Introduction: Bacterial infections caused by different strains of bacteria still one of the most important disorders affecting humans worldwide. Polymers nanocomposite systems could be considered as an alternative to conventional antibiotics to eradicate bacterial infections. Significance: In an attempt to enhance the antibacterial performance of silver and iron oxide nanoparticles, decrease their aggregation and toxicity, a polymeric hybrid nanocomposite system combining both nanoparticles is produced. Methods: Magnetic Ag–Fe3O4@polymer hybrid nanocomposites prepared using different polymers, namely polyethylene glycol 4000, ethyl cellulose, and chitosan were synthesized via wet impregnation and ball-milling techniques. The produced nanocomposites were tested for their physical properties and antibacterial activities. Results: XRD, FT-IR, VSM, and TEM results confirmed the successful preparation of hybrid nanocomposites. Hybrid nanocomposites have average crystallite sizes in the following order Ag–Fe3O4@CS (8.9 nm) < Ag– Fe3O4@EC (9.0 nm) < Ag–Fe3O4@PEG4000 (9.4 nm) and active surface area of this trend Ag–Fe3O4@CS (130.4 m2 g−1 ) > Ag–Fe3O4@EC (128.9 m2 g−1 ) > Ag–Fe3O4@PEG4000 (123.4 m2 g−1 ). In addition, they have a saturation magnetization in this order: Ag–Fe3O4@PEG4000 (44.82 emu/g) > Ag–Fe3O4@EC (40.14 emu/ g) > Ag–Fe3O4@CS (22.90 emu/g). Hybrid nanocomposites have a pronounced antibacterial action against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus intermedius compared to iron oxide nanoparticles and positive antibacterial drug. In addition, both Ag–Fe3O4@EC and Ag–Fe3O4@CS have a lower MIC values compared to Ag–Fe3O4@PEG and positive control. Conclusion: Magnetic Ag–Fe3O4 hybrid nanocomposites could be promising antibacterial nanomaterials and could pave the way for the development of new materials with even more unique properties and applications.

In this work, pure Co3O4, Ni-, CuNi-, and CdNi-doped Co3O4 nanoparticles (NPs) were prepared via chemical coprecipitation method. The obtained Co3O4 exhibits a cubic crystalline structure with an average crystallite size of ~19.9 nm, according to the XRD profiles. Moreover, the effects of Ni-, CuNi- and CdNi-doped Co3O4 on the crystallite size, band gap, and magnetic properties of the cubic Co3O4 were considered. It was observed that the crystallite sizes and the magnetic properties of Ni(0.1)Co3O4(0.9) and Cu(0.05)Ni(0.05)Co3O4(0.9) samples are smaller, while the optical band gaps are wider than that of pure Co3O4. The Cd(0.05)Ni(0.05)Co3O4(0.9) sample has a higher magnetic properties in comparison to the other samples. The elemental composition of the produced Co3O4, Ni-, CuNi- and CdNi-doped Co3O4 NPs is determined using the EDX technique. A morphological study by TEM showed that the CdNi-doped Co3O4 sample has semi-spherical particles with an average particle diameter of ~70.4 nm. The photodegradation of methyl orange (MO) dye in aqueous solution under visible light irradiation was used to examine the catalytic activity of pure and doped Co3O4 NPs. The results showed that the degradation of MO dye was improved in the doped samples and takes the following order: Cd(0.05)Ni(0.05)Co3O4(0.9) (~93%) > Cu(0.05)Ni(0.05)Co3O4(0.9) (~85%) > Ni(0.1)Co3O4(0.9) (~79.7%) > pure Co3O4 (~64.4%) in 120 min of irradiation time. The pseudo-first-order reaction rate constant for Cd(0.05)Ni(0.05)Co3O4(0.9) is equal to 0.021 min− 1 , which is about 1.6-times increased in compared to pure Co3O4. The improved photocatalytic efficiency of this sample was attributed to an extrinsic defect generated by CdNi doping, small particle sized and high surface area, which delayed the electron/hole recombination and caused appropriate band gap configuration

Metallic nanoparticles embedded in the polymer matrix are considered a significant category of heterogeneous catalysts with strong catalytic performance. Functionalized polymers are inexpensive building blocks that make good catalytic platforms for stabilizing metallic nanoparticles. In this study, Fe3O4@CMC-Cu magnetic nanocomposites were successfully synthesized and characterized by XRD, FTIR, BET, XPS, VSM, HR-TEM, and EDX mapping. Morphology observation shows that spherical Fe3O4 magnetic nanoparticles and Cu NPs are distributed uniformly and encapsulated inside the polymer structure with an average diameter of ~ 11 nm without substantial agglomeration. Additionally, the inclusion of CMC polymer and Cu NPs gradually reduces the magnetic saturation of Fe3O4. The reduction of 4-nitrophenol (4-NP) and the organic dyes Congo red (CR) and acriflavine (ACF) in aqueous medium at room temperature was used to test the nanocomposites’ catalytic activity. The effects of reaction parameters, catalyst amount and Cu NPs percentages on the catalytic effectiveness were determined. The induction time of the reaction decreases with increasing the nanocomposite amount and the Cu NPs loading percentages. Excellent catalytic activity was demonstrated by the Fe3O4@CMC-Cu (10 %) nanocomposite for the elimination of all three intended organic contaminants (4-NP, CR and ACF). For the reduction of 4-NP, CR, and ACF, the calculated Kapp values were 1.55 min− 1 , 0.3 min− 1 , and 2.3 min− 1 , respectively. The magnetic nanocomposite was easily separated from the reaction solution and recycled for up to five successive cycles without suffering a substantial decrease in the catalytic activity. Such magnetic nanocomposites provide light on highly effective catalysts for applications in environmental protection

Lead sulfide nanoparticles were hydrothermally synthesized
and their size was diminished via exposure to ultrasound
waves. Both h-PbS and h,us-PbS nanoparticles of
different sizes were characterized using powder X-ray
diffraction, TEM microscopy and surface area measurements.
The nanoparticles limited the growth of Aspergillus
pathogens and light microscopy proved severe morphological
abnormalities in the fungal vesicles, conidiophores and
mycelia in response to the nanoparticles.

The introduction of fish skin as a biological dressing for treating burns and wounds holds great
promise, offering an alternative to existing management strategies. However, the risk of disease
transmission is a significant concern. Therefore, this study aimed to examine how established
sterilization and preservation procedures affected fish skin grafts’ microbiological and histological
properties for long‑term usage. Lyophilization of the fish skin graft followed by rehydration in
normal saline for 15 min did not change the collagen content. Furthermore, gamma irradiation of
the lyophilized fish skin graft at different lengths 5, 10, and 25 KGy showed a significant reduction in
microbial growth (aerobic bacteria, aerobic yeasts, and fungi) at 15‑ and 30 days after the irradiation.
However, exposure to 10 KGy was found to be the most effective intensity among the different
gamma irradiation lengths since it preserved the collagen fiber content and intensity in the lyophilized
fish skin grafts at 15‑ and 30 days after the irradiation. These findings provide efficient preservation
and sterilization methods for long‑term usage of the fresh Tilapia skin grafts used for biological
dressings.