In a small step forward in biomedical research, a doctoral thesis from the University of Borås has investigated how a special type of bioplastic, polyhydroxyalkanoates (PHA), produced by bacteria, can be used to support bone healing in cases of large bone defects.
THE PROCESS: The biggest challenge—processing PHA into fibres, with similar strength to bone, with the available equipment—was done by melting the plastic and pressing it through a hole, similar to making spaghetti. The produced fibres were then tested with bone cells to see if the cells could survive on the material.
- Additionally, the researcher, Sabrina Kopf, PhD in Polymer Technology from the Borås’ Faculty of Textiles, Engineering and Business, was able to produce simple knitted and woven textile structures from these fibres.
- The bone cells adhered to the material's surface and appeared healthy, which is a good sign.
WHAT ARE PHAs: PHAs are a group of thermoplastic, biobased and biodegradable polyesters, showing promising potential for the use in medical textiles. This is because of their favourable degradation properties, which are considered superior to those of currently used biomaterials. However, PHAs like poly(3-hydroxybutyrate) entail challenges regarding their melt processability, due to the closeness of their thermal degradation temperature to the melting temperature and secondary crystallisation, which results in material embrittlement.
- The fibres can also be used in other textile applications and contribute in all aspects where textiles are involved.
- Besides, PHA and its products are biodegradable and have no negative impact on the environment.
- PHA fibres are also beneficial for health and can be produced from residuals and degrade in all types of environments without remaining as microplastics. This makes them a sustainable option for the future.
LOOKING AHEAD: Kopf will soon start as a researcher in melt spinning at RISE in the fibres development department so that she can work with the same technology used in her thesis.
THE CONTEXT: Bone is, after blood, the second most transplanted tissue in the world, indicating a significant need for bone replacement materials.
- Today, bone from the patient's own body is often used, meaning that bone is taken from, for example, the pelvis and transplanted to the damaged area in the body. This limits the amount of bone available. Additionally, the risk of complications at the donation site is high. Using synthetic materials like PHA fibres could be a solution to this problem.
- Medical textiles are among the fastest growing sectors in the textile industry, with rapid progression especially in wound healing and implantable devices. Considerable attention is paid to the development of new fibre-based absorbable polymer implants because they reduce or eliminate the need for additional surgery to remove implanted structures.
- For bioabsorbable implants, the rate, mechanism and products of degradation must be carefully controlled to ensure the material functions as intended. Specifically, the degradation rates of the product should ideally be in alignment with the formation of new tissue, and the degradation products must be non-toxic and have minimal interference with the surrounding tissue and the body.
WHAT THEY SAID:
The results of my project are a small step forward in biomedical research and can inspire other researchers to explore the potential of textiles in medical applications. Being able to produce fibres from PHA benefits not only the healthcare sector, even though that was the approach of my thesis. The fibres can also be used in other textile applications and contribute in all aspects where textiles are involved in the UN's sustainable development goals, as PHA and its products are biodegradable and have no negative impact on the environment.
— Sabrina Kopf
Phd researcher
University of Boras
