Flower like Bi structures on Pt surface facilitating effective cholesterol biosensing

• Stable bismuth adlayers on Pt by electrochemical cycling
• Bi-Pt electrode showed excellent catalytic activity than Pt in neutral medium.
• Low overpotential H2O2 oxidation with high sensitivity
• Sensitive and interference free cholesterol detection feasible with H2O2 transduction

This work demonstrates effective biosensing of cholesterol with the help of an efficient inorganic H2O2 transducer based on Pt-Bi combined with the organic enzyme platform. It could be shown that the Bi (bismuth) adatoms modified Pt (platinum) surface displays enhanced catalytic oxidation of H2O2 at neutral pH and the catalytic oxidation of H2O2 occurs at a lower potential of 0.25 V vs NCE (normal calomel electrode). The sensing platform is highly sensitive and shows linear response towards [H2O2] in the absence of any redox mediator or enzyme. The H2O2 sensing platform, further modified with cholesterol oxidase led to cholesterol biosensing with a sensitivity of 3.41 μA mM− 1 cm− 2. The apparent Michaelis-Menten constant (Kmapp) was calculated to be 0.43 mM which indicates high binding affinity with the substrate. The cholesterol biosensor does not suffer from the interferences due to other common electroactive species and is highly stable.

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