Honey-Mediated CeO₂ Nanoparticles: A Cost-Effective Approach for Electrochemical Biosensing of Human Serum Albumin

Human serum albumin (HSA), the most abundant blood plasma protein, is a vital biomarker for diagnosing various health conditions. This study introduces a green and innovative approach for synthesizing CeO₂ nanoparticles (NPs) using natural honey as a reducing and stabilizing agent. Comprehensive spectroscopic characterization revealed that the synthesized CeO₂ NPs possess a spongy cobblestone morphology (∼13 nm) and an optical bandgap of 3.51 eV. Electrochemical properties were examined using cyclic voltammetry (CV), while UV-visible absorption spectroscopy and electrochemical analyses provided detailed insights into the nano-bio interactions between CeO₂ NPs and HSA, highlighting the kinetics of protein adsorption and the bioreactivity of the NPs. The optical binding interactions achieved a low limit of detection (LOD) of 3.42 nM, demonstrating exceptional sensitivity to HSA at trace concentrations. CeO₂ NPs were incorporated onto glassy carbon (GCE) and graphite electrodes to fabricate advanced biosensors. Both electrodes exhibited excellent selectivity, linear response ranges, and low detection limits of 2.09 nM (GCE) and 3.3 nM (graphite) for HSA detection. Interference studies confirmed minimal signal variation (±5%) in the presence of common interferents, demonstrating robust anti-interference capabilities. Notably, the CeO₂-modified graphite electrode offers a cost-effective alternative with performance comparable to that of the conventional GCE. Electrochemical sensing was further validated using authentic blood serum (BS) samples, confirming its reliability in real-world applications. The biosensor's repeatability, reproducibility, and long-term stability were also assessed, demonstrating consistent performance in biological matrices. Therefore, this work establishes CeO₂-modified electrodes as highly sensitive, selective, and economical platforms for real-time HSA detection. The findings hold significant promise for advancing biosensor technologies with broad applications in clinical diagnostics, environmental monitoring, and next-generation sensing systems.