| Guided Tissue Regeneration (GTR) is a procedure that enables injured tissue to restore using biomaterial membranes as a mechanical barrier that separates fast-growing soft tissue from the regeneration site, and create a space around the defects to permit tissue regeneration. GTR techniques have been successfully applied in the treatment of hard tissue such as periodontal and bone lesions for decades.Although the mechanical properties of these membranes for GTR were paid much attention, it is known the bioactive property is more important. If the biomaterials which integrate both the GTR membranes mainly barrier mechanism and bioactivity for example stimulating cells adhesion and growth, will be more powerful for GTR in tissue repair. Layered materials may be a rational choice that can provide different functions for the different layer chemical ingredients.In this study, we designed and prepared a new type of collagen/collagen-hyluronate double-layered membrane with one dense layer composed of collagen fibers, and one loosen layer of collagen and hyluronate composite, the physico-chemical properties were characterized. The biocompatibility was evaluated according to GB/T 16886 (Idt, ISO 10993) series standard. Then animal experiments were performed to investigate GTR effects of the double-layered membrane. And if the tendons trauma can be treated by GTR technique has also been investigated. The guided tissue regeneration function of the biomaterial has been investigated in a case of palate tissue defect after authorized for clinical test. As a type of dimension matrix, the membrane may be used as a scaffold in tissue engineering, so a primary study were performed by cultured the rabbit's smooth muscle cells (SMCs) and endothelial cell (ECs).The SEM results indicated the double-layered collagen/hyaluronate-collagen membrane was constructed with one face showed big pore size while the opposite face pore size smaller. The relative hyaluronate content was higher then control collagen matrices indicated that hyaluronate was cross-linked with collagen effectively. The physico-chemical characters of the matrix were satisfied for implant as a medical device.The biological risks had been evaluated according to the GB/T 16886 serial standard methods. It could be concluded that the membrane cytotoxity satisfied for the requirements of the standard. The acute system toxicity showed no obvious response and the all animals' weight have got increased. The hemolysis rate of the membrane was (0.49±0.01) %. There were no sensitization and irritations in all animals. To investigate the effects of the genetic toxicology, it was used to do the Ames test, micronucleus assay in bone marrow polychromatic erythrocytes and in vivo chromosome aberration test. The effects were evaluated by the ratio of polychromatic erythrocytes (PCEs) and normochromatic erythrocytes (NRBCs), the rate of micronucleus, chromosome aberration and the type of chromosome aberration to determine the mutagenesis. The results showed that the membrane has no chemical mutagen. The double layered membrane showed biocompatible.The results of the animal experiment were consistent with previous reports and confirmed histologically that the intrinsic mechanism were more desirable for the tendon healing. For this reason the tendon injury repairs through GTR technique maybe feasible. Clearly, during the repairing process the membrane had shown preferable cell occlusion function for GTR techniques. The clinical test in the case of palate tissue defect repair result showed the membrane was bio-safety and could guide the palate tissue regeneration.The membrane could promote the SMCs and ECs adhesion and proliferation when cells cultured on it. This results indicated the membrane maybe used as a tissue engineering scaffold.The double layered collagen/collagen-hyaluronate membrane could be a promising medical device, further studies are needed.
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