HONG KONG, August 15, 2018 /PRNewswire/ — A group of researchers from the Hong Kong Polytechnic University (PolyU) in close collaboration with Sichuan University have successfully designed and manufactured a novel bone scaffold that can be safely implanted into bone defects, induce bone-regeneration, and enhance the recovery of bone injuries and fractures.

Bone-fracturing is becoming an increasing global health concern, particularly in ageing societies. Therefore, enhancing bone-grafting methods and streamlining the induction of bone-regeneration can relieve patients from suffering and decrease the overall health-expenditure for society.

A recent study revealed that in Hong Kong alone the annual number of new cases of osteoporosis-related hip-fractures, currently 9,590, will triple by 2050. Malaysia and Singapore are facing a 3.5-fold increase.

In spite of the innate regenerative capacity of the bone, bone-grafting surgeries (both autografts and allografts) are often required to achieve bone-regeneration after severe fractures or procedures, such as the resection of bone tumours.

The self-fitting scaffold by the PolyU researchers led by Professor Hu Jinlian, Dr Xie Ruiqi from the Institute of Textiles and Clothes, and Dr Guo Xia from the Division of Rehabilitation Sciences, is made of made of polyurethane shape memory foam and hydroxyapatite (the principal mineral element of bone tissue) nanoparticles. The product compacts at 0°C and for injection into the bone. Once injected, the original shape can be completely recovered by triggering it with 40°C saline, a temperature matching that of the human body.

The novel scaffold fulfils two major requirements; it can act as a mould to achieve speedy tissue regeneration and that it can be utilised during a minimally invasive surgery, thus reducing the duration of hospitalisation and risk of secondary infections.

Study evidence

The scaffold was tested in an animal trial, including 18 rabbits with bilateral femoral bone defects. The resulting 36 lesions were then divided into an experimental group in which lesions were filled with the novel scaffold and a control group which was left unfilled.

“The results [of the animal studies] show that our scaffold has overcome the disadvantages of regular polymer scaffolds, and has excellent prospective for bone regeneration,”

~Professor Hu Jinlian

The invention showed to increase the formation of osteoblasts and blood vessels. In the rabbit study, at 12 weeks after the surgery, bone tissue ingrowth in volume was faster in the experimental group (46%) when compared to the control group (24%). Moreover, the experimental group displayed a 4-fold number of neovascular buds growing on the scaffolds when compared to the control group. In the experimental group, 5% of the bone surface was covered by osteoblasts, whereas in the control group, osteoblasts were nearly unseen.

Features of PolyU’s bone scaffold

The novel scaffold developed of shape memory polyurethane foam (a sort of plastic material) and hydroxyapatite (HA) nano-particles is characterized by its outstanding self-fitting effect. It has a porous structure with interconnected pores which allow for cell migration and formation of new tissues. The material’s mechanical strength is similar to the trabecular bone.

References

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 trial, Osteoporosis and Sarcopenia (four) 1, 16. doi.org/10.1016/j.afos.2018.03.003

2. Tests have been performed on scaffolds produced with 1%, three%, five%, 7% of HA nano-particles in content material. The figures cited in this press release are referring to scaffold with 7% HA nanoparticles.