Abstract This work describes the preparation of an electrochemical biosensor for polyphenols determination in propolis samples. The biosensing scheme is based on a nanocomposite film of laccase enzyme (Lac) immobilized on gold nanoparticles (AuNPs) electrodeposited in a screen-printed carbon electrode (SPCE) modified with polypyrrole (Ppy) through an in-situ electropolymerization. The electrodeposition of the AuNPs increases the available area for Lac immobilization. The nanocomposite film (Ppy/Lac/AuNPs/SPCE) was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and cyclic voltammetry. Polyphenols were detected in ethanolic extracts of propolis (EEP), where in presence of the Lac oxidized to the polyphenols, and so they can be reduced on the Ppy/Lac/AuNPs/SPCE by amperometry at −450 mV vs Ag/AgCl. The calibration plot showed a linear response in the concentration range from 1 to 250 μM expressed as caffeic acid, with a limit of detection of 0.83 μM. The time required for analysis was 15 min, compared to the time (85 min) by spectrophotometric methods, especially the so-called Folin-Ciocalteu method. The method exhibited good selectivity, stability and reproducibility for detecting polyphenols in propolis samples.

中文翻译：

---

基于固定在纳米结构丝网印刷电极上的漆酶的电流型生物传感器用于测定蜂胶中的多酚

摘要 这项工作描述了用于测定蜂胶样品中多酚的电化学生物传感器的制备。生物传感方案基于固定在金纳米粒子 (AuNPs) 上的漆酶 (Lac) 纳米复合膜，通过原位电聚合电沉积在用聚吡咯 (Ppy) 修饰的丝网印刷碳电极 (SPCE) 中。AuNPs 的电沉积增加了 Lac 固定的可用面积。通过扫描电子显微镜、能量色散 X 射线光谱和循环伏安法对纳米复合薄膜 (Ppy/Lac/AuNPs/SPCE) 进行表征。在蜂胶 (EEP) 的乙醇提取物中检测到多酚，其中存在 Lac 被氧化成多酚，因此它们可以在 Ppy/Lac/AuNPs/SPCE 上通过 -450 mV 与 Ag/AgCl 的电流分析法被还原。校准图在 1 到 250 μM 的浓度范围内显示线性响应，以咖啡酸表示，检测限为 0.83 μM。与分光光度法，尤其是所谓的 Folin-Ciocalteu 方法的时间（85 分钟）相比，分析所需的时间为 15 分钟。该方法在检测蜂胶样品中的多酚方面表现出良好的选择性、稳定性和重现性。