Pd/C-decorated SnO2 for advanced non-enzymatic cholesterol biosensing: analytical application in clinical blood specimens

Abstract

Cholesterol, a critical biomolecule, plays a vital role in physiological functions; however, elevated levels are associated with chronic conditions such as cardiovascular diseases, which remain a leading cause of mortality globally. To address this challenge, this study presents the synthesis of SnO<inf>2</inf>-Pd/C nanocomposite through a two-step process as a promising material for non-enzymatic cholesterol biosensing. Initially, SnO<inf>2</inf> was synthesized via a hydrothermal method and subsequently decorated with Pd/C. The resulting SnO<inf>2</inf>-Pd/C nanocomposite was integrated with nickel foam (NF) as the active material for biosensor development. The biosensor demonstrated a remarkable sensitivity of 1560 µA mM?1 cm?2 for cholesterol detection, which is approximately three times higher than that of SnO<inf>2</inf>-NF (546 µA mM?1 cm?2). Key performance metrics included a Limit of Detection (LOD) of 28 µM and a Limit of Quantification (LOQ) of 34 µM in 0.1 M KOH solution, with a linear detection range extending from 200 µM to 2 mM. The SnO<inf>2</inf>-Pd/C-NF biosensor exhibited outstanding cyclic stability, retaining 97 % of its performance over 30 days, underscoring its potential for reliable and long-term applications. Furthermore, the sensor demonstrated robust and consistent sensing performance with human serum samples under standard conditions, highlighting its practical applicability in clinical diagnostics. © 2025 Elsevier B.V.