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Three-dimensional printing of bionic bone from Northwest China University of Technology is highly consistent with natural bone.

Post: 2019-04-26 15:21 View:2141

Recently, Professor Wang Yanen of Northwest Polytechnic University has made a breakthrough in the technology of 3D printing active bionic bone. The 3D printing active bionic bone developed by the team can achieve a high degree of consistency with the composition, structure and mechanical properties of natural bone. Animal in vivo experiments show that the bionic bone made by this technology can "develop" in vivo and allow autologous cells to grow in artificial bone. Finally, the artificial bone and natural bone grow well together and integrate into the internal environment of animals. At present, the team has mastered the technology of 3D printing bionic bone, cartilage and skin.

Bone defect is one of the most common diseases in orthopaedics. According to statistics, there are 7 people with serious disabilities caused by traffic accidents every minute in China, and there are about 10 million bone defect patients every year. Bone defect repair and reconstruction has been an international clinical problem. Traditional metal and polymer materials have some complications such as uncontrollable bionic structure, mismatched mechanical properties, poor biocompatibility, no developmental function, movement dislocation, wear and tear. Especially the prosthesis without biological activity can not develop in human body and can not be well fused with natural bone, so it needs second surgical repair.

In order to overcome this problem, scientists have made unremitting efforts. With the advent of 3D printing technology, bioceramics-based 3D printing bone has become the most ideal bone filling material. In recent years, foreign research institutes have developed 3D printing bioceramic bone implant medical devices. However, due to the use of acidic binder and functional gradient, the technology has not yet achieved complete degradation of ceramic bone, which will bring severe pain and other side effects to patients after implantation.

In 2004, Wang Yanen, who was also a doctoral student in Western Polytechnic University, set a goal of "developing 3D printing technology and equipment for artificial bone". As for the origin of this idea, Wang Yanen said frankly, "My mother's leg is disabled. At that time, I just wanted to cure her through my own efforts." Whenever he watches his mother who never acts, he always feels very sad.

Because the properties of traditional ceramic bone and natural bone are still quite different, it can not achieve good development in animals. In order to solve this problem, Wang Yanen started with printing materials. Hydroxyapatite is a universal human-like material in the world at present. However, how to bond powdered hydroxyapatite has always been a difficult problem. Acidic adhesives are used in foreign countries, which bring pain to implanted patients.

Wang Yanen said: "Maybe it's very simple for people who are engaged in chemistry to find a material that can bind hydroxyapatite, but once this problem is limited to 3D printing and application in humans, it becomes extremely complex."

Firstly, binders are mostly organic compounds with viscous and high surface tension. How to make them pass through printer nozzles with a diameter of only 20 micron (micron) approximate to that of hair has become the biggest problem. At the same time, the binder can also be accepted by animals and even human environment.

In order to find this suitable binder, Wang Yanen experimented with hundreds of different schemes, filling several large boxes with broken nozzles. Finally, he found an adhesive with a pH similar to that of an organism and good properties that would not clog the nozzle.

After years of exploration, Wang Yanen and his team have been able to scientifically match printing materials according to the skeletal properties of different individuals, such as hydroxyapatite, adhesives, cell fluid and protein liquid (growth factor), so as to print the most suitable artificial bionic bone for implanted individuals.

Natural bone is not only irregular in appearance, but also complex in internal structure, with different densities in different parts. It is extremely challenging to make artificial bone imitate natural bone in structure.

Wang Yanen invented the bionic bone 3D printing technology of active bioceramics, which solved the problem of "how to beat". Firstly, the laser is used to scan the printed object layer by layer to restore the macro and micro structure of the object. In the mixing material, powder printing link. Traditional 3D printing materials are single, uniform in density, single in powder and even in powder laying. It is difficult to meet the printing requirements of bionic bone. Wang Yanen not only developed a printing control system, but also conquered the key mechanical technology of printing, and realized bionic printing with complex structure, uneven density, composite powder and heterogeneous powder laying. This equipment's original atmospheric temperature piezoelectric ultra-micro atomization spraying technology breaks through the technical bottleneck of cell liquid, protein liquid spraying speed and spraying volume which is difficult to control precisely, and is at the international advanced level.

At the same time, the team has also established bionic bone and natural bone permeability testing equipment, which achieves a simple, rapid and objective assessment of bionic bone development ability. Animal experiments have shown that bionic bone can develop well after implantation into animal receptors, that is, autologous cells grow in artificial bone through the metabolism of receptors, and ultimately fully grow into autologous bone. No case of rejection reaction has been found in the joint animal experiment between Northwest Polytechnic University and Air Force Military Medical University of the Chinese People's Liberation Army (later referred to as Air Force Military Medical University).

"From the current experiment, we can not clearly indicate what side effects bionic bone will have in the recipient body. It may take a long period of follow-up study to find out. Wang Yanen's words are full of scientific rigour.

After testing, the 3-D printing active bionic bone is highly consistent with the natural bone composition, structure and mechanical properties. Compared with other similar 3D printing technologies, it has obvious technical advantages.

It is reported that the team has mastered bionic bone, cartilage and skin 3D printing technology. "Next step, we will continue to explore the stable printing technology of sweat glands, hair follicles, sebaceous glands and other structures in the dermis, so as to be very close to the natural skin." Team member Wei Qinghua said. At present, the healing time of bionic skin is 25% shorter than that of autologous skin in the implantation test of 3D printing rabbit skin.

Source:http://sh.qihoo.com