Doctoral defence: Georg-Marten Lanno “Development of novel antibacterial drug delivery systems as wound scaffolds using electrospinning technology”

On 16 December at 15:15 Georg-Marten Lanno  will defend his doctoral thesis “Development of novel antibacterial drug delivery systems as wound scaffolds using electrospinning technology” for obtaining the degree of Doctor of Philosophy (in Biomedical Technology).

Supervisors:
Professor Karin Kogermann, University of Tartu
Professor Tanel Tenson, University of Tartu
Research Fellow Marta Putrinš, University of Tartu

Opponent:
Professor Romána Zelkó, Semmelweis University (Hungary)

Summary
Wound treatment is a worldwide problem with annually increasing costs and insufficient treatment options. There is always contamination related to wounds which increases the risk for the development of infection. Therefore the main treatment strategy has been to restore the homeostasis at the wound site as well as control the bacterial load. The problem arises when the patient's medical condition (for example diabetes) inhibits the native immune response causing failed and long-lasting treatment. The administration of antibacterial drugs is a vital part of chronic wound and infection treatment strategy. Topical treatment with antibiotics (conventional drug formulations such as gels, creams) is frequently used but its efficiency is still uncertain. Therefore novel drug delivery research is focused on finding the site-specific drug delivery systems (DDS) with enhanced antibacterial properties.

Electrospinning (ES) is a straightforward method for the production of polymeric fibers with specific features: controlled surface morphology, large specific surface area, tunable porosity and relatively simple incorporation of drugs giving them potential to be used as DDS. ES scaffolds have potential in wound healing due to having structure similar to the extracellular matrix,  which offers superior absorption of the wound exudate as well as enhanced gas exchange properties. Furthermore, the scaffolds have suitable mechanical properties which can be designed to ease application and offer suitable surface for cell growth in charge of native wound healing. When developing antibacterial scaffold for wound infection treatment the bacterial/scaffold interactions have to be addressed. Ideally the scaffold should inhibit the bacterial growth at the wound site and protect the wound from further contamination.

In the present thesis ES was used to prepare antibacterial  fiber scaffolds for wound healing applications. It was seen that the combination of suitable solvent systems, and environmental parameters were vital in order to produce antibacterial drug containing polymer based fibers with surface porosity. The solvent systems had an effect on the morphology, structure, mechanical and drug release properties of the scaffolds. The structural differences also affected the behaviour of cells (bacterial and eukaryotic) on scaffolds  . Fibers with surface porosity supported fibroblast attachment and growth as well as provided the best antibiofilm activity against E. coli. Another part of the thesis was to develop zein based antibacterial fiber scaffolds. Coaxial ES method together with plasticisers were used in order to develop zein-based core-shell structured scaffolds. The scaffolds were also characterised and differences were seen compared to the polycaprolactone-based scaffolds.