Author: Nikolay Estiven Gomez Mesa
Gomez Mesa, Nikolay Estiven, 2025 Integration of Aggregation-Induced Emission Photosensitizers into Casein Nanofibers for Antibacterial Applications in Epidermolysis Bullosa, Flinders University, College of Medicine and Public Health
Terms of Use: This electronic version is (or will be) made publicly available by Flinders University in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. You may use this material for uses permitted under the Copyright Act 1968. If you are the owner of any included third party copyright material and/or you believe that any material has been made available without permission of the copyright owner please contact copyright@flinders.edu.au with the details.
The fragile skin disorders continue to present a major challenge globally both in clinical care and biomedical research. Among them, Epidermolysis Bullosa (EB) is a debilitating hereditary disorder of the skin that has no known cure. In the absence of a curative treatment, current research is focused on efficient wound management with the aim of decreasing complications and improving quality of life. These wounds are often complicated by bacterial infections, thus significantly increasing patient morbidity. Commercial dressings available, such as silver-loaded or synthetic polymer membranes, can provide only limited protection and in cases may adhere to skin, cause delayed healing, or cytotoxicity upon frequent replacement, especially for these individuals with delicate skin. In light of these challenges, this project explored the potential of nature-derived polymers for wound care due to their biocompatibility, cost-effectiveness, and the potential of support the healing process. Casein, a milk-derived amphiphilic protein, was selected as a promising material for wound dressings because of its anti-inflammatory activity and its ability to promote cell adhesion and proliferation, addressing critical needs in EB management. In parallel, aggregation-induced emission photosensitizers (AIE PSs) have been introduced as protective barrier coatings for wound treatments, since they offer low toxicity and its antibacterial mechanism involves reactive oxygen species (ROS) generation under visible light. Integrating an AIE PS coating onto the outer surface of casein/PVA nanofibrous dressings presents a promising strategy for managing chronic wounds and preventing bacterial infections in EB patients. Electrospinning was selected for its capacity to produce highly porous, and to mimic extracellular matrix (ECM) structures that encourage epithelial cell growth. The optimization of the polymer solution properties revealed that increasing viscosity and conductivity through casein incorporation improved uniformity and electrospinnability of the nanofibers. A multi-nozzle electrospinning setup was employed to fabricate a multilayer construct, enhancing mat thickness and surface porosity. The optimal 40:60 casein/PVA ratio produced in a sequential electrospun, presented some beads on its morphology, while glutaraldehyde crosslinking improved mechanical integrity and water resistance. Structural and surface characterization using SEM, FTIR, contact angle analysis, and fluorescence spectroscopy confirmed the successful formation of each layer. Swelling and in vitro tests for the nanofibrous mats demonstrated balanced exudate absorption and their moderate biodegradation in PBS. Surface modification via plasma polymerization created distinct wettability layers, with a hydrophobic PDMS outer coating serving as both a durable barrier and immobilization platform for AIE molecules. Upon illumination, AIE-coated samples exhibited S. aureus survival rates below 22.2% (15.8% at low concentration and 24.6% for MRSA), demonstrating significant photodynamic antibacterial efficacy. Overall, this study consisted on the design of a photoactive, multilayer wound dressing composed of casein/PVA nanofibers, plasma-modified surface coatings, and AIE photosensitizers to enhance both healing and antibacterial performance, representing a promising advance in next-generation wound care for fragile skin disorders.
Keywords: antibacterial wound dressing, casein nanofibers, electrospinning, aggregation-induced emission, photosensitizers, plasma polymerization, biocompatibility, wound healing, Epidermolysis Bullosa
Subject: Medical Biotechnology thesis
Thesis type: Masters
Completed: 2025
School: College of Medicine and Public Health
Supervisor: Youhong Tang