Despite intensive research, hydrogels currently available for tissue repair in the musculoskeletal system are unable to meet the mechanical, as well as the biological, requirements for successful outcomes. With an international team of researchers under the leadership of UMC Utrecht , we developed a material that could help cartilage tissue in joints to heal using 3D printing techniques. This may facilitate the treatment of larger joint defects than can be treated with current techniques. Moreover, thanks to 3D printing technology, it would be possible to reconstruct the joint’s original shape.
This discovery may facilitate the treatment of larger joint defects than can be treated with current techniques
We used materials called hydrogels, which are networks of polymers that can absorb large quantities of fluid. Some examples of hydrogels include winegums, pudding and soft contact lenses. In regenerative medicine, hydrogels can serve as carriers for cells to restore joint cartilage. Using 3D printing techniques, we were able to ‘print’ a network of thin fibres, with which they then reinforced the gel. The new composite material displayed properties similar to joint cartilage. At the moment, a number of Dutch hospitals are successfully utilising cell therapy to repair cartilage damage. But there are still limitations to the size and shape of the cartilage defects that can be repaired. Our reinforced hydrogels are sturdier and more elastic than the currently applied cell carriers, and we may eventually be able to use them to restore larger areas of the joint. In addition, with 3D printers it is possible to reconstruct the specific shape of the defect, as well as the contours of the joint. At the moment, we are studying the recovery of larger joint defects using these reinforced hydrogels and examine the quality of the newly formed cartilage.
We reinforce soft hydrogels with highly organized, high-porosity microfibre networks that are 3D-printed with a technique termed as melt electrospinning writing. They show that the stiffness of the gel/scaffold composites increases synergistically (up to 54-fold), compared with hydrogels or microfibre scaffolds alone. Modelling affirms that reinforcement with defined microscale structures is applicable to numerous hydrogels. The stiffness and elasticity of the composites approach that of articular cartilage tissue. Human chondrocytes embedded in the composites are viable, retain their round morphology and are responsive to an in vitro physiological loading regime in terms of gene expression and matrix production. The current approach of reinforcing hydrogels with 3D-printed microfibres offers a fundament for producing tissue constructs with biological and mechanical compatibility.
This discovery may facilitate the treatment of larger joint defects than can be treated with current techniques.
Dr. ir. Jos Malda is an associate professor at Utrecht University at the department of equine sciences and an assistant professor at the University Medical Centre Utrecht (UMC) at the department of Orthopaedics. His research group focuses on biofabrication and biomaterials design, in particular for the regeneration of (osteo) chondral defects. He is also president of the International Society for Biofabrication (ISBF), member of the General Board of the International Cartilage Repair Society (ICRS), co-chair of the international Conference on Biofabrication 2015 and head of the Utrecht Biofabrication Facility.
Joint regeneration , biofabrication, biomaterial development, bioreactors, extracelular matrix-derived scaffolds, nutrient limitation, equine muscoskeletal biology