A shell of nanostructured ferric tannates was spontaneously developed on the surface of naked maghemite nanoparticles (SAMNs, the core) by a simple wet reaction with tannic acid (TA). The as obtained core-shell nanomaterial (SAMN@TA) displays specific electrocatalytic and surface properties, which significantly differ from parent maghemite. Thanks to the known proclivity of TA to interact with proteins, SAMN@TA was proposed as a support for the direct immobilization of an enzyme. A ternary functional nanobioconjugate (SAMN@TA@TvL) was successfully self-assembled by incubating laccase from Trametes versicolor (TvL) and SAMN@TA. The SAMN@TA@TvL hybrid was kinetically characterized with respect to the native enzyme and applied for building an easy-to-use analytical device for the detection of polyphenols. The electrochemical biosensor allowed the determination of polyphenols by square wave voltammetry in mixed water-methanol solutions. The system sensitivity was 868.9 ± 1.9nA µM-1, the LOD was 81 nM and the linearity range was comprised between 100 nM and 10 µM. The proposed approach was successfully applied to detect phenolics in blueberry extracts as real samples. Results suggest that SAMN@TA could be a promising, low cost and versatile tool for the creation of nano-bio-conjugates aimed at the development of new electrochemical sensing platforms.

中文翻译：

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电催化纳米结构单宁酸铁作为酶结合的平台：酚类化合物的电化学测定。

通过与鞣酸（TA）的简单湿反应，在裸露的磁赤铁矿纳米颗粒（SAMNs，核）的表面上自然发展出了一种纳米结构的鞣酸铁壳。所获得的核-壳纳米材料（SAMN @ TA）具有特定的电催化和表面性质，与母磁赤铁矿显着不同。由于TA与蛋白质相互作用的可能性，SAMN @ TA被提议为直接固定酶的支持。通过温育Trametes versicolor（TvL）和SAMN @ TA的漆酶成功地自组装了三元功能纳米生物共轭物（SAMN @ TA @ TvL）。SAMN @ TA @ TvL杂种相对于天然酶具有动力学特性，可用于构建易于使用的检测多酚的分析装置。电化学生物传感器允许通过方波伏安法在水-甲醇混合溶液中测定多酚。系统灵敏度为868.9±1.9nA µM-1，LOD为81 nM，线性范围为100 nM至10 µM。所提出的方法已成功地应用于检测蓝莓提取物中的酚类物质（作为真实样品）。结果表明，SAMN @ TA可能是一种有前途，低成本且用途广泛的工具，可用于开发旨在开发新型电化学传感平台的纳米生物共轭物。所提出的方法已成功地应用于检测蓝莓提取物中的酚类物质（作为真实样品）。结果表明，SAMN @ TA可能是一种有前途，低成本且用途广泛的工具，可用于开发旨在开发新型电化学传感平台的纳米生物共轭物。所提出的方法已成功地应用于检测蓝莓提取物中的酚类物质（作为真实样品）。结果表明，SAMN @ TA可能是一种有前途，低成本且用途广泛的工具，可用于开发旨在开发新型电化学传感平台的纳米生物共轭物。