Bactericidal and Fungistatic Properties of LDPE Modified with a Biocide Containing Metal Nanoparticles

Sputtering-Deposited Ultra-Thin Ag-Cu Films on Non-Woven Fabrics for Face Masks with Antimicrobial Function and Breath NOx Response

The multifunctional development in the field of face masks and the growing demand for scalable manufacturing have become increasingly prominent. In this study, we utilized high-vacuum magnetron sputtering technology to deposit a 5 nm ultra-thin Ag-Cu film on non-woven fabric and fabricated ultra-thin Ag-Cu film face masks. The antibacterial rates against Escherichia coli and Staphylococcus aureus were 99.996% and 99.978%, respectively, while the antiviral activity against influenza A virus H1N1 was 99.02%. Furthermore, the mask's ability to monitor respiratory system diseases was achieved through color change (from brownish-yellow to grey-white). The low cost and scalability potential of ultra-thin silver-copper film masks offer new possibilities for practical applications of multifunctional masks.

Enhanced antimicrobial efficacy of biogenic ZnO nanoparticles through UV-B activation: A novel approach for textile garment

Zinc oxide nanoparticles (ZnO NP) are characterized by novel properties which have been attracting the attention of different lines of research due to their wide applicability. Obtaining this nanomaterial is strongly linked to biogenic synthesis methods, which have also been developed in this research, using Coriandrum sativum extract as a reducing agent. ZnO NPs have been properly characterized by techniques to evaluate their morphology by transmission electron microscopy (TEM) and elemental analysis by EDX. The evaluation of the antimicrobial and antifungal effects is linked to the use of a system provided by "locker sanitizer" equipment, which has been designed and built as part of this research, and is intended to treat textile garments by nebulizing the ZnO NP colloid (99.08 μg/mL) + UV-B, water + UV-B, and UV-B only, and also to evaluate the influence of the treatment time for 1, 2 and 3 min. In this sense, it is known that the nanomaterial used shows a better response to UV light because more hydroxyl radicals are produced, leading to a higher reaction rate, which results in greater efficiency in inhibitory processes. The results show that the use of the locker sanitizer is more efficient when using ZnO NP + UV-B light since it achieved 100 % growth inhibition against E. coli, C. albicans, and A. brasiliensis, and >99 % against S. aureus, after 3 min of treatment.

The Promise of Metal-Doped Iron Oxide Nanoparticles as Antimicrobial Agent

Antibiotic resistance (AMR) is one of the pressing global public health concerns and projections indicate a potential 10 million fatalities by the year 2050. The decreasing effectiveness of commercially available antibiotics due to the drug resistance phenomenon has spurred research efforts to develop potent and safe antimicrobial agents. Iron oxide nanoparticles (IONPs), especially when doped with metals, have emerged as a promising avenue for combating microbial infections. Like IONPs, the antimicrobial activities of doped-IONPs are also linked to their surface charge, size, and shape. Doping metals on nanoparticles can alter the size and magnetic properties by reducing the energy band gap and combining electronic charges with spins. Furthermore, smaller metal-doped nanoparticles tend to exhibit enhanced antimicrobial activity due to their higher surface-to-volume ratio, facilitating greater interaction with bacterial cells. Moreover, metal doping can also lead to increased charge density in magnetic nanoparticles and thereby elevate reactive oxygen species (ROS) generation. These ROS play a vital role to disrupt bacterial cell membrane, proteins, or nucleic acids. In this review, we compared the antimicrobial activities of different doped-IONPs, elucidated their mechanism(s), and put forth opinions for improved biocompatibility.

Nanocomposites Based on Polyethylene and Nickel Ferrite: Preparation, Characterization, and Properties

Composite materials based on NiFe2O4 nanoparticles and polyethylene matrix have been synthesized by thermal decomposition to expand the application area of high-pressure polyethylene by filling it with nanoscale particles. The synthesized compositions were obtained in the form of a dark gray powder and compressed for further study According to TEM, the average particle size in composites was 2, 3, and 4 nm in samples with a filling of 10%, 20% and 30%. The concentration dependences of the specific electrical resistivity ρV, dielectric permittivity ε, saturation magnetization MS and the parameters of reflection and attenuation of microwave power of the obtained composites were investigated. The threshold for percolation in such materials is found to be within a concentration range of 20…30%. The electronic and atomic structure of composites was studied by methods of Mössbauer spectroscopy, X-ray diffraction and X-ray absorption spectroscopy. The closest atomic environment of nickel and iron in nanoparticles is close to that of crystalline NiFe2O4. The dependence of the nanoparticles size as well as the dependence of the number of tetrahedral or octahedral iron positions in nickel ferrite nanoparticles to their content in polyethylene matrix is established. It is shown that composite materials based on NiFe2O4 nanoparticles and polyethylene matrix can be used as components of electromagnetic compatibility systems.

A Bifunctional Spray Coating Reduces Contamination on Surfaces by Repelling and Killing Pathogens

Surface-mediated transmission of pathogens is a major concern with regard to the spread of infectious diseases. Current pathogen prevention methods on surfaces rely on the use of biocides, which aggravate the emergence of antimicrobial resistance and pose harmful health effects. In response, a bifunctional and substrate-independent spray coating is presented herein. The bifunctional coating relies on wrinkled polydimethylsiloxane microparticles, decorated with biocidal gold nanoparticles to induce a "repel and kill" effect against pathogens. Pathogen repellency is provided by the structural hierarchy of the microparticles and their surface chemistry, whereas the kill mechanism is achieved using functionalized gold nanoparticles embedded on the microparticles. Bacterial tests with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa reveal a 99.9% reduction in bacterial load on spray-coated surfaces, while antiviral tests with Phi6─a bacterial virus often used as a surrogate to SARS-CoV-2─demonstrate a 98% reduction in virus load on coated surfaces. The newly developed spray coating is versatile, easily applicable to various surfaces, and effective against various pathogens, making it suitable for reducing surface contamination in frequently touched, heavy traffic, and high-risk surfaces.

Bactericidal Properties of Low-Density Polyethylene (LDPE) Modified with Commercial Additives Used for Food Protection in the Food Industry

This study investigated the influence of commercially available food preservatives: Natamax® (containing natamycin) and Nisaplin® (containing nisin) on the antimicrobial properties of LDPE film, commonly used for food packaging. Studies have shown that the addition of 3% Natamax® or, alternatively, the addition of 5% Nisaplin® provides an LDPE film with effective antimicrobial protection. The applied biocides did not significantly affect the strength and rheological properties of LDPE. However, differences in optical properties were observed. The transparency of the samples decreased slightly with the addition of 3% or 5% Natamax® (by approx. 1% and 3%, respectively). A significant change was observed in the film haze, the addition of 5% Natamax® increased this parameter by approx. 80%, while 5% Nisaplin® increased it by approx. 19%. Both Natamax® and Nisaplin® agents can be successfully used to manufacture food packaging materials with antimicrobial protection. Natamax® showed a stronger bactericidal effect, while Nisaplin® changed other properties less significantly.

Application of innovative packaging technologies to manage fungi and mycotoxin contamination in agricultural products: Current status, challenges, and perspectives

The consumer demand for safe, "healthy," and premium foods, preferably with an extended shelf-life; demand for easy packaging; and choice for more sustainable food packaging have contributed to the development of novel packaging technologies. The application of adequate packaging materials has recently become a major post-harvest challenge concerning the control of fungi and mycotoxin. This review will describe the current antifungal packaging technology involved to prevent the contamination of fungi and mycotoxin, along with the characteristics and mechanism of action in food products. Antifungal packaging has incredible potential in the food packaging sector. The most suitable approach for the safe storage of agricultural produce for farmers is the hermetic packaging technology, which maintains quality while providing a good barrier against fungi and mycotoxin. Furthermore, active antifungal packaging is a viable method for incorporating antifungal agents against pathogenic fungi. Essential oils and organic acid have received more scientific attention due to their increased efficacy against mold growth. Polypeptides, chitosan, and natamycin incorporated in active packaging significantly reduced fungi. Even though nanotechnological advancements in antifungal packaging are promising, safety and regulation issues remain significant concerns.

Legionella pneumophila-Virulence Factors and the Possibility of Infection in Dental Practice

Legionella pneumophila is defined as a bacterium that can cause severe pneumonia. It is found in the natural environment and in water, and is often found in water tanks. It can be an integral part of biofilms in nature, and the protozoa in which it can live provide it with food and protect it from harmful influences; therefore, it has the ability to move into a sustainable but uncultured state (VBNC). L. pneumophila has been shown to cause infections in dental practices. The most common transmission route is aerosol generated in dental office water systems, which can negatively affect patients and healthcare professionals. The most common way of becoming infected with L. pneumophila in a dental office is through water from dental instruments, and the dental unit. In addition to these bacteria, patients and the dental team may be exposed to other harmful bacteria and viruses. Therefore, it is vital that the dental team regularly maintains and decontaminates the dental unit, and sterilizes all accessories that come with it. In addition, regular water control in dental offices is necessary.

Hydration of Cement in the Presence of Biocidal Modifiers Based on Metal Hydrosilicates

This article presents the results of a study of the characteristics of hydration and properties of a composite biocidal cement binder containing hydrosilicates of barium, copper or zinc. It was found that copper hydrosilicates block hydration processes, and when zinc hydrosilicates are used, the rate of hydration is determined by the content of silicic acid. The limiting concentrations of biocidal modifiers have been established: zinc hydrosilicates—no more than 4% and copper hydrosilicates—no more than 0.5%, which are advisable to use for the manufacture of a biocidal composite binder. It is shown that modifying additives slow down the setting time, the amount of tricalcium silicate in cement stones increases, and their strength for some compositions decreases. Active binding of portlandite with the formation of calcium hydrosilicates occurs when the content of zinc hydrosilicates is 2%, which leads to an increase in the strength of the materials.