A novel and sensitive electrochemical cholesterol biosensor was developed based on immobilization cholesterol oxidase (ChOx) on the polyaniline/crystalline nanocellulose/ionic liquid modified Screen-Printed Electrode (PANi/CNC/IL/SPE). A thin layer of ionic liquid (IL) was spin coated on the modified electrode to enhance the electron transferring. Crystalline nanocellulose was prepared from Semantan bamboo (Gigantochloa scortechinii) via acid hydrolysis and it was used to synthesize a nanocomposite of PANi/CNC via in situ oxidative polymerization process. FESEM and TEM images showed high porosity of the nanostructure with no phase separation, revealing the homogenous polymerization of the monomer on the surface of the crystalline cellulose. Research surface methodology (RSM) was carried out to optimize the parameters and conditions leading to maximize the performance and sensitivity of biosensors. The PANi/CNC/IL/GLU/ChOx-modified electrode showed a high sensitivity value of 35.19 μA mM/cm-2 at optimized conditions. The proposed biosensor exhibited a dynamic linear range of 1 μM to 12 mM (R2 = 0.99083) with the low Limit of Detection of 0.48 μM for cholesterol determination. An acceptable reproducibility (RSDs ≤3.76%) and repeatability (RSDs ≤3.31%) with the minimal interference from the coexisting electroactive compounds such as ascorbic acid, uric acid and glucose was observed for proposed biosensor.
Keywords: Biosensor; Cholesterol oxidase; Crystalline nanocellulose; Ionic liquid; Polyaniline; RSM.
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