A team of biomedical engineers and dentists have created a new hydrogel that promotes the regeneration and repair of bone defects without the side effects associated with techniques currently being evaluated in experimental treatments.
The new hydrogel was tested in a mouse model and was shown to induce the migration of stem cells to the site of injection which accelerated the rate at which bone defects healed.
Hydrogels have shown great promise in regenerative medicine, although there have been considerable challenges developing hydrogels that promote healing to a sufficient degree to make them suitable for clinical applications.
Hydrogels consist of a three-dimensional network of polymer chains that absorb water like living tissue. Cells can be housed inside the pores between the polymer chains, allowing those cells to be delivered directly to the site where they are needed.
However, the hydrogels currently being tested have tiny pores which limits the expansion of cells and their survival time. Their use in tissue regeneration is therefore limited. Now researchers at the University of California Los Angeles (UCLA) have developed a new type of hydrogel that has a much more porous structure and can house more cells, give them greater space to expand, and increases their survival time. That makes them much better at promoting the formation of new bone.
The researchers combined a new biomaterial with clay, which is biologically compatible, easy to obtain, and is not known to cause any negative side effects. The biomaterial and clay were layered using a process called intercalation chemistry. Photo-induction was then used to turn the material into a gel that could be injected, in this case, into a mouse with a non-healing skull defect.
Six weeks following treatment, the mouse model showed significant healing at the site of the defect, which was due to the migration of naturally occurring stem cells to the injection site. This method of encouraging bone regeneration is less invasive that surgery and avoids the associated complications.
“This research will help us develop the next generation of hydrogel systems with high porosity and could greatly improve current bone graft materials,” said Min Lee, lead author of the study and professor of biomaterials science at the UCLA School of Dentistry. “Our nanocomposite hydrogel system will be useful for many applications, including therapeutic delivery, cell carriers and tissue engineering.”
The researchers are now investigating how the composition of the hydrogels affects the migration of stem cells and the formation of blood vessels.
The research is detailed in the paper – Microporous methacrylated glycol chitosan-montmorillonite nanocomposite hydrogel for bone tissue engineering – which was recently published in the journal Nature Communications. DOI: 10.1038/s41467-019-11511-3