In this report, the metal-vapor synthesis (MVS) was used for the preparation of copper nanoparticles which was then used for the preparation of chitosan-copper nanocomposite. The antifungal activity of Cu@Chit NCs against two sclerotium-forming plant pathogenic fungi Sclerotium rolfsii (S. rolfsii) and Rhizoctonia solani (R. solani) AG-4 was evaluated in vitro and their effects on hyphal morphology, and sclerotia formation were observed for the first time. The NCs were prepared through impregnation of chitosan with colloid solution of copper nanoparticles in organic solvent (acetone or toluene). Transmission electron microscopy shows that the particles have predominantly spherical form, polydisperse character, the mean diameter about 2-3 nm and a rather uniform distribution in the chitosan matrice. Analysis of the small angle scattering curves suggests that the copper particles in the NCs with the size of B2 nm are mostly located in the chitosan pores with the same size. The effect of Cu@Chit NCs on fungal growth reveals some significant inhibitory activity against two tested fungi. The highest level of inhibition against S. rolfsii and R. solani AG-4 was observed using the high concentrations of Cu@Chit NC prepared using acetone as a solvent. A loss of the cytoplasm content, cytoplasmic coagulation, irregular shape of mycelia, or destruction in the hyphae was confirmed. The experiments demonstrate that the Cu@Chit NC synthesized via MVS using acetone was more effective than that of toluene in inhibiting fungal hyphae growth against R. solani AG-4 and S. rolfsii. The results show that the Cu@Chit NCs are fungicidal against both the tested fungus at high concentrations and the fungicidal or fungistatic activity is dependent on the tested fungus species.

A highly efficient solvent‐free protocol for the Buchwald–Hartwig (hetero)arylation of anilines, diarylamines, and dialkylamines mediated by the expanded‐ring N‐heterocyclic carbene palladium complex (THP‐Dipp)Pd(cinn)Cl [THP‐Dipp = 1,3‐bis(2,6‐diisopropylphenyl)‐3,4,5,6‐tetrahydropyrimidin‐2‐ylidene; cinn = cinnamyl, 3‐phenylallyl] was developed. The catalytic protocol was efficient for the coupling of amines and (hetero)aryl chlorides and bromides bearing donor, acceptor, and bulky substituents.

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Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method-the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains.

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In this work, the preparation and characterization of a novel multifunctional collagen–chitosan material containing silver nanoparticles and nonsteroid anti‐inflammatory drug ibuprofen is described. As a starting material, the commercially available collagen–chitosan scaffold was used. Drug‐loading procedure was performed via supercritical CO2‐assisted impregnation technique. Silver nanoparticles were prepared via metal vapor synthesis and introduced into the composite biopolymer matrix. An analysis of the small‐angle X‐ray scattering profiles revealed that silver nanoparticles are characterized by having a logarithmic normal size distribution with the maximum at 25 nm. The average size of particles determined from the broadening of diffraction peaks is in a good agreement with this result. The surface of the materials was characterized by X‐ray photoelectron spectroscopy. The in vitro release kinetics of ibuprofen in phosphate buffer solution with pH = 7.4 from prepared materials was studied. The drug release to solution is governed by Fickian diffusion and can be described within the Ritger–Peppas model. Introduction of silver nanoparticles has no effect on the diffusion mechanism. The as‐prepared materials are promising for the medical applications such as dressings for treatments of infected wounds and infection preventing. These materials can act as a matrix for transdermal drug administration. POLYM. ENG. SCI., 59:2479–2487, 2019. © 2019 Society of Plastics Engineers

The integration of copper nanoparticles as antifungal agents in polymeric matrices to produce copper polymer nanocomposites has shown excellent results in preventing the growth of a wide variety of toxigenic fungi. Copper-chitosan nanocomposite-based chitosan hydrogels (Cu-Chit/NCs hydrogel) were prepared using a metal vapor synthesis (MVS) and the resulting samples were described by transmission electron microscopy (TEM), X-ray fluorescence analysis (XRF), and small-angle X-ray scattering (SAXS). Aflatoxin-producing medium and VICAM aflatoxins tests were applied to evaluate their ability to produce aflatoxins through various strains of Aspergillus flavus associated with peanut meal and cotton seeds. Aflatoxin production capacity in four fungal media outlets revealed that 13 tested isolates were capable of producing both aflatoxin B1 and B2. Only 2 A. flavus isolates (Af11 and Af 20) fluoresced under UV light in the A. flavus and parasiticus Agar (AFPA) medium. PCR was completed using two specific primers targeting aflP and aflA genes involved in the synthetic track of aflatoxin. Nevertheless, the existence of aflP and aflA genes indicated some correlation with the development of aflatoxin. A unique DNA fragment of the expected 236 bp and 412 bp bands for aflP and aflA genes in A. flavus isolates, although non-PCR fragments have been observed in many other Aspergillus species. This study shows the antifungal activity of Cu-Chit/NCs hydrogels against aflatoxigenic strains of A. flavus. Our results reveal that the antifungal activity of nanocomposites in vitro can be effective depending on the type of fungal strain and nanocomposite concentration. SDS-PAGE and native proteins explain the apparent response of cellular proteins in the presence of Cu-Chit/NCs hydrogels. A. flavus treated with a high concentration of Cu-Chit/NCs hydrogels that can decrease or produce certain types of proteins. Cu-Chit/NCs hydrogel decreases the effect of G6DP isozyme while not affecting the activity of peroxidase isozymes in tested isolates. Additionally, microscopic measurements of scanning electron microscopy (SEM) showed damage to the fungal cell membranes. Cu-Chit/NCS hydrogel is an innovative nano-biopesticide produced by MVS is employed in food and feed to induce plant defense against toxigenic fungi.

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