Spectroscopic Study of Phytosynthesized Ag Nanoparticles and Their Activity as SERS Substrate

Abstract

The affordable and scalable synthesis of noble metal nanoparticles that are biocompatible without additional functionalization steps has been a growing field of research, stimulated by numerous prospective applications of these NPs. In the case of phytosynthesized or biogenic noble metal NPs, the mechanism of NP stabilization by biomolecules contained in each particular plant extract or living organism determines the possible applications of these NPs. In this work, we investigated Ag NPs synthesized in water with plant extracts of common toothwort (Lathraea squamaria) and two species of pepper (Capsicum annuum and Capsicum chinense). From FTIR and XPS, we drew conclusions about the composition of the functional groups and molecules that stabilize NPs in each extract, such as polysaccharide compounds (pectins, cellulose, glycosides and phenolic acids). Distinct characteristic IR features of amide I and amide II proteins were observed, which are common in plant extracts, while features of amide III were not distinctly observed in our extracts. A Raman spectroscopy study revealed weak own-SERS activity of the biomolecules of the extract and high efficiency of the NPs in the enhancement of “external” analytes, such as dyes and antibodies. This is the first report of the efficient SERS application of phytosynthesized Ag NPs.

ZnO and Ag NP-decorated ZnO nanoflowers: green synthesis using Ganoderma lucidum aqueous extract and characterization

“…The reduction of silver ions that leads to Ag NP formation on the surface of the ZnO flower-like NPs was attempted in the present work with different extracts, including G. lucidum mycoextract, but here we present only the results obtained with the chili pepper ( Capsicum annuum ) fruit extract. The latter has been recently demonstrated to mediate the formation of free-standing colloidal Ag NPs, 11,23 and that synthesis is shown here to be compatible with the G. lucidum mycoextract-mediated synthesis of ZnO NPs, producing ZnO/Ag heteroparticles. Fig.…”

“…ZnO, including ZnO nanoparticles and microstructures, has attracted the steady interest of researchers for decades. [1][2][3] The variety of its applications explains the need for different approaches to its synthesis [3][4][5][6][7][8][9][10][11] and the formation of its heterostructures with semiconductor or metal nanostructures. [4][5][6] Green chemistry approaches to nanoparticle (NP) production have the advantages of eco-friendly and hazard-free manufacturing, and economic and time-effective biosynthesis.…”

“…[4][5][6] Green chemistry approaches to nanoparticle (NP) production have the advantages of eco-friendly and hazard-free manufacturing, and economic and time-effective biosynthesis. [6][7][8][9][10][11][12] In their biosynthesis, NPs are coated with bioorganic molecules, which makes them more easily disposable and suitable for biomedical applications. While the most signicant previous work has been devoted to biosynthesized Ag NPs, 11,[13][14][15] recently there has been an increasing amount of work reporting the synthesis of ZnO NPs based on plant and fungi extracts 8,10,12,16 and their use for various biomedical applications and catalysis.…”

“…[6][7][8][9][10][11][12] In their biosynthesis, NPs are coated with bioorganic molecules, which makes them more easily disposable and suitable for biomedical applications. While the most signicant previous work has been devoted to biosynthesized Ag NPs, 11,[13][14][15] recently there has been an increasing amount of work reporting the synthesis of ZnO NPs based on plant and fungi extracts 8,10,12,16 and their use for various biomedical applications and catalysis. 10,12,17 An extension or enhancement of the applied functionality of ZnO nano-/ microstructures can be achieved by forming heterostructures with noble metal NPs.…”

Comparative assessment of the biological activity of the green synthesized silver nanoparticles and aqueous leaf extract of Perilla frutescens (L.)

“…It has been indicated that the spherical structure of AgNPs is a reason for creating unremarkable Raman peaks 20 . SERS spectroscopy has been rarely reported for biosynthesized AgNPs 19,45 . Indeed, the SERS experiments represented that the feature of (phyto)-functionalization of AgNPs permits other molecules to approach the NPs surface (a distance of a few nm) to "feel" the plasmon eld of the NPs and this information is very important for other applications of the biosynthesized NPs 45 .…”