Cerium-Modulated Zinc Oxide for enhanced Photoelectrochemical Non-Enzymatic biosensing of Cholesterol: An experimental and First Principle Analysis

Abstract

Herein, we synthesized Ce<inf>x</inf>Zn<inf>1-x</inf>O (x = 0.00, 0.01, 0.02, and 0.03) using the wet chemical method. The investigation explores photoelectrochemical (PEC) biosensors for enzyme-free detection of cholesterol, employing Ce<inf>0.03</inf>Zn<inf>0.97</inf>O (CZO3)/Nickel Foam (NF) as the active material. The investigation revealed notable enhancements in sensitivity for cholesterol detection, with a recorded activity of 2.812 mA.mM?1.cm?2, marking a twofold increase in comparison to dark mode (1.37 mA.mM?1.cm?2). The Limit of Detection (LOD) was determined to be 17 µM (light) and 28 µM (dark), while the Limit of Quantification (LOQ) was measured at 54 µM (light) and 98 µM (dark) in 0.1 M KOH solution. These findings demonstrate a linear detection range spanning from 80 µM to 2 mM. Ab-initio calculations based on Density Functional Theory (DFT) were carried out on 101 surfaces of both pristine ZnO and CZO3 to understand how the doping affected the pristine ZnO band gap. The findings indicate that CZO3 exhibits superior activity compared to pristine ZnO, underscoring its enhanced performance and potential for sensing application. The CZO3/NF photoelectrochemical (PEC) biosensor displayed notable cyclic stability, retaining 97 % of its performance over a 60-day period. This underscores its potential for reliable and enduring operation in biosensing applications. Additionally, CZO3/NF exhibited robust sensing capabilities when utilized with human serum samples, showcasing consistent performance in both dark and illuminated conditions. © 2024 Elsevier B.V.