Research and Application of Medical Adhesives (2)

Normal> 1 Absorbs water from living tissue, rapidly solidifies, and strengthens adhesion with tissue;

After normal > 2 curing, the bonding site has a certain flexibility;

Normal > 3 relieves stress concentration at soft tissue anastomosis;

Normal > 4 adhesive storage stability;

Normal > 1      Has good biocompatibility and biodegradability.

Normal > For alpha - cyanoacrylates, the monomers contain strong electron-withdrawing groups - CN and -COOR , the combination of two groups makes it prone to anionic polymerization, and the presence of active double bonds to free radicals It is quite sensitive, so ionic inhibitors and radical polymerization inhibitors must be added both in the preparation process and in storage. At present, the most commonly used ionic inhibitor is sulfur dioxide, and the radical inhibitor is hydroquinone. In addition, when a condensate is obtained during the synthesis, residual water can be removed by washing with an acid to greatly improve the stability. In terms of modification, α - cyanoacrylates having different properties can be obtained by changing the structure of the ester group , or copolymerization methods can be used to introduce suitable copolymerization units to improve the properties thereof. On the other hand, the development of new varieties of chemical adhesives is also an effort. Research in these areas has made some progress, but no official products have yet been listed.

4   Bio-adhesive

normal> refers to the preparation of bioadhesive extracted from human or animal blood viscous products, and has been used in clinical varieties listed only fibrin sealant, also known as fibrin glue, autologous sources allogeneic into two kinds of sources.

4.1   Fibrin Adhesive ( FS )

The history of fibrin adhesives as medical adhesives dates back to the beginning of the last century. 1909 Bergel reported having hemostatic fibrin powder, followed by liver and brain that is applied to the hemostasis. Young 1940 attempts to use an adhesive severed peripheral nerve coagulation response, Tidrick and then use it to Cronkile like fixing skin grafts. However , it was not officially used by Matras as an adhesive until 1972 . Matras first used cryoprecipitation to extract high concentrations of human fibrinogen, plus a high concentration of bovine thrombin and Factor XIII to make the adhesive for peripheral nerve anastomosis and to achieve success. As a result, a large number of experiments and clinical applications have been conducted, which has enabled the rapid spread of medical preparations that function to stop hemostasis and adhere to the wound. This has been widely used in the surgical field in Europe, the United States, Japan, and other countries. There are also many products available in China.

Normal > In recent decades, its efficacy, safety, etc. have been confirmed through its research on its principle of action, histopathology, pharmacodynamics, and clinical application. There are currently no ideal hemostatic drugs or materials for wound bleeding from trauma and surgical incisions, especially the wounds of parenchymal organ wounds. In the past, gelatin sponge was used to locally stop hemostasis, but the effect was not good. Less than the purpose of hemostasis. Fibrin adhesives can be used for almost all oozing wounds, with adhesive tissue, covering wounds, filling defects, and voids.

4 . 1 . 1   Basic composition and function principle

Normal > Fibrin adhesive consists of three major components: 1 fibrinogen ( fibrinogen ), the main component, present in plasma. It is a biological macromolecule with a molecular weight of 340KD and consists of 3 pairs of peptide chains A α 2