In daily life, accident and surgery may bring the human body with trauma and tissue defects. Wound repair, tissue regeneration and even organ regeneration has been a problem to researchers in biological field.

In the eleventh session of the Beijing life science academic annual meeting, Dai Jianwu, Chinese Academy of Sciences Institute Genetic and developmental biology, made a presentation entitled "biomaterials, stem cells and tissue regeneration" Report which describes his many research work. It’s so excited about the development on repair of trauma.

Collagen membrane: guided tissue regeneration

It is often referred to "bracket" in regenerative medicine and tissue engineering. What is the role it played in wound repair? Dai Jianwu used a popular metaphor to explain: like building a house, first setting up the shelf before you can contribute to the above. For tissue engineering, the bracket provides an environment good for cell adhesion, proliferation, differentiation and tissue regeneration.

There are many kinds of biological materials using as "bracket", including natural biological materials and synthetic organic polymer materials etc. Dai Jianwu team focus on natural biological material: collagen.

There are two reasons to choose collagen: the first one is that its source is very broad, such as cattle, pigs and other animal skin, mostly on the tendon of the total protein collagen, bovine tendon, its 85% of the total protein is collagen; and the second one is that it is a structural protein and animal and human similarity are very high, they are the main components of the extracellular matrix.

In Daijian Wu's laboratory, 《Science and Technology Times》reporter saw two collagen membrane materials: one is collagen sponge, and its main purpose is to stop bleeding. Another collagen membrane can be used for stitching, it has certain mechanical strength.

On the application of a collagen sponge, Daijian Wu said that his research team has developed collagen particles for war wounds such as penetrating wound by bayonets, bullets. In this study, the researchers made the collagen particles and can be used directly deal with the depth of the wound. Collagen has a good role in blood clotting and can promote tissue regeneration.

Collagen membrane which used for sewing have wide can be used widely and degradation slowly in the body. Currently, in clinical applications, the patient's hernia treatment can be used in this material. As the patient abdominal muscle defect, you can use this collagen membrane which has a certain mechanical strength to fill. Since this collagen membrane without using any chemical crosslinkers, while degradation and reproduction are synchronization in vivo, it can be very effectively guided tissue regeneration. Animal experiments show that it can guide the abdominal muscle regeneration. Yan Tai Zhenghai Biotechnology Company has developed regenerative medicine products by three collagen membranes which were approved State Food and Drug Administration the production. They used for oral tissue injury repair, skin damage repair and dural defects respectively. They have been used for over thirty thousand tissue injury patients to prove its good tissue regeneration guide.

     Dai Jianwu introduce that these two materials has a guiding role to regenerate tissue. For faster repair tissue such as skin tissue, the use of stents can meet the body's regeneration rate request.

Binding growth factor functional materials: accelerated growth initiative

In fact, some of the human body and skin tissues is different. Its restoration is needed to accelerate the regeneration rate. Both the above-mentioned collagen film material has only a guiding role, but not has a biological activity induced. If we want to reach to accelerate tissue regeneration and wound healing, we need to take another factor into account - growth factors. Growth factors can greatly accelerate the rate of wound healing and play an important role in wound healing process.

Daijian Wu told reporter that the collagen material and growth factors can promote and improve the speed and quality of wound repair tissue together. Thus, functional materials combined by growth factors and collagen material show increasingly unique superiority in the field of wound repair. This binding of growth factor and functional material isn’t repair passively, but take the initiative to produce an effect on the physical or physiological processes.

Daijian Wu presented unique laboratory collagen matrix with growth factor binding functional biomaterials. This material has a big difference with the traditional functional material.

Traditionally, when researchers made functional material, they just simple mix the growth factors and biomaterials. When such material is transplanted into the body, due to the action of body fluids, they cause the free diffusion of growth factors. That will result in three disadvantages: First, to achieve the effect of the repair, we need to increase the amount of growth factor and the cost; Second, excessive use of growth factors may have side effects; third, due to the proliferation of growth factors may lead to uneven growth of the material surrounding tissue.

 Daijian Wu and his research team used growth factors and collagen to make collagen combination by genetic engineering technology. This combination constitutes a unique function of the system to achieve high levels of local enrichment. That reduces the amount of material and regenerate tissue uniformly.

Bone repair material developed by the team is this functional material. It is made of bone material containing collagen and BMP-2 which can bind to collagen protein. BMP-2 is now found in bone morphogenetic protein family members. It is the most obvious and intensively studied bone growth factor to induce bone formation.

The team of researchers using genetic engineering technology makes BMP-2 specifically combined with collagen. After this combination transplanted to the human body, it can remain on the biological material in a long time, guided bone tissue regeneration and repair the defect of bone, so as to obtain excellent results. It has advantage in the market at present. The technology has independent intellectual property right. At present, the new bone repair products is detecting in the State Food and drug administration. Next year we will complete the pre-clinical trials. This innovative work is the CAS knowledge innovation project and a good job combining production and research.

About the technology's future prospects, Dai Jianwu said, since bone defect caused by the fracture, trauma, and tumor resection is a common clinical problem, demand for bone repair is very huge. The realization of the industrialization of this technology will bring huge economic and social benefits.

Similar applications include the repair of spinal cord injury. It is the serious damage to the central nervous on the clinical common. In fact, there are great differences in nerve injury and skin damage. Once the injury nerve, nerve regeneration will be formed to resist environmental, so it is an important problem in modern medicine.

In order to solve this problem, researchers establish rat model to develop multi-function of nerve repair material. This multi-functional material includes three parts. Collagen materials provide support and guidance for nerve regeneration. CBD-BDNF combining with collagen provides neuroprotection protect; EGF receptor inhibitors can reduce the inhibition of nerve regeneration signal. Through the combined application of various strategies, they can create a suitable environment for nerve regeneration.

Dai Jianwu introduced, It has been confirmed that the materials can effectively promote nerve regeneration after spinal cord injury and recover nerve action potential conduction. At present, the study on the big animal is also in progress.

Autologous stem cells: the most secure method for the future

With the development of regenerative medicine, stem cell therapy has become the most popular direction of current research. The human body has a certain amount of tissue stem cells or progenitor cells. They have the potential of multi-directional differentiation and is the seed cell in tissue regeneration and wound healing.
At present, there are many applications of stem cell therapy. Now the popular cosmetic is one of them. Dai Jianwu thinks, the most secure and convenient clinical treatment should be using autologous stem cells for the repair of tissue in future.

How to make effective use of autologous tissue stem cells is still a problem to be solved in tissue regeneration and wound repair.

In response, Dai Jianwu said, to maximize the use of stem cells mentality should be able to attract and capture collagen materials from autologous stem cell to participate in tissue regeneration. In other word, the majority stem cell transplantation of tissue defect need carriers. Of course, sometimes stem cell transplantation does not need, such as the treatment of leukemia. Therefore, research on stem cell carrier is a research direction of Dai Jianwu laboratory.

In the study, collagen materials developed by researchers can capture tissue stem cells. In rat model, researchers use collagen materials to repair rat’s defect of myocardial tissue. It confirmed that these collagen materials can effectively capture and enrichment of autologous tissue stem cells, and can effectively promote the regeneration of myocardial tissues. At present, Dai Jianwu's team is doing a large number of animal experiments. Clinical application will be in the near future.

In addition to myocardial tissue regeneration, tissue repair of decubitus patient also can use such material.

It showed bright prospect for human wound repair by autologous stem cells repair, perhaps in the near future, reproductive organs are no longer human dream.