Page 146 - Tailoring Electrospinning Techniques for Regenerative Medicine - Marc Simonet

CHAPTER 7
air. Sca olds produced with this simple and straightforward method enable cell infiltration with fibers of submicrometer diameter (chapter 4). Additionally, we showed in chapter 4 that with LTE- spinning it is possible to tailor the void space and mechanical properties of the electrospun sca old towards physiological ranges of so tissue. Ultimately, an electrospun sca old has to be functional inside the body. In chapter 6 we described the path starting from a polymer to a short term functional in-situ heart valve sca old. While showing how crucial an appropriate sca old degradation profile and adherent degradation tests would be in the development process of such a sca old, we could successfully demonstrate for the first time the functionality of a purely electrospun sca old implant valve replacement. These findings were further pursued, recently leading to the first clinical trial where multiple pediatric patients received an electrospun pulmonary heart valve replacement electrospun by the company Xeltis.m
Taken together, this thesis has provided solutions and a proof of concept study of added value to the tissue engineering field utilizing electrospinning:
- A stable electrospinning environment makes the electrospinning results reproducible.
- Active control over the relative humidity allows a selective adjustment of the fiber morphology.
- The invented low-temperate electrospinning technique facilitates cell ingrowth also for submicrometer fibrous sca olds.
- In a proof of concept study, electrospun sca olds showed for the first time their potential in an in-situ heart valve tissue engineering procedure.
7.2 Electrospinning considerations and limitations
7.2.1 Combining sca old demands for tissue engineering
The electrospinning technique o ers solutions to comply with the sca old demands mentioned in chapter 1. But certain general challenges still have to be faced. For example:
- The thinner the required fiber diameter the bigger the challenges to comply with the demands.
- The biggest electrospinning challenges are found when combining di erent demands into one sca old.
For example, although highly aligned fibers can be produced with any fiber diameter, maintaining the fiber alignment while increasing the sca old thickness is still a big challenge. To our best knowledge this has not yet been achieved using nanofibers. The reasons for this are not yet fully
m http://www.xeltis.com/news/first-heart-valve-enables-cardiovascular-restoration-successfully-implanted-three-patients-xplore-clinical-trial/ 144