A 3D Printed Zinc Scaffold Could Treat Bone Defects

Bone defects can be congenital or accident-related and require different treatment approaches depending on the cause. One possible method of healing is a 3D-printed zinc scaffold, which is being developed by Chinese experts from Beihang University, Renji Hospital, Shanghai Jiao Tong University, Tsinghua University and Peking University to treat large bone defects. The project is supported by the Chinese company Bright Laser Technologies (BLT) with its 3D printing machines and systems.

These 3D-printed, porous zinc structures offer an innovative approach to repairing bone defects through bone regeneration. However, a major challenge to date has been the rapid degradation of the zinc structures, which has led to toxicity. For this reason, the composition of the alloy, the surface structure and the pore geometry of the scaffolds have now been optimized.

The degradation behavior of the 3D printed zinc scaffolds in rat femur after three days and three months (image credits: Li, S., Yang, H., Qu, X. et al. Multiscale architecture design of 3D printed biodegradable Zn-based porous scaffolds for immunomodulatory osteogenesis.Nat Commun 15, 3131, 2024.)

In the last three years, the researchers have worked on developing novel, biodegradable zinc alloys (Zn-Li) that can be used to 3D print these frameworks. The Zn-Li alloys (0.8% Li by weight) offer mechanical properties and a good balance between strength, plasticity and corrosion behavior. The frameworks were manufactured using BLT’s L-PBF system, which enables precise designs and complex structures.

After 3D printing, various surface treatments such as ultrasonic treatment, acid etching and electrochemical polishing were performed to optimize surface roughness and promote cell interaction. These treatments resulted in a targeted micro-patterning of the surface that improves both cell adhesion and cell spreading, which is important for bone regeneration.

The design of 3D-printed, biodegradable and porous zinc-based scaffolds (image credits: Li, S., Yang, H., Qu, X. et al. Multiscale architecture design of 3D printed biodegradable zinc-based porous scaffolds for immunomodulatory osteogenesis. Nat Commun 15, 3131, 2024)

In addition, the special surface structures promote interaction with macrophages, i.e. white blood cells, and can improve the immune response, the reaction of the immune system to potentially harmful organisms, which ultimately supports bone regeneration. Furthermore, the 3D-printed zinc scaffold shows controlled degradation in the body, which is associated with bone regeneration. This property is crucial to create an optimal environment for the regeneration and integration of the implant.

Overall, the use of 3D-printed scaffolds leads to an efficient improvement in bone regeneration compared to conventional implants, as the structural and chemical properties of the scaffolds promote new bone formation. The use of 3D printing to produce Zn-Li scaffolds offers great potential, allowing precise control over the structure and porosity of the implants, which is crucial for bone regeneration. You can find out more about the research HERE.

Surface morphology and properties of Zn-0.8Li scaffold after ultrasonic treatment, acid etching and electrochemical (EC) polishing (image credits: Li, S., Yang, H., Qu, X. et al. Multiscale architecture design of 3D printed biodegradable Zn-based porous scaffolds for immunomodulatory osteogenesis.Nat Commun 15, 3131, 2024.)

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