SANDRA KISELIOVIENĖ
KAUNAS UNIVERSITY OF TECHNOLOGY
Doctoral dissertation
Physical sciences, chemistry (03P)
2016, Kaunas
INTRODUCTION
Skin lesions are inevitable processes, and many have used bandages or patches. Historically, the dressing of wounds was carried out through the use of cloth. Recently, in chemistry and material sciences, a new generation of wound dressings has been extensively developed. Dressings made of new forms such as sponges, films and hydrocolloids have been developed together with new functions. Modern bandages not only protect the wound from infection, but as well promote the healing process, irrigate the wound, absorb the wound secretions, achieve the desired pH of the wound medium, stimulate the necessary growth factors and carry active compounds into the wound. Therefore, it is very important to perform a variety of chemical investigations. In recent years, a number of new products adapted for different types of wound healing and the wound healing stages have been discovered. The new generation of bandages has developed taking into account the different biological mechanisms that promote the healing of the wound, as well as comfortable feeling for patient, good mechanical, fluid absorption and antimicrobial properties are being developed.
In the past, the bandages were made of the cotton fabric (cellulose) with a different degree of wound exudate absorbency. The primary function of these bandages was to keep the wound dry, let the exudate evaporate and protect the wound against the harmful bacteria. However, only several decades ago, it has been observed that faster and more successful wound healing is achieved in the wet environment. Wound dressing should create an optimal environment that allows unrestricted movement of epithelial cells in order to achieve a faster wound healing process. The optimal conditions for wound healing are a moist environment around the wound and an effective oxygen circulation, which promotes cell and tissue regeneration. The type of wound has a significant influence on the wound development process, as the variety of wounds is distinguished, for example, chronic, necrotic, sloughy and epithelializing.
Modern materials that are used to cover the wound can be divided into inert, interacting with skin and biologically active substances. Natural polymers (collagen, alginates, chitosan, cellulose derivatives, etc.) are widely used for the non-healing wounds. Moreover, the synthetic polymers due to their air, water vapour permeability, prevention of bacteria entry into wounds are used. Efficient wound healing depends on many factors, including the type of wound, the treatment process, the patient health status (e.g. diabetes), environmental and social conditions, physico-chemical properties of the bandages.
Cellulose as a natural, non-irritant, nontoxic, biocompatible, environmentally friendly material is widely used as a wound healing material. As a wound dressing, cellulose is used in various forms. In the early years, firstly, cellulose was used as gauzes. Nowadays, more improved cellulose forms for wound healing are investigated, for example, cellulose fibers, cellulose films, sponges. As a hydrogel form is becoming more and more popular, cellulose hydrogels are becoming a field of interest as well.