In the current work, a new antibacterial bandage was proposed where diamond-like carbon with silver nanoparticle (DLC:Ag)-coated synthetic silk tissue was used as a building block. The DLC:Ag structure, the dimensions of nanoparticles, the silver concentration and the silver ion release were studied systematically employing scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic absorption spectroscopy, respectively. Antimicrobial properties were investigated using microbiological tests (disk diffusion method and spread-plate technique). The DLC:Ag layer was stabilized on the surface of the bandage using a thin layer of medical grade gelatin and cellulose. Four different strains of Staphylococcus aureus extracted from humans’ and animals’ infected wounds were used. It is demonstrated that the efficiency of the Ag+ ion release to the aqueous media can be increased by further RF oxygen plasma etching of the nanocomposite. It was obtained that the best antibacterial properties were demonstrated by the plasma-processed DLC:Ag layer having a 3.12 at % Ag surface concentration with the dominating linear dimensions of nanoparticles being 23.7 nm. An extra protective layer made from cellulose and gelatin with agar contributed to the accumulation and efficient release of silver ions to the aqueous media, increasing bandage antimicrobial efficiency up to 50% as compared to the single DLC:Ag layer on textile.

Superhydrophobic surfaces are important parts of many applications in cleaning and protective coatings. Such surfaces can be realized by controlling the surface chemistry and nanoscale structure. Elongated ZnO nanostructures, called nanowires, are often used in superhydrophobic applications due to their intrinsic characteristic advantages and simple synthesis control. This review presents a critical overview of the latest research activities focused on the ZnO nanowire superhydrophobic surfaces. A wettability mechanism background is introduced with the overlay of the crystal structure fundamentals adapted for ZnO nanowires to gain insights into the multifunction application of superhydrophobic ZnO nanowires. Moreover, the latest achievements in application of ZnO superhydrophobic nanowires or reversible wettability for self-cleaning, separation, antifogging, antibacterial, and other applications are outlined. Finally, a brief outlook on the issues and emerging perspectives of ZnO nanowire wettability research is summarized.

A growing number of severe infections are related to antibiotic-resistant bacteria, therefore, in recent years, alternative antimicrobial materials based on silver nanoparticles (NPs) attracted a lot of attention. In the current research, we present a medical patch prototype containing diamond-like carbon nanocomposite thin films doped with silver nanoparticles (DLC:Ag), as a source of silver ions, and an aqueous mass of the gelatin/agar mixture as a silver ion accumulation layer. The DLC:Ag thin films with 3.4 at.% of silver were deposited on synthetic silk employing reactive unbalanced DC magnetron sputtering of the silver target with argon ions performed in the acetylene gas atmosphere. The average size of the silver nanoparticles as defined by scanning electron microscope was 24 nm. After the film deposition, the samples were etched with RF oxygen plasma, aiming at efficient silver ion release in aqueous media from the nanocomposite film. In the patch prototype, a mixture of agar and gelatin was applied in silicone carrier with cavities, acting as a silver ion accumulation layer that further enhanced the antimicrobial efficiency. It was found that the DLC:Ag thin film on the silk after soaking in water for 24 h was able to release up to 4 ppm of Ag. The microbiological experiments using S. aureus bacteria were performed with the patch prototype and the silver ion saturated water, demonstrated the inactivation of 99% and 79% of bacteria, respectively. Scanning electron microscopy analysis showed that silver NPs destroyed the bacteria cell and the bacteria affected by Ag ions had spots and perforated cell wall areas with cytoplasm leakage out was obtained. A preliminary preclinical study using the laboratory animals demonstrated that using the patch prototype, the methicillin-resistant S. aureus (MRSA)-infected wound on skin surface healed faster compared with control and was able to kill all MRSA bacteria strains in the wound’s bed after 72 h of treatment.

Nonlinear optical properties (self-saturable absorption and reverse-saturable absorption) of diamond-like carbon films with variable amounts of embedded copper nanoparticle (DLC:Cu) films deposited by high power pulse magnetron sputtering were studied in dependence on deposition conditions. X-ray photoelectron spectroscopy was used to study elemental composition and He ion microscopy to study changes of the size, shape, and concentration of the Cu nanoparticles deposited using different pulse currents as well as argon and acetylene gas ratios. Raman scattering spectra of DLC:Cu films studied were typical of diamond-like carbon (including the films with a high Cu atomic concentration where it was up to 60 atom % and carbon atomic concentration was less than 20 atom %). In all cases, in the absorption spectra of DLC:Cu films, the surface plasmon resonance-related peak was recorded. The position of the plasmonic peak for all the deposited nanocomposite films was in a 590–620 nm range. For the samples containing lower amounts of copper, reverse-saturable absorption was found. Transient optical absorption measurements have shown that the reverse-saturable absorption is typical for the samples with a lower relaxation time. The longer relaxation times recorded during transient optical absorption measurements correlated with the presence of the saturable absorption effect. For DLC:Cu samples containing 58–62 atom % Cu, some optical inhomogeneities were observed. The samples in different places demonstrated either saturable absorption or reverse-saturable absorption. The presence of both saturable and reverse-saturable absorption effects in the same sample is explained by the lateral inhomogeneities of the DLC:Cu films.

No abstract