Frederico Nogueira

Chronic wounds, pressure sores, lesions, and infections of microbial origin in bedridden, paralyzed, or malnutrition patients remain the object of study of many researchers. A variety of factors behind the development of these disorders are related to the patient's immune system, making it unable to respond effectively to the treatment of the wound. These factors can be properly controlled, giving particular importance to the ethiology and stage of the wound, as well as the time periods corresponding to the replacement of the dressings. The present research reports a novel foam/soft material, L-Cys-g-PCL, with an application for decubitus/pressure ulcers, especially for wounds with a difficult healing process due to infections and constant oxidation of the soft tissues. During this work, the interactions between S. aureus and L-Cys-g-PCL foam were studied under conditions that simulate decubitus ulcers; namely, pH and exudate. The effects of duration of grafting (1 or 8 h) and pH (7.0 and 8.9) on wettability, surface energy, swelling, and porosity were also evaluated. Results showed an effective microbicidal activity exhibiting an inhibition ratio of 99.73% against S. aureus. This new L-Cys-g-PCL soft material showed saftey to contact skin, ability to be shaped to fill in sunken holes (craters) - pressure ulcers stage III - and to act as a smart material responsive to pH, which can be tailored to develop better swelling properties at alkaline pH where exudates are normally higher, so as to address exudate self-cleaning and prevention of desiccation..

Sensitive skin diseases, including atopic dermatitis, skin inflammation and bedsores, leave patients vulnerable under hospital setting. It is important for the development of a hospital gown with “soft hand” properties and at the same time as a protector against nosocomial infections. Klebsiella pneumoniae has developed resistance to antibiotics in the carbapenem antibiotic class, known as carbapenem-resistant K. pneumoniae (CRKP). CRKP is resistant to nearly all antibiotics and can kill up to 50% of infected patients. This work consisted in the development of a washable recycled silk fibroin-based gown covalently linked with an amino acid l-Cysteine(l-Cys), focused on prevention of K. pneumoniae establishment, proliferation and spreading to community, for use under hospital settings. With the growing problem of resistance to antibiotics and few new therapies on the horizon, gowns adsorbed with L-Cys show to function as a barrier to the establishment and proliferation of microorganisms, providing user protection from infectious disease. This gown was knitted at a rectilinear needle loom with a Jersey knit structure. Then it was cross-linked with l-Cys, subjected to laundry, and subsequently characterized by energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, contact angle, free energy of adhesion, scanning electron microscopy and transmission electron microscopy. Results presented a bactericidal effect against K. pneumoniae of 94.92% after three rinses and 88.88% after five washing cycles, with the few adhered bacteria with an altered and compromised morphology.

Wounds are the ideal setting for the development of micro‐organisms, so it is often necessary to apply a dressing to control bacterial colonization. Cotton is commonly used in dressings, as it exhibits important hydrophilic characteristics such as high moisture and fluid retention properties, but it may provide a sustainable media for the development of micro‐organisms. In this way, the development of new strategies to provide cotton materials with lasting and effective antimicrobial properties is of the utmost importance. Consequently, here we described two processes to develop cotton‐dressings functionalized with antimicrobial peptides (AMPs) magainin I (MagI) and LL‐37, in order to give cotton‐dressings an antibacterial effect. The AMPs showed no cytotoxic effect against human fibroblasts so they are safe to contact with skin. In addition, the functionalized materials with either LL‐37 or MagI present an antimicrobial effect exhibiting inhibition ratios of 89% against Klebsiella pneumoniae and 58% against Staphylococcus aureus, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40997.