Electrochemistry of cholesterol biosensor based on a novel Pt–Pd bimetallic nanoparticle decorated graphene catalyst

• Published in: Talanta (Oxford) Vol. 109; pp. 167 - 172
• Main Authors: Cao, Shurui, Zhang, Lei, Chai, Yaqin, Yuan, Ruo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-05-2013
• Subjects: Biosensing Techniques - instrumentation; Biosensing Techniques - methods; biosensors; Catalysis; catalysts; Chitosan - chemistry; cholesterol; Cholesterol - analysis; Cholesterol biosensor; Cholesterol oxidase (ChOx); Cholesterol Oxidase - chemistry; detection limit; Direct electrochemistry; Electrochemical Techniques - instrumentation; Electrochemical Techniques - methods; electrochemistry; Electrodes; electron transfer; enzyme kinetics; Enzymes, Immobilized - chemistry; Food Analysis; glassy carbon electrode; glucose; graphene; Graphene sheets (GS); Graphite - chemistry; Hybrid nanocomposites; Limit of Detection; Metal Nanoparticles - chemistry; Microscopy, Electron, Scanning; nanocomposites; nanoparticles; Palladium - chemistry; Platinum - chemistry; Pt–Pd; Reproducibility of Results; scanning electron microscopy; Surface Properties; Graphene sheets (GS); Hybrid nanocomposites; Cholesterol oxidase (ChOx); Direct electrochemistry; Cholesterol biosensor; Pt–Pd
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2013.02.002

A new electrochemical biosensor with enhanced sensitivity was developed for detection of cholesterol by using platinum–palladium–chitosan–graphene hybrid nanocomposites (PtPd–CS–GS) functionalized glassy carbon electrode (GCE). An electrodeposition method was applied to form PtPd nanoparticles-doped chitosan–graphene hybrid nanocomposites (PtPd–CS–GS), which were characterized by scanning electron microscopy (SEM) and electrochemical methods. The presence of the PtPd–CS–GS nanocomposites not only accelerated direct electron transfer from the redox enzyme to the electrode surface, but also enhanced the immobilized amount of cholesterol oxidase (ChOx). Under optimal conditions, the fabricated biosensor exhibited wide linear ranges of responses to cholesterol in the concentration ranges of 2.2×10−6 to 5.2×10−4M, the limit of detection was 0.75μM (S/N=3). The response time was less than 7s and the Michaelis–Menten constant (Kmapp) was found as 0.11mM. In addition, the biosensor also exhibited excellent reproducibility and stability. Along with these attractive features, the biosensor also displayed very high specificity to cholesterol with complete elimination of interference from UA, AA, and glucose.
► A new biosensor with enhanced sensitivity was developed for detection of cholesterol. ► Using Pt–Pd–CS–GS hybrid nanocomposites functionalized glassy carbon electrode. ► Accelerated direct electron transfer from the redox enzyme to the electrode surface. ► Reveal the specific cholesterol catalytic activity of the biosensor.