In a significant development for bone healing technology, researchers have successfully identified a suitable material for their innovative healing gun. “We utilized a biocompatible thermoplastic known as polycaprolactone, combined with hydroxyapatite, as our foundational materials,” explained Lee, the lead researcher. Polycaprolactone is FDA-approved, designed to degrade within months post-implantation, while hydroxyapatite promotes the regeneration of bone tissue. After experimenting with different ratios of these components, the team achieved a formulation that is not only mechanically stable but also extrudes at a benign temperature of 60° Celsius and adheres well to bone.
The newly developed bone-healing bullets were subsequently tested on rabbits. Findings showed that rabbits with fractured femurs treated using Lee’s device displayed faster recovery compared to those treated with traditional bone cement, which is the current leading commercial option. Despite these promising results, further research is necessary before moving on to human trials.
Challenges Ahead
While the tests on rabbits highlighted the formation of new bone tissue around the implants created with the healing gun, a slow degradation rate of the material hindered complete restoration of the bone structure. To address this, Lee is considering the incorporation of antibiotics into the formulation. These additives would be gradually released from the implant to help combat infections.
Another concern is the ability of the implants to bear weight. Although rabbits serve as useful initial test subjects, their lighter size raises questions about the technology’s applicability to humans. “To better understand the implications for human use, we need to assess the long-term safety in larger animal models,” Lee noted.
Additionally, the operation of the healing gun demands a certain level of expertise. Extrusion-based 3D printers, similar to advanced hot glue guns, typically use guiding rods or rails to ensure precise positioning of the printing head. Even minor warping of these components can compromise accuracy. Achieving similar precision with a handheld device could prove challenging, even for experienced surgeons. “It is indeed a system that requires practice,” Lee acknowledged. “We might need to incorporate a guiding mechanism to enable precise positioning of the device’s head. This could pave the way for our next-generation bone printing technology.”
Device, 2025. DOI: 10.1016/j.device.2025.100873
