Image Source: UConn
Musculoskeletal injuries can take many weeks or months to heal and in severe cases when there has been volumetric muscle loss there are no reconstructive surgery techniques that are adequate.
One exciting area of research is the use of 3D printing. 3D bioprinters can be used to print biological scaffolds that support tissue regeneration. Instead of ink, the printers use bioinks, which are gelatin-based hydrogels. These printers can be used to create fibrillar scaffolds to support cell growth and tissue regeneration. These scaffolds can help to speed up recovery in areas where there has been volumetric muscle loss; however, there is a problem. In order to create a suitable scaffold, 3D imaging studies need to be performed to be able to render computer models to allow the scaffolds to be printed. The process takes time, so it does not support immediate reconstructive interventions in patients with post-traumatic injuries. For that to happen, scaffolds would need to be printed directly into the location where they are required, and that would require a handheld 3D printer.
A biomedical scientist at the University of Connecticut School of Dental Medicine have developed such a device. The device is robust, can be held comfortably in the hand, and allows scaffolds to be printed in situ with precision.
The 3D printer has been used to fill cavities at a site of injury with fibrillar scaffolds that exactly match the geometry of the injury site. The fibers in the scaffold are crosslinked and provide support and closely resemble the architecture of native tissue. They also mimic the properties of existing tissues and support cell growth and tissue regeneration. By using these scaffolds, there is no need for suturing.
The researchers tested the adhesiveness of the bioink to skeletal muscle ex vivo, and report that delivery of cells was successful in vitro. The researchers then tested the device by printing an acellular scaffold in mice with volumetric muscle loss in vivo. There was proper adhesion to surrounding skeletal muscle and the scaffold promoted remnant skeletal muscle hypertrophy.
The handheld bioprinter was developed by Dr. Ali Tamayol, an associate professor at the UConn School of Dental Medicine’s biomedical engineering department. Dr. Indranil Sinha, a plastic surgeon at Harvard University worked with Dr. Tamayol on the project.
“A customisable, printed gel establishes the foundation for a new treatment paradigm can improve the care of our trauma patients,” said Dr. Sinha. A patent for the new technology for the treatment of musculoskeletal injuries has been filed by Dr. Tamayol and Dr. Sinha.
You can read more about the technology in the paper – In Situ Printing of Adhesive Hydrogel Scaffolds for the Treatment of Skeletal Muscle Injuries – which was recently published in the American Chemical Society Journal. DOI: 10.1021/acsabm.9b01176