UiO-66/graphene quantum dot-based conductive nanohybrid ink for flexible PET-supported non-enzymatic electrochemical cholesterol sensing
Diamond and Related Materials, vol.169, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 169
- Publication Date: 2026
- Doi Number: 10.1016/j.diamond.2026.114096
- Journal Name: Diamond and Related Materials
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Keywords: Cholesterol, Conductive ink, Flexible electrode, Graphene quantum dots, UiO-66
- Yıldız Technical University Affiliated: Yes
Abstract
In this study, a flexible printed electrochemical sensor was developed for the enzyme-free determination of cholesterol (Chol) using a UiO-66/Graphene Quantum Dots/Graphite (UiO-66/GQD/G)-based conductive nanohybrid ink. The UiO-66/GQD/G ink was directly printed onto a polyethylene terephthalate (PET) substrate. The incorporation of porous UiO-66 metal-organic frameworks with conductive GQDs yielded a synergistic structure that combined abundant, readily accessible active sites with improved charge-transfer capability, thereby enhancing the electrochemical oxidation response of Chol. The performance of the fabricated electrodes was systematically investigated through environmental scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Under optimized experimental conditions, the UiO-66/GQD/G/SPE exhibited a wide linear response range from 1.0 to 500 μM and a low limit of detection of 0.319 μM for Chol detection. The sensor also demonstrated good selectivity against common interfering species and acceptable reproducibility, confirming the reliability of the printed nanohybrid electrode interface. In addition, the practical applicability of the proposed sensor was evaluated in artificial blood sample, yielding recovery values ranging from 98.33 to 109.50% and relative standard deviations between 2.58 and 3.64%. These findings indicate that the UiO-66/GQD/G conductive nanohybrid ink provides a practical, scalable, and low-cost platform for the fabrication of flexible PET-supported electrochemical sensors, offering a promising enzyme-free strategy for Chol monitoring.