Antimicrobial Double-Layer Coating Prepared from Pure or Doped-Titanium Dioxide and Binders

Paper-based material with hydrophobic and antimicrobial properties: Advanced packaging materials for food applications

The environmental challenges posed by plastic pollution have prompted the exploration of eco-friendly alternatives to disposable plastic packaging and utensils. Paper-based materials, derived from renewable resources such as wood pulp, non-wood pulp (bamboo pulp, straw pulp, reed pulp, etc.), and recycled paper fibers, are distinguished by their recyclability and biodegradability, making them promising substitutes in the field of plastic food packaging. Despite their merits, challenges like porosity, hydrophilicity, limited barrier properties, and a lack of functionality have restricted their packaging potential. To address these constraints, researchers have introduced antimicrobial agents, hydrophobic substances, and other functional components to improve both physical and functional properties. This enhancement has resulted in notable improvements in food preservation outcomes in real-world scenarios. This paper offers a comprehensive review of recent progress in hydrophobic antimicrobial paper-based materials. In addition to outlining the characteristics and functions of commonly used antimicrobial substances in food packaging, it consolidates the current research landscape and preparation techniques for hydrophobic paper. Furthermore, the paper explores the practical applications of hydrophobic antimicrobial paper-based materials in agricultural produce, meat, and seafood, as well as ready-to-eat food packaging. Finally, challenges in production, application, and recycling processes are outlined to ensure safety and efficacy, and prospects for the future development of antimicrobial hydrophobic paper-based materials are discussed. Overall, the emergence of hydrophobic antimicrobial paper-based materials stands out as a robust alternative to plastic food packaging, offering a compelling solution with superior food preservation capabilities. In the future, paper-based materials with antimicrobial and hydrophobic functionalities are expected to further enhance food safety as promising packaging materials.

Antimicrobial Photodynamic Coatings Reduce the Microbial Burden on Environmental Surfaces in Public Transportation—A Field Study in Buses

Millions of people use public transportation daily worldwide and frequently touch surfaces, thereby producing a reservoir of microorganisms on surfaces increasing the risk of transmission. Constant occupation makes sufficient cleaning difficult to achieve. Thus, an autonomous, permanent, antimicrobial coating (AMC) could keep down the microbial burden on such surfaces. A photodynamic AMC was applied to frequently touched surfaces in buses. The microbial burden (colony forming units, cfu) was determined weekly and compared to equivalent surfaces in buses without AMC (references). The microbial burden ranged from 0–209 cfu/cm² on references and from 0–54 cfu/cm² on AMC. The means were 13.4 ± 29.6 cfu/cm² on references and 4.5 ± 8.4 cfu/cm² on AMC (p < 0.001). The difference in microbial burden on AMC and references was almost constant throughout the study. Considering a hygiene benchmark of 5 cfu/cm², the data yield an absolute risk reduction of 22.6% and a relative risk reduction of 50.7%. In conclusion, photodynamic AMC kept down the microbial burden, reducing the risk of transmission of microorganisms. AMC permanently and autonomously contributes to hygienic conditions on surfaces in public transportation. Photodynamic AMC therefore are suitable for reducing the microbial load and closing hygiene gaps in public transportation.

Antimicrobial coatings for environmental surfaces in hospitals: a potential new pillar for prevention strategies in hygiene

Recent reports provide evidence that contaminated healthcare environments represent major sources for the acquisition and transmission of pathogens. Antimicrobial coatings (AMC) may permanently and autonomously reduce the contamination of such environmental surfaces complementing standard hygiene procedures. This review provides an overview of the current status of AMC and the demands to enable a rational application of AMC in health care settings. Firstly, a suitable laboratory test norm is required that adequately quantifies the efficacy of AMC. In particular, the frequently used wet testing (e.g. ISO 22196) must be replaced by testing under realistic, dry surface conditions. Secondly, field studies should be mandatory to provide evidence for antimicrobial efficacy under real-life conditions. The antimicrobial efficacy should be correlated to the rate of nosocomial transmission at least. Thirdly, the respective AMC technology should not add additional bacterial resistance development induced by the biocidal agents and co- or cross-resistance with antibiotic substances. Lastly, the biocidal substances used in AMC should be safe for humans and the environment. These measures should help to achieve a broader acceptance for AMC in healthcare settings and beyond. Technologies like the photodynamic approach already fulfil most of these AMC requirements.

Antibacterial Properties of Zn Doped Hydrophobic SiO2 Coatings Produced by Sol-Gel Method

Bacteria existing on the surfaces of various materials can be both a source of infection and an obstacle to the proper functioning of structures. Increased resistance to colonization by microorganisms can be obtained by applying antibacterial coatings. This paper describes the influence of surface wettability and amount of antibacterial additive (Zn) on bacteria settlement on modified SiO2-based coatings. The coatings were made by sol-gel method. The sols were prepared on the basis of tetraethoxysilane (TEOS), modified with methyltrimethoxysilane (MTMS), hexamethyldisilazane (HMDS) and the addition of zinc nitrate or zinc acetate. Roughness and surface wettability tests, as well as study of the chemical structure of the coatings were carried out. The antibacterial properties of the coatings were checked by examining their susceptibility to colonization by Escherichia coli. It was found that the addition of zinc compound reduced the susceptibility to colonization by E. coli, while in the studied range, roughness and hydrophobicity did not affect the level of bacteria adhesion to the coatings.