Regenerative medicine is looking for structures to support the self-healing capacities of the human body. The implant scaffolds need to induce cell proliferation and promote reformation of the tissue. To create high-performance implants, adjustable degradation rates of the biomaterials, interconnected pores and functional surfaces are important. Due to their unique characteristics, chitosans are perfectly suitable to fulfill those requirements of regenerative medizin, due to their unique characteristics. In the following, we want to present you two highly interesting studies from research in this field.
In silico modeling of structural and porosity properties of additive manufactured implants for regenerative medicine
Bruenler R., Aibibu D., Woeltje M. et al. Materials Science and Engineering C 76 810–817, July 2017
Creation of customized implants for regeneration of various tissues using fibers is a promising research field in medical technology. Researchers from Dresden (Germany) applied the Net-Shape-Nonwoven (NSN) technology to manufacture chitosan scaffolds. For preparation of scaffolds, chitosan with medium molecular weight (200-300kDa) and a deacetylation degree of 90% by Heppe Medical Chitosan GmbH was applied. Chitosan fibers with diameters with 20 µm, 30 µm and 40 µm were spun wet and cut into short fibers with length of 0.5, 1.0 and 2.0 mm. Chitosan NSN-structures were characterized by scanning electron microscopy. Additionally fiber-based scaffolds were modeled based on NSN technology, to simulate pore-sizes and pore-size distribution. Modeled and real NSN structures were compared.
- Pore-size and porosity of scaffolds can be predicted
- Mean pore-sizes of modeled NSN scaffolds corresponds to the real structure
Conclusion: Process characteristics of Net-Shape-Nonwoven technology can be modeled and match with actual properties of chitosan-based scaffolds. In silico modeling allows to reduce cost and time for extensive testing during the development process. The NSN technology is a promising tool to create chitosan scaffolds with desired properties for tissue regeneration.
Chitosan degradation products facilitate peripheral nerve regeneration by improving macrophage-constructed microenvironments
Zhao Y., Wang Y., Gong J. et al. Biomaterials. 134:64-77. July 2017. doi: 10.1016/j.biomaterials.2017.02.026.
The biocompatible chitosan has numerous benefits as scaffold material for nerve regeneration. Furthermore, the degradation product chitooligosaccharides (COS) promotes cell proliferation and prevents cell apoptosis. In the study, injured sciatic nerves in rats were bridged with COS-filled silicon tubes. Cell proliferation and migration as well as gene expression were determined.
- COS promotes Schwann cell proliferation
- COS downregulates miR-327 in Schwann cells and stimulates CCL2 expression
- CCL2 induces cytokine expression and macrophage migration at injury site
- Reconstruction of microenvironment
- Support of nerve regeneration
Conclusion: COS-filled silicon tubes as bridge for injured sciatic nerves in rats, recruited pro-inflammatory cytokines and macrophage. Therefore, Chitosan-based grafts are promising tools for peripheral nerve regeneration.