3D-printed artificial tissues to help heal damaged bones and cartilage
Scientists have moved a step closer to one day creating 3D-printed artificial tissues to help heal damaged bones and cartilage. Researchers at Rice University in Texas and the University of Maryland have created scaffolds, or latticed structures, that replicate some of the characteristics of osteochondral tissue – hard bone beneath a compressible layer of cartilage found at the ends of long bones.
Athletes are particularly susceptible to knee, ankle and elbow injuries in which such bones may crack or lose small pieces. These injuries can be career-ending and, as well as being painful, can lead to severe arthritis.
The gradient nature of osteochondral tissue as it transitions from cartilage into bone, as well as its porosity, have made it difficult to reproduce in the lab. Researchers in Rice University’s Biomaterials Laboratory printed a structure made of a polymer to mimic the former and a ceramic to mimic the latter. The porous nature of the structure would allow the patient’s own blood vessels to grow into it from the bone, instead of doctors having to build vessels as well.
In compressive tests, the researchers found their structure to be mechanically comparable to real bone. But at the moment, the idea is just a proof of concept. For it to be viable, scientists will need to work out how to print an implant that perfectly fits a patient and can be accommodated by their bone and cartilage.
The researchers published their results last month in the international peer-reviewed biomaterials journal, Acta Biomaterialia. They wrote: “The results of this study demonstrate that this technique may serve as a template for future advances in 3D printing technology that may better address the complexity in such heterogeneous tissues.”
The National Institute of Health – the US national medical research agency – and the RegenMed Development Organization, a US non-profit which works to speed up the availability of regenerative medicine, supported the research, which adds to a growing body of work on the possibility of 3D-printed bone implants. Some studies have involved 3D printing at the point of injury.
Last August, scientists and surgeons at New York University’s School of Medicine and College of Dentistry used 3D-printed scaffolds to regenerate small holes in the skulls of mice and missing pieces of rabbits’ limbs and jaws up to 1.2 cm long. The implants mimicked the shape of damaged bones and were made from a gel containing suspended particles of calcium phosphate, an essential component of bones, so they could be easily broken down by the body, dissolving as the bones healed. They were also coated in dipyridamole, a blood thinner which speeds up bone formation. The study was published in the Journal of Tissue Engineering and Regenerative Medicine. Senior investigator and biomedical engineer, Paulo Coelho, said: “These results move us closer to clinical trials and potential bone implants for children living with skull deformations since birth, as well as veterans seeking to repair damaged limbs.”
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