An Electrochemical Biosensor Based on Nanomaterials, MOF, and Laccase for Ultra-Sensitive Quantitative Detection of Luteolin

Luteolin (Lut) is a natural flavonoid with anti-inflammatory, antioxidant, and anti-tumor potential. Its dietary intake is associated with health risks, and developing highly selective detection methods is of great significance. In order to address the issue of poor selectivity of existing Lut sensors, this study constructed an electrochemical biosensor. The sensor was fabricated by modifying a glassy carbon electrode (GCE) with MWCNTs, UiO-66-NH₂ (MOF), AuNPs and laccase (Lac). By taking advantage of the high conductivity of multi-walled carbon nanotubes, the large specific surface area and enrichment effect of UiO-66-NH₂, the biocompatibility and electron transfer ability of AuNPs, as well as the biological catalytic specificity of Lac, significant performance synergy was achieved. The catalytic activity of Lac on Lut was studied by UV–vis, and the materials were characterized by electron microscopy, Fourier-transform infrared, and X-ray methods, respectively. The square wave voltammetry study demonstrated that this electrochemical sensor exhibited an excellent detection performance for Lut, with a linear detection range of 0.02–10 μM and a detection limit as low as 7.59 nM. In the actual samples (thyme, parsley, oregano) tests, the results were highly consistent with HPLC. The recovery rates after adding standards were ideal, fully demonstrating the excellent practical application potential.