Development of a Sensitive Electrochemical Enzymatic Reaction-Based Cholesterol Biosensor Using Nano-Sized Carbon Interdigitated Electrodes Decorated with Gold Nanoparticles

Abstract

We developed a versatile and highly sensitive biosensor platform. The platform is based on electrochemical-enzymatic redox cycling induced by selective enzyme immobilization on nano-sized carbon interdigitated electrodes (IDEs) decorated with gold nanoparticles (AuNPs). Without resorting to sophisticated nanofabrication technologies, we used batch wafer-level carbon microelectromechanical systems (C-MEMS) processes to fabricate 3D carbon IDEs reproducibly, simply, and cost effectively. In addition, AuNPs were selectively electrodeposited on specific carbon nanoelectrodes; the high surface-to-volume ratio and fast electron transfer ability of AuNPs enhanced the electrochemical signal across these carbon IDEs. Gold nanoparticle characteristics such as size and morphology were reproducibly controlled by modulating the step-potential and time period in the electrodeposition processes. To detect cholesterol selectively using AuNP/carbon IDEs, cholesterol oxidase (ChOx) was selectively immobilized via the electrochemical reduction of the diazonium cation. The sensitivity of the AuNP/carbon IDE-based biosensor was ensured by efficient amplification of the redox mediators, ferricyanide and ferrocyanide, between selectively immobilized enzyme sites and both of the combs of AuNP/carbon IDEs. The presented AuNP/carbon IDE-based cholesterol biosensor exhibited a wide sensing range (0.005–10 mM) and high sensitivity (~993.91 µA mM−1 cm−2; limit of detection (LOD) ~1.28 µM). In addition, the proposed cholesterol biosensor was found to be highly selective for the cholesterol detection.

An Electrochemical Cholesterol Biosensor Based on A CdTe/CdSe/ZnSe Quantum Dots—Poly (Propylene Imine) Dendrimer Nanocomposite Immobilisation Layer

“…Most food such as fatty red meat, eggs, cream, burgers, and animal fats contain high levels of cholesterol, which can lead to increase in the blood cholesterol level when consumed [ 3 , 4 , 5 ]. As important as cholesterol is for the body, it may cause health problems when it exists at a concentration higher than 5.2 mM (200 mg·dL −1 ) [ 5 , 6 , 7 , 8 ]. A high level of cholesterol can cause atherosclerosis, which is the hardening and narrowing of the heart arteries leading to an increased risk of cardiovascular diseases (CVDs) such as hypertension, stroke and heart attack [ 9 , 10 , 11 ].…”

“…Therefore, early detection, prevention and effective management of cholesterol level are of importance to human health and in diagnosis. Techniques such as high-pressure liquid chromatography (HPLC), mass spectroscopy, calorimetry, spectrophotometry, fluorimetry, electrochemistry and polarography have been used to analyze cholesterols and many other small biomolecules [ 7 , 13 , 14 , 15 , 16 , 17 ]. Among these methods, electrochemical detection methods, which include biosensors, have shown high potential owing to their high sensitivity, specificity and stability, rapid response time, cost-effectiveness, use of small sample volumes, miniaturisability and their good compatibility with advanced micromachining technologies [ 16 , 18 , 19 , 20 , 21 ].…”

Metal Nanoparticles Based Electrochemical Biosensors for Cholesterol

“…The specific molecular recognition of CHO upto nanolevel by digitonin gold nanoparticles was reported [4]. Electrochemical-enzymatic sensor by selective enzyme immobilization on nano-sized carbon interdigitated electrodes decorated with gold nanoparticles claim CHO estimation with LOD 1.28 μM [5]. Pt-Bi combined with the organic enzyme platform, demonstrates effective μM biosensing of CHO [6].…”

Glassy Carbon: A Promising Material for Micro- and Nanomanufacturing

“…Selected examples of glassy carbon electrode modification via decoration with other materials are listed in Table 4 . The modifying agents are divided into four categories for convenience, and only five examples from each are provided, since the idea here is to present surface modification as a possibility for further sensitivity improvement of miniaturized glassy carbon devices (one such example [ 107 ] is listed in Table 2 ). Notably, in the case of multilayer or composite material coatings, the exact mechanism of the electrocatalytic activity as well as the contribution from glassy carbon itself is occasionally not completely understood.…”