Fixing bones with a silicone gun: the technique Koreans want to implement

A modified silicone or glue gun for performing bone grafts directly onto fractures and defects during surgery. It sounds like fiction, but it's already a reality, although it can't yet be applied to humans. The results of this research, conducted on rabbits,were published this Friday in the journal Device , part of the Cell Press group.

"Our goal was to create a portable on-site printing system that could be easily equipped and used in clinical settings. To do this, we used a glue gun-type printing device," Jung Seung Lee , senior author and professor of biomedical engineering at Sungkyunkwan University in Seoul , told El Confidencial.

He also explains that the material they use, which is equivalent to the hot silicone bars inserted into these guns, can be deposited directly onto bone defects of various geometries. "Thanks to this printing system, we can save time and money on the complex procedures required to manufacture bone grafts using conventional 3D printing . Furthermore, by adding biofunctional molecules such as growth factors, antibiotics, and drugs, we can turn this system into a multifunctional bone graft printing system."

The study also notes that bone implants have historically been made from metal or donor bone. However, the most up-to-date method of producing them is 3D printing, but the process is not easy, as, in cases of irregular bone fractures , these implants must be designed and manufactured before surgery. "We are trying to address some of the limitations of current technologies," Lee explains.

The material inserted into the gun is a filament composed of two main components: hydroxyapatite (HA), a characteristic of natural bone that promotes healing, and polycaprolactone (PCL), a biocompatible thermoplastic . PCL can be liquefied at temperatures up to 60°C and, when applied with this device, prevents tissue damage during surgical application while adapting to the irregular grooves of the fractured bone. "By adjusting the ratio of HA and PCL within the filament, the hardness and strength of the grafts can be customized to suit different anatomical needs," the statement says.

Lee also points out that thanks to its compact design, the surgeon can adjust the direction , angle, and depth of the impression in real time during surgery. "We have demonstrated that this process is completed in a matter of minutes. This represents a significant advantage in terms of reducing surgical time and improving the efficiency of the procedure," he explains.

Regarding the other properties of this technology, the researchers incorporated vancomycin and gentamicin , two antibacterial compounds, into the gun's refills. "Both in Petri dish culture and in liquid medium, it successfully inhibited the growth of Escherichia coli and Staphylococcus aureus , two common bacteria prone to causing postoperative infections. The drugs are released slowly and can diffuse directly into the surgical site for several weeks," he says.

"We have confirmed the therapeutic potential of these technologies using a rabbit model, but their translational potential and long-term safety require further evaluation using a large animal model. Furthermore, we continue to research and examine the functionalities of this system in terms of anti-infection and detection for versatile applications," the researcher notes.

The goal is for the material to biologically integrate with the surrounding bone tissue and gradually degrade over time to be replaced by newly formed bone. The scientists' next goal is to further optimize the antibacterial potential and prepare the procedure for human trials. "We don't know how long it will take to reach clinical application; we will continue to investigate," Lee concludes.