abstract Heart failure remains a major cause of death worldwide. Cardiovascular diseases are the cause of almost one third of deaths worldwide. Among cardiovascular diseases, the biggest cause of death is heart attack. The main pillar of any heart surgery is the opening of the surgical site in order to access the patient's organ, resulting in wounding and bleeding in the desired position. The challenges in traditional wound closure methods such as suturing have led to the development of suture replacement materials such as adhesives. The aim of the current research is to make and characterize the adhesive injectable hydrogel and electric current conductor for cardiac muscle tissue regeneration. Also, the concentration of gelatin (70, 150 mg/ml), thiolated gelatin (70 mg/ml), tannic acid (7, 20, 70 mg/ml), sodium Peridate (11.3, 16.8 mg/ml) and iron chloride (1.7, 4.8 mg/ml) are investigated to achieve optimal properties. In this regard, gelatin-tannic acid hydrogels with different concentrations of tannic acid, sodium peridate and iron chloride were made and characterized. Then we changed the concentration and functional group of gelatin in the selected optimal sample and after that we examined different concentrations of bio ionic liquid (Bio-ILs) to select the optimal sample. To select the optimal sample in each step, different tests such as scanning electron microscopic tests were used to eva‎luate the morphology of hydrogels. In addition, X ray diffraction tests, Fourier transform infrared spectroscopy and nuclear magnetic resonance tests were used to eva‎luate the properties of synthesized precursors and adhesive hydrogel. Next, swelling ability and degradation rate of hydrogels were eva‎luated. The compressive and cyclic compressive mechanical properties of hydrogels were investigated. In addition, the ability of hydrogels to adhere to natural tissue, the ability and duration of blood clotting, and their rheological properties were also eva‎luated. At the end, the interaction of hydrogels with cardiomyoblast cells and antibacterial properties were eva‎luated. The results showed that gelatin/thiolated gelatin-tannic acid-Bio-ILs by creating covalent connections of Michael addition (between thiol and amine group with quinone of tannic acid), Schiff base reaction (between amine group and quinone of tannic acid), hydrogen bonds (between thiol and amine group with phenol structure) ,ionic bond (between positive amine and Fe charges with negative thiol and phenol charges) and metal complexes (between Fe ions with amine, thiol and phenol group) was formed. It can be said that the addition of thiolated gelatin and Bio-ILs led to significant control of its physical, mechanical and biological properties by creating the mentioned connections.The results showed that the presence of modified gelatin improved the reversibility properties of the hydrogel, higher adhesion strength to the tissue and increased blood coagulation ability.In this regard, the presence of thiolated gelatin in the hydrogel caused a significant reduction in blood clotting time from 5 minutes to 3 minutes. Also, adding 40 mg/ml of Bio-ILs increased the adhesion strength from 270 ± 5 kPa to 341 ± 20 kPa. And the performed tests confirmed that gelatin/thiolated-gelatin-tannic acid adhesion hydrogel had no toxic response against cardiomyoblast cells and significantly improved the growth and proliferation of cardiomyoblast cells. Also ,the results of the antibacterial test also showed that the sample containing 20 mg/ml of Bio-ILs causes a significant increase in the amount of inhibition zone against bacteria.

مهشيد خرازيهاي اصفهاني

محمد خدائي , مسعود عطاپور