Korean researchers have developed a technique for producing cancellous and cortical bone implants. Previous studies have focused on producing cancellous bone, which has a spongy, honeycombed structure. However, artificial bones for practical applications must also imitate cortical bone, the hard, strong tissue found on the outer layers of bone. By mimicking natural bone, it is hoped the implant material will better complement the natural regeneration process. The research by Yang-Hee Kim and Byong-Taek Lee from the Department of Biomedical Engineering and Materials, School of Medicine, at Soonchunhyang University is published in the current issue of Science and Technology of Advanced Material (STAM).
Cortical bone is less porous than cancellous bone, but contains canals through which the nutrients for bone formation flow. By developing a process to imitate this canal structure, the researchers have made significant advances in the fabrication of artificial bones, notes the National Institute for Materials Science (NIMS) in a press release.
The technology involves wrapping hydroxyapatite-loaded PMMA-PCL around 0.3-mm-diam steel wires by means of electrospinning. The biopolymer bundles cover a scaffold of cancellous bone structure, made by the standard sponge replica method out of zirconia (ZrO2) and biphasic calcium phosphate (BCP). Removal of the steel wires reveals an interconnected structure that mimics small human bones.
The resulting structure is characterized by high strength and approximately 70% porosity, similar to natural bone. Although tests have shown the material to be biocompatible, further in vitro and in vivo research is needed to fully evaluate its biological properties.
An ageing population makes bone loss and fractures a major worldwide problem and stimulates bone regeneration research. Biomimetic approaches to making artificial implants have attracted much attention, but the dependence of the healing process on interaction with the implant material requires close mimicry of the architecture of natural bone. This paper marks a significant advance in the development of materials and processing technology for the fabrication of artificial bone structures, according to NIMS.
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