| At present, although fibrin glue(FG) has been widely used as a surgical adhesive, its components, fibrinogen and thrombin, obtained from human blood are not completely free from the risk of virus infection due to acquired immune deficiency and hepatitis. Gamma-polyglutamic acid (γ-PGA) synthesized by microorganism is of good biocompatibility and biodegradability,so it can be used as a kind of ideal biomedical material. In the paper, the preparation and biological performance of γ-PGA -gelatin biological glue crosslinked with the aid of water-soluble carbodiimide(WSC) is studied as fo11owing: 1. The preparation of γ-PGA -gelatin biological glue The preparation and the tissue adhesion property of the γ-PGA -gelatin biological glue is studied. The biological glue is prepared from the gelatin whose aqueous solution doesn't spontaneously set to a gel at 25℃and the different-molecular-weight γ-PGA by the cross-linking reaction of WSC. When gelatin concentration is lower than the incipient gelation concentration, the gelation time by the WSC-cross-linked γ-PGA -gelatin biological glue lengthen with an increase of the concentration of γ-PGA and gelatin and WSC, and the gelation time by the WSC-cross-linked low-molecular-weight γ-PGA -gelatin biological glue is shorter than the gelation time by the WSC-cross-linked high-molecular-weight γ-PGA-gelatin biological glue .when the concentration of γ-PGA is 40 mg.mL-1,the concentration of gelatin is 10 mg.mL-1 and the concentration of WSC is 120 mg.mL-1, the gelation time by the WSC-cross-linked γ-PGA -gelatin biological glue is close to the gelation time by the fibrin glue. The adhesion property of γ-PGA -gelatin biological glue is superior to the adhesion property of fibrin glue. The biological glue is characterized by IR, XRD and DSC. 2. Effect of additives on γ-PGA -gelatin biological glue Urea is a promising additive in all investigated additives. When Urea's concentration is more than 75 mg.mL-1, it can prevent spontaneous physical gelation of gelatin well. The adding of Urea doesn't change the characteristics of WSC-induced crosslinking and tissue adhesion of the formed biological glue. When the concentration of γ-PGA is 40 mg.mL-1,the concentration of gelatin is 10 mg.mL-1and the concentration of WSC is 80 mg.mL-1, the gelation time by the WSC-cross-linked γ-PGA -gelatin biological glue is close to the gelation time by the FG. The adhesion property of γ-PGA -gelatin is still superior to the adhesion property of FG. 3.The biocompatibility of γ-PGA -gelatin biological glue The growth and proliferation of the cultured cells is not significantly inhibited by the biological glue A and the biological glue B, whose results are grade zero or grade one in cell toxicity test. The biological glue A and the biological glue B have no hemolytic reaction and their hemolysis rates are no more than 5%. They have no acute systematic toxicity, no skin irritation reaction, no pyrogenic reaction and no derma sensitization reaction too. All results indicate that the γ-PGA -gelatin biological glue has good biocompatibility. 4.The hemostatic property of γ-PGA -gelatin biological glue Ear artery wound and liver resection wound models of the rabbit are made. Compared with the natural hemostasis, the hemostatical time of the FG group and the γ-PGA -gelatin biological glue group is shorter in ear artery wound model and liver resection wound model. So the γ-PGA -gelatin biological glue provides effective hemostasis and can be used as a potential clinical glue.
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