Functionalization of textile structures with natural additives for high absorption dressing materials

Abstract

Considering the technological evolution and the limitations related to the existing dressing materials, the development of new and advanced devices that offer a successful and cost-effective response in wound care is essential. Characteristics such as moisture control, exudate extraction, long-lasting application and antibacterial activity are very desired in a dressing. With this, the aim of this project was to incorporate additives in a textile structure that would enhance its properties, so that it could be posteriorly included in a multi-layered high-absorption bandage for wound treatment. Aloe vera and sunflower oil are natural additives with moisturizing, anti-inflammatory and antimicrobial activities. They were selected for this work and, in order to achieve a controlled release of the active agents, were encapsulated through external ionic gelation. Regarding the wall of the capsules, different materials were tested: shellac, eudragit, alginate and chitosan. For a controlled and specific release, pH-dependent release studies were then performed on the capsules to evaluate which capsules were more suitable for the wound microenvironment. Additional characterization methods were used, and the capsules were incorporated in the textile, using different impregnation solutions. With this work, several interesting developments were made. As results, homogeneous and spherical capsules, with diameters bellow 1000 μm, were successfully produced after the incorporation of compressed air in their formation procedure. The alginate-chitosan capsules formed through the layer-by-layer method have proven to provide a suitable pH-dependent release suitable for wound healing. A greater and faster release was achieved at pH 7.5, followed by pH 9 and lastly pH 6, which is appropriate since the pH of a wound is around 6-7.5, increasing to a pH range between 7 and 9 when infected. Additionally, a higher number of layers was able to deliver a slower release in general, offering a more long-lasting effect. In these aspects, these capsules were proven to be superior to other capsules: shellac-alginate, Eudragit-coated alginate and alginate only capsules. Regarding impregnation, through the pouring of the dispersions in the textile, all the capsules made with compressed air were fixated to the textile structure. With this, glutaraldehyde and citric acid appeared to be the most fitting crosslinkers, compared to glyoxal, which might destroy slightly the capsules. In the future, further characterization methods would have to be used for the detection of sunflower oil and Aloe vera in the capsules, such as gas and liquid chromatography. Improvements in the impregnation dispersion consistency is also necessary for a more homogenized distribution of the capsules.

Date of Award	4 Nov 2022
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Maria Helena Pereira Vilaça (Supervisor)