Page 12 - Tailoring Electrospinning Techniques for Regenerative Medicine - Marc Simonet

engineering applications, control of the spatial fiber distance (SFD), o en also referred to as pore size, is crucial for cell attachment, proliferation and migration. Based on a range of LTE spun sca olds made of poly(lactic acid) and poly(ε-caprolactone) (PCL), it was found that the fiber sti ness o ered considerable control on the resulting sca old void spaces. In addition to adjustable void space, other advantages of this process are its straightforward design, the fact that it does not require the use of additional chemicals and it o ers the possibility to create three-dimensional structures with any material and, as long as the relative humidity is kept above 30%, its robust process design.
The second part of the thesis focuses on the application and functionality of electrospun sca olds for in-situ heart valve tissue engineering. For this tissue engineering approach, sca olds with an appropriate biomechanical and spatial structure are required to assure immediate functionality and durability, and to enable cellular infiltration. A PCL-bisurea-based polymer represents a promising material to capture these features. It is fatigue resistant for more than 3 million cycles at 10% elongation. The corresponding electrospun valves, formed from an electrospun tube, showed a good hemodynamic performance in a pulse duplicator at “pulmonary plus” (50/25 mmHg) conditions for 20 hours. Furthermore, these valves showed immediate functionality in a sheep model as well as cellular infiltration with subsequent
collagen production up to 5 weeks. However, due to too fast degradation of the sca old, the valves failed a er 4 to 5 weeks. Despite the required improvement of the degradation characteristics of the polymeric valve, this shows that in-situ tissue engineering of heart valves by electrospun polymeric sca olds is a promising approach towards a living heart valve prosthesis
In conclusion, we could establish that stable environmental conditions vastly improve the reproducibility of the electrospinning technique while new tools were demonstrated to mimic the ECM more closely and improve the sca old functionality. Furthermore, this thesis shows that electrospun sca olds have promising potential even for use in highly demanding in-situ tissue engineering applications.
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