Active wound dressings providing photodynamic treatment

Active hydrogel dressing containing photosensitizing agent (PS) was obtained with this thesis study. Light-activated photodynamic therapy (PDT) has long been used in dermatology, carcinology, otolaryngology, gynecology, gastroenterology, urology, etc. and it's a type of treatment that approved for various diseases. PS used in PDT is a substance that can absorb light with the suitable wavelength and form reactive oxygen species (ROS). ROS shows antimicrobial activity by producing cytotoxic effects in target cells without mutagenic or genotoxic effects. In addition, microorganisms cannot develop resistance in this process. The light-induced formation of the harmful radicals such as reactive oxygen (ROS) and reactive nitrogen (RNS) species that are capable of killing cells depends on the intensity and the wavelength of the light and the type and amount of the PS used. It is envisaged that the concentration of these reactive species studied in the thesis study will be adjusted by various factors so as to eliminate the internal and external microorganisms that can cause infection in the damaged tissue without causing harm to healthy tissues. Furthermore, the hydrogel dressings containing a fixed photosensitizer dye in the matrix are synthesized so as to protect the moisture balance on the wound area, to promote tissue formation, to reduce pain by cooling the wound area, to prevent the contamination of the wound while being permeable to gases and to contribute to the healing of the wound by absorbing excess liquid formed by the damaged tissue. In the thesis study, many parameters such as tensile-rupture, gelling, dissolution percentage and swelling behavior at different pH and temperature were examined for all systems obtained from natural, hybrid and synthetic polymers. Antibacterial analysis of the systems loaded with different PS agents was conducted against E. coli (ATCC 11775) and S. aureus (ATCC 25923) by using a modified version of JIS Z 2801 standard. Cell migration and MTT tests were performed using L929 fibroblast cells. As a result of the studies, it was determined that the hydrogel dressing that consists of synthetic polymers shows an antibacterial effect between the values of log2 - log3 and the photosensitizer substance used supports cell migration without toxic effects.