Biogenic silver nanoparticles: New trends and applications

Synthesis characterization and application of butyl acrylate mediated eco-friendly silver nanoparticles using ultrasonic radiation

In the present investigation, with an effort to provide appropriate material for future applications, we have touched on two viable advancement targets: the production of silver nanoparticles (Ag-NPs) employing an ultrasonic approach and the use of Ag-NPs in environmental remediation. A green economical method was involved to prepare Ag-NPs using butyl acrylate as a stabilizer. The following techniques were used for analysing Ag-NPs: energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), powder X-ray diffraction (XRD), and Fourier transformed infrared (FT-IR) spectroscopy. X-ray diffraction (XRD) analysis for the lattice characteristics showed that Ag-NPs have a face-centered structure with an average crystallite size of 9.51-11.83 nm. FE-SEM and TEM analysis were used for morphological investigations, and revealed that Ag-NPs had a spherical shape with an average particle size of 16.27 nm. The EDX profile displayed a strong signal at ∼3.0 keV, which indicated that the samples comprised silver. UV-Visible spectrophotometer with the absorption maximum occurring between 401 and 411 nm further confirmed the formation of Ag-NPs. The dye degradation effect of synthesized Ag-NPs on methylene blue and Rhodamine B was analyzed to assess their ability for environmental remediation, and results showed that around 100% of the dye degradation effect. This study has provided a most plausible mechanism for the dye degradation.

Effect of Bacterial Cellulose Plasma Treatment on the Biological Activity of Ag Nanoparticles Deposited Using Magnetron Deposition

New functional medical materials with antibacterial activity based on biocompatible bacterial cellulose (BC) and Ag nanoparticles (Ag NPs) were obtained. Bacterial cellulose films were prepared by stationary liquid-phase cultivation of the Gluconacetobacter hansenii strain GH-1/2008 in Hestrin-Schramm medium with glucose as a carbon source. To functionalize the surface and immobilize Ag NPs deposited by magnetron sputtering, BC films were treated with low-pressure oxygen-nitrogen plasma. The composition and structure of the nanomaterials were studied using transmission (TEM) and scanning (SEM) electron microscopy and X-ray photoelectron spectroscopy (XPS). Using electron microscopy, it was shown that on the surface of the fibrils that make up the network of bacterial cellulose, Ag particles are stabilized in the form of aggregates 5-35 nm in size. The XPS C 1s spectra show that after the deposition of Ag NPs, the relative intensities of the C-OH and O-C-O bonds are significantly reduced. This may indicate the destruction of BC oxypyran rings and the oxidation of alcohol groups. In the Ag 3d_5/2 spectrum, two states at 368.4 and 369.7 eV with relative intensities of 0.86 and 0.14 are distinguished, which are assigned to Ag⁰ state and Ag acetate, respectively. Nanocomposites based on plasma-treated BC and Ag nanoparticles deposited by magnetron sputtering (BCP-Ag) exhibited antimicrobial activity against Aspergillus niger, S. aureus and Bacillus subtilis.