In situ synthesis of silver or selenium nanoparticles on cationized cellulose fabrics for antimicrobial application.

In this study, we developed a method to prepare inorganic nanoparticles in situ on the surface of cationized cellulose using a rapid microwave-assisted synthesis. Selenium nanoparticles (SeNPs) were employed as a novel type of antimicrobial agent and, using the same method, silver nanoparticles (AgNPs) were also prepared. The results demonstrated that both SeNPs and AgNPs of about 100 nm in size were generated on the cationized cellulose fabrics. The antibacterial tests revealed that the presence of SeNPs clearly improved the antibacterial performance of cationized cellulose in a similar way as AgNPs. The functionalised fabrics demonstrated strong antibacterial activity when assessed using the challenge test method, even after repeated washing. Microscopic investigations revealed that the bacterial cells were visually damaged through contact with the functionalised fabrics. Furthermore, the functionalised fabrics showed low cytotoxicity towards human cells when tested in vitro using an indirect contact method. In conclusion, this study provides a new approach to prepare cationic cellulose fabrics functionalised with Se or Ag nanoparticles, which exhibit excellent antimicrobial performance, low cytotoxicity and good laundry durability. We have demonstrated that SeNPs can be a good alternative to AgNPs and the functionalised fabrics have great potential to serve as an anti-infective material.

A Comprehensive Review of Topical Odor-Controlling Treatment Options for Chronic Wounds.

The process of wound healing is often accompanied by bacterial infection or critical colonization, resulting in protracted inflammation, delayed reepithelization, and production of pungent odors. The malodor produced by these wounds may lower health-related quality of life and produce psychological discomfort and social isolation. Current management focuses on reducing bacterial activity within the wound site and absorbing malodorous gases. For example, charcoal-based materials have been incorporated into dressing for direct adsorption of the responsible gases. In addition, multiple topical agents, including silver, iodine, honey, sugar, and essential oils, have been suggested for incorporation into dressings in an attempt to control the underlying bacterial infection. This review describes options for controlling malodor in chronic wounds, the benefits and drawbacks of each topical agent, and their mode of action. We also discuss the use of subjective odor evaluation techniques to assess the efficacy of odor-controlling therapies. The perspectives of employing novel biomaterials and technologies for wound odor management are also presented.

Absence of premature senescence in Werner's syndrome keratinocytes.

Werner's syndrome (WS) is an autosomal recessive genetic disorder caused by loss of function mutation in wrn and is a useful model of premature in vivo ageing. Cellular senescence is a plausible causal mechanism of mammalian ageing and, at the cellular level, WS fibroblasts show premature senescence resulting from a combination of telomeric attrition and replication fork stalling. Over 90% of WS fibroblast cultures achieve <20 population doublings (PD) in vitro compared to wild type human fibroblast cultures. It has been proposed that some cell types, capable of proliferation, will fail to show a premature senescence phenotype in response to wrn mutations. To test this hypothesis, human dermal keratinocytes (derived from both WS and wild type patients) were cultured long term. WS Keratinocytes showed a replicative lifespan in excess of 100 population doublings but maintained functional growth arrest mechanisms based on p16 and p53. The karyotype of the cells was superficially normal and the cultures retained markers characteristic of keratinocyte holoclones (stem cells) including p63 expression and telomerase activity. Accordingly we conclude that, in contrast to WS fibroblasts, WS keratinocytes do not demonstrate slow growth rates or features of premature senescence. These findings suggest that the epidermis is among the tissue types that do not display symptoms of premature ageing caused by loss of function of wrn. This is in support that Werner's syndrome is a segmental progeroid syndrome.

Bacteriophage-nanocomposites: an easy and reproducible method for the construction, handling, storage and transport of conjugates for deployment of bacteriophages active against Pseudomonas aeruginosa.

The purpose of this work was proof of concept to develop a novel, cost effective protocol for the binding of bacteriophages to a surface without loss of function, after storage in various media. The technology platform involved covalently bonding bacteriophage 13 (a Pseudomonas aeruginosa bacteriophage) to two magnetised multiwalled carbon nanotube scaffolds using a series of buffers; bacteriophage-nanotube (B-N) conjugates were efficacious after storage at 20 °C for six weeks. B-N conjugates were added to human cell culture in vitro for 9 days without causing necrosis and apoptosis. B-N conjugates were frozen (-20 °C) in cell culture media for several weeks, after which recovery from the human cell culture medium was possible using a simple magnetic separation technique. The retention of viral infective potential was demonstrated by subsequent spread plating onto lawns of susceptible P. aeruginosa. Analysis of the human cell culture medium revealed the production of interleukins by the human fibroblasts upon exposure to the bacteriophage. One day after exposure, IL-8 levels transitorily increased between 60 and 100 pg/mL, but this level was not found on any subsequent days, suggesting an initial but not long lasting response. This paper outlines the development of a method to deliver antimicrobial activity to a surface that is small enough to be combined with other materials. To our knowledge at time of publication, this is the first report of magnetically coupled bacteriophages specific to human pathogens which can be recovered from test systems, and could represent a novel means to conditionally deploy antibacterial agents into living eukaryotic systems without the risks of some antibiotic therapies.