Researchers have developed a novel surgical tool, modeled after a glue gun, that can 3D print bone grafts directly onto fractures and defects during surgery. The innovation, described in the journal Device, has already been tested in rabbits and offers a faster, more precise way to create complex bone implants without prefabrication.
Moving Beyond Traditional Bone Implants
Traditionally, surgeons have relied on metal, donor bone, or prefabricated 3D-printed implants. However, in irregular bone breaks, these implants must be designed and shaped in advance, often requiring complex imaging and modeling. The new technology eliminates that step.
“Our proposed system enables real-time fabrication and application of scaffolds directly at the surgical site,” explains Jung Seung Lee, associate professor of biomedical engineering at Sungkyunkwan University. “This ensures accurate anatomical matching even in complex defects without preoperative preparation.”
How the Device Works
The tool uses a filament made of two key materials: hydroxyapatite (HA), a natural bone component that supports healing, and polycaprolactone (PCL), a biocompatible thermoplastic. PCL liquefies at about 60°C—low enough to avoid tissue damage while still allowing the graft to adapt to jagged bone surfaces.
By adjusting the ratio of HA to PCL, surgeons can customize the hardness and strength of the graft for different anatomical needs. Because the device is compact and manually operated, surgeons can also control the direction, angle, and depth of printing in real time, completing the process within minutes.
Built-In Infection Control
Since surgical implants often carry infection risks, the researchers embedded two antibiotics—vancomycin and gentamicin—into the filament. In lab tests, the scaffold successfully inhibited the growth of E. coli and Staphylococcus aureus, two bacteria frequently responsible for post-surgical infections.
Importantly, the scaffold releases the antibiotics slowly over several weeks. This localized drug delivery reduces systemic side effects, limits antibiotic resistance, and offers more direct protection against infection.
Promising Results in Animal Trials
As proof of concept, the team tested the device on rabbits with severe femoral bone fractures. After 12 weeks, the animals showed no signs of infection or necrosis. Compared to rabbits treated with conventional bone cement, those receiving the 3D-printed grafts displayed greater bone regeneration and superior outcomes in parameters like bone surface area, cortical thickness, and structural stability.
Lee emphasized that the scaffold not only integrates with surrounding bone tissue but also gradually degrades, allowing new bone to replace it naturally over time.
Next Steps Toward Clinical Use
As reported by medicalxpress, the researchers now aim to further enhance the antibacterial properties of the scaffold and prepare for human trials. However, they acknowledge the challenges ahead.
“Clinical adoption will require standardized manufacturing processes, validated sterilization methods, and preclinical studies in large animals to meet regulatory approval,” Lee notes. “If successful, we envision this approach becoming a practical, immediate solution for bone repair in operating rooms.”