Adkins Jaley Faith, Kaur Amandeep, Alom Md Sofiul, Chandran Haridas, Ramezanipour Farshid, Wilson Andrew J
Department of Chemistry, University of Louisville Louisville Kentucky 40292 USA
Belfry High School Belfry Kentucky 41514 USA.
RSC Adv. 2023 Aug 23;13(36):25360-25368. doi: 10.1039/d3ra03847e. eCollection 2023 Aug 21.
Kudzu is an abundant and invasive species in the Southeastern United States. The prospective use of kudzu as a non-toxic, green and biocompatible reducing and stabilizing agent for one-pot Ag nanoparticle synthesis was investigated. Ag nanoparticles were synthesized using aqueous and ethanolic kudzu leaf and stem extracts. The size and dispersity of the synthesized nanoparticles were found to depend on the extract used. Ultraviolet-visible and Fourier transform infrared spectroscopies were used to characterize the extracts. Surface-enhanced fluorescence and Raman scattering were used to characterize the surface species on synthesized Ag nanoparticles. The primary reducing and stabilizing agents in aqueous kudzu leaf extracts were determined to be reducing sugars and saponins which result in Ag nanoparticles with average diameters of 21.2 ± 4.8 nm. Ethanolic kudzu leaf extract was determined to be composed of chlorophyll, reducing sugars and saponins, producing Ag nanoparticles with average diameters of 9.0 ± 1.6 nm. Control experiments using a chlorophyllin standard as the reducing and stabilizing agent reveal that chlorophyll has a key role in the formation of small and monodisperse Ag nanoparticles. Experiments carried out in the absence of light demonstrate that reducing sugars and saponins also contribute to the formation of Ag nanoparticles in ethanolic kudzu leaf extracts. We propose a mechanism by which reducing sugars donate electrons to reduce Ag leading to the formation of Ag nanoparticles, forming carboxylic acid sugars which stabilize and partially stabilize Ag nanoparticles synthesized with aqueous and ethanolic kudzu leaf extracts, respectively. In the ethanolic extract, photoexcited chlorophyll serves as a co-reducing and co-stabilizing agent, leading to small and monodisperse Ag nanoparticles.
葛根是美国东南部一种分布广泛的入侵物种。本文研究了葛根作为一种无毒、绿色且具有生物相容性的还原剂和稳定剂用于一锅法合成银纳米颗粒的潜在用途。使用葛根叶和茎的水提取物及乙醇提取物合成了银纳米颗粒。发现合成纳米颗粒的尺寸和分散性取决于所使用的提取物。采用紫外可见光谱和傅里叶变换红外光谱对提取物进行了表征。利用表面增强荧光和拉曼散射对合成银纳米颗粒表面的物种进行了表征。确定葛根叶水提取物中的主要还原剂和稳定剂为还原糖和皂苷，由此合成的银纳米颗粒平均直径为21.2±4.8 nm。葛根叶乙醇提取物由叶绿素、还原糖和皂苷组成，所制备的银纳米颗粒平均直径为9.0±1.6 nm。以叶绿酸标准品作为还原剂和稳定剂进行的对照实验表明，叶绿素在小尺寸且单分散的银纳米颗粒形成过程中起关键作用。在无光条件下进行的实验表明，还原糖和皂苷也有助于葛根叶乙醇提取物中银纳米颗粒的形成。我们提出了一种机制，即还原糖提供电子还原银从而导致银纳米颗粒的形成，形成的羧酸糖分别稳定了用葛根叶水提取物和乙醇提取物合成的银纳米颗粒。在乙醇提取物中，光激发的叶绿素作为共还原剂和共稳定剂，从而形成小尺寸且单分散的银纳米颗粒。
