascular diseases and the increased prevalence of hypertension, a novel electrochemical sensor was developed based on poly(ionic liquid) [PVIM]–cobalt polyoxometalate (Co₅POM) supported on carbonaceous materials (MNCs) for the highly selective and ultrasensitive non-enzymatic detection of cholesterol. The novel composite exhibits excellent selectivity and sensitivity towards the non-enzymatic electrochemical detection of cholesterol with a low detection limit of 1 fM (1 × 10⁻¹⁵ M), a response time of ∼5 s, and a wide detection range of 1 fM–5 mM with two linear ranges of 1 fM–200 nM and 0.5 μM–5 mM with sensitivities of 210 and 64 μA μM⁻¹ cm⁻², respectively, even in the presence of ascorbic acid, glucose and uric acid. The proposed sensor was tested with a human blood serum sample at physiological pH in a physiologically relevant concentration range. A novel flexible sensor was developed with PVIM–Co₅POM/MNC coated over Whatman filter paper and this shows a high sensitivity with a wide detection range of 1 fM–5 mM.