Bone defects are one of the most common diseases in orthopedic clinics. Every minute in China, there are 7 people with serious disabilities caused by traffic accidents, and there are about 10 million patients with bone defects every year. The repair and reconstruction of bone defects has always been an international clinical problem. Northwestern Polytechnical University, Prof. Wang Yanen team recently published a paper in the British “Polymer” (Polymer) magazine that they developed the 3D printing of active biomimetic bone can be “developed” in the organism, to achieve a high degree of consistency with the composition, structure, mechanical properties of natural bone, has been to the “” to fake”. To the extent that the fake is real”! Science and Technology Daily reporter recently in-depth Northwestern Polytechnical University to find out.

　　The most core technology lies in the “bionic”

　　“The traditional metal, polymer materials exist bionic structure is not controllable, mechanical properties do not match, poor biocompatibility, no developmental function, movement dislocation, wear and tear and other postoperative complications. Especially the prosthesis without biological activity cannot develop in the human body, cannot integrate well with natural bone, and requires secondary surgical repair.” Seeing the reporter, Prof. Wang Yan'en opened his mouth and said so frankly.

　　Wang Yanen team developed 3D printing bionic bone, the core technology lies in the “bionic”. Due to the traditional ceramic bone and natural bone performance is still a big difference, can not realize the good development in the animal body. In order to solve this problem, Wang Yanen first started from the printing material. Hydroxyapatite is currently the world's general humanoid bone material, however, how to bond the powdered hydroxyapatite has been a problem. Overseas, it is because of the use of acidic adhesives, which caused postoperative pain to the implanted person. Most adhesives are organic compounds with high viscosity and surface tension, so how to pass them through the printer's nozzle, which is only 20 microns in diameter and as thin as a hair, has become the biggest challenge. At the same time, the binder has to be acceptable to animals and even to the human environment. In order to find a suitable binder, Wang Yanen tested hundreds of different solutions, and filled several large boxes with broken nozzles. Finally, he found an adhesive with a pH similar to that of living organisms and good properties that would not clog the nozzles.

　　After years of exploration, Wang and his students have been able to use hydroxyapatite, adhesive, cellular fluid, protein fluid (growth factors), etc. in accordance with the nature of the bones of different individuals, the scientific proportion of the printing materials, so as to print the most suitable for the implanted individual artificial bionic bone.

　　Autologous Cells Growing in Artificial Bone

　　Natural bone is not only very irregular in appearance, but also has a complex internal structure with different densities in different parts. Trying to make artificial bone mimic natural bone structurally is extremely challenging. Wang Yanen invented the active bioceramic bone 3D printing technology, which solves the problem of “how to fight”.

　　In the proportioning of materials, powder printing, the traditional 3D printing of a single material, uniform density, single powder, uniform powder, it is difficult to meet the needs of biomimetic bone printing. Wang Yanen not only developed a set of printing control system, but also overcame the key mechanical technology of printing. This set of equipment unique room temperature piezoelectric ultramicro atomization spraying technology, breaking through the cellular fluid, protein liquid spraying speed, spraying volume is difficult to control the technical bottleneck of fine, at the international advanced level.

　　Animal tests have shown that the bionic bone can develop well after implanted in animal recipients, that is, through the metabolism of the recipients, the autologous cells will grow in the artificial bone and eventually grow into the autologous bone completely.

　　In the joint animal test between Northwestern Polytechnical University and the People's Liberation Army Air Force University of Military Medicine, no cases of rejection reaction have been found.

　　After testing, the 3D printed active bionic bone has reached a high degree of consistency with natural bone composition, structure, mechanics and other properties. Compared with other similar 3D printing technologies, it has obvious technical advantages.

　　Wang Yanen revealed, “Next, we will continue to explore the stabilized printing technology of sweat glands, hair follicles, sebaceous glands and other structures in the dermis layer, so as to be very close to the natural skin.” Currently, in their implantation trials of 3D printed rabbit skin, the bionic skin has a 25% shorter healing time than autologous skin. In the future, perhaps this technology could bring hope for healing to patients with bone defects, skin injuries and more.