Abstract A simple, eco-friendly, cost-effective and rapid microwave-assisted method has been developed to synthetize dendritic silver nanostructures, composed of silver nanoparticles (AgNPs), using white grape pomace aqueous extract (WGPE) as both reducing and capping agent. With this aim, WGPE and AgNO3 (1 mM) were mixed at different ratio, and microwave irradiated at 700 W, for 40 s. To understand the role of bioactive compounds involved in the green synthesis of AgNPs, preliminary chemical characterization, FT-IR analysis and 1H NMR metabolite profiling of WGPE were carried out. The effects of bioactive extract concentration and stability over time on AgNPs formation were also evaluated. WGPE-mediated silver nanostructures were then characterized by UV–vis, FTIR analyses, and scanning electron microscopy. Interestingly, the formation of dendritic nanostructures, originated from the self-assembly of Ag rounded nanoparticles (average diameter of 33 ± 6 nm), was observed and ascribed to the use of microwave power and the presence of organic components within the used WGPE, inducing an anisotropic crystal growth and promoting a diffusion-limited aggregation mechanism. The bio-dendritic synthetized nanostructures were also evaluated for potential applications in bio-sensing and agricultural fields. Cyclic voltammetry measurements in 0.5 M phosphate + 0.1 M KCl buffer, pH 7.4 showed that green AgNPs possess the electroactive properties typical of AgNPs produced using chemical protocol. The biological activity of synthetized AgNPs was evaluated by in-vitro antifungal activity against F. graminearum. Additionally, a phytotoxicity evaluation of synthetized green nanostructures was carried out on wheat seed germination. Results highlighted the potential of WGPE as green agent for bio-inspired nanomaterial synthesis, and of green Ag nanostructures, which can be used as antifungal agent and in biosensing applications.

中文翻译：

---

从白葡萄渣开始合成树枝状银纳米结构的完全绿色方法作为潜在的纳米工厂

摘要 以白葡萄果渣水提物 (WGPE) 作为还原剂和封端剂，开发了一种简单、环保、经济且快速的微波辅助方法来合成由银纳米粒子 (AgNPs) 组成的树枝状银纳米结构。为此，WGPE 和 AgNO3 (1 mM) 以不同的比例混合，并以 700 W 的微波辐射 40 秒。为了了解生物活性化合物在 AgNPs 绿色合成中的作用，进行了 WGPE 的初步化学表征、FT-IR 分析和 1H NMR 代谢物分析。还评估了生物活性提取物浓度和稳定性对 AgNPs 形成的影响。然后通过 UV-vis、FTIR 分析和扫描电子显微镜对 WGPE 介导的银纳米结构进行表征。有趣的是，观察到树枝状纳米结构的形成源于 Ag 圆形纳米粒子（平均直径为 33 ± 6 nm）的自组装，并将其归因于微波功率的使用和所用 WGPE 中有机成分的存在，诱导各向异性晶体生长并促进扩散限制聚集机制。还评估了生物树枝状合成纳米结构在生物传感和农业领域的潜在应用。在 0.5 M 磷酸盐 + 0.1 M KCl 缓冲液，pH 7.4 中的循环伏安测量表明，绿色 AgNPs 具有使用化学协议生产的 AgNPs 的典型电活性特性。通过对禾谷镰刀菌的体外抗真菌活性评估合成的 AgNPs 的生物活性。此外，对合成的绿色纳米结构的植物毒性进行了对小麦种子萌发的评估。结果突显了 WGPE 作为仿生纳米材料合成绿色试剂的潜力，以及可用作抗真菌剂和生物传感应用的绿色银纳米结构的潜力。