PolyU Develops Novel Self-fitting Scaffold for Bone Regeneration - Seite 2

The self-fitting scaffold possesses a highly porous structure with interconnected pores to allow cells migration and formation of new tissues. The average pore size of the scaffold is 670 μm (diameter of a human hair is around 100 μm), which is close to that of trabecular bone (the inner layer of bone) and thus mimics the actual in vivo microenvironment. The optimal structure of the scaffold is around 60% of space voids.

The mechanical strength of the scaffold can neither be too low (may cause deformation or crash) nor too high (may reduce the density of surrounding bone tissue). The compressive strength of the PolyU developed self-fitting scaffold is designed at 13.6MPa (Megapascal), which is comparable to that of trabecular bone. Laboratory tests also show that the self-fitting scaffold is biocompatible and has no cytotoxicity.

Animal study on bone regeneration 

"Our research team further examined the performance of the self-fitting scaffold in facilitating bone regeneration through a rabbit femoral defect study. The results show that our scaffold has overcome the disadvantages of traditional polymer scaffolds, and has great potential for bone regeneration," said Professor Hu.  

In the animal study, 18 rabbits with a femoral bone defect in each knee, making up a total of 36 lesions, were divided into experimental group and control group.

The bone defects of the rabbits in the experimental group were implanted with self-fitting scaffolds (with original size around 5% larger than the bone defects) compacted to around 50% of their original size. After triggering with 40°C saline, the scaffolds expanded from the compacted shape to fill the defect in 60 seconds. The bone defects in the control group were left unfilled.

Twelve weeks after the surgery, the experimental group displayed faster bone tissue ingrowth in volume. There was 46% of bone ingrowth, or the proportion of total defects being repaired. On the contrary, the control group had only 24%.

The self-fitting scaffold has been proved inducing the formation of osteoblasts and blood vessels, which are responsible for the synthesis of bone tissue. In the experimental group, 12 weeks after the surgery, the number of neovascular buds grew on the scaffolds was 4 times of that in the control group. Moreover, 5% of bone surface was covered by osteoblasts in the experimental group whereas the control group recorded almost no osteoblast.

In conclusion, the novel shape memory scaffold developed by PolyU has the advantages of:

• being implanted via minimally invasive operation;
• self-adaption and self-fitting;
• optimal structure for bone remodeling;
• full biocompatibility; and
• optimal mechanical properties.

Press Contact

Professor Hu Jinlian
Institute of Textiles and Clothing
Telephone: +(852)-2766-6437
Email: [e-mail]

Video:
https://1drv.ms/v/s!An7L4hj0BAmegWEqnbMaAD7Zxrrd

^[1]  Cheung, C. L., Ang S. B., Chadha M., Chow S. L., Chung Y. S., Hew F. L., Jaisamrarn U., Ng H., Takeuchi Y., Wu C. H., Xia W., Yu J., Fujiwa S. (2018). An updated hip fracture projection in Asia: The Asian Federation of Osteoporosis Societies study, Osteoporosis and Sarcopenia (4) 1, 16. doi.org/10.1016/j.afos.2018.03.003

^[2] Tests were conducted on scaffolds made with 1%, 3%, 5%, 7% of HA nano-particles in content. The figures cited in this press release are referring to scaffold with 7% HA nano-particles.