Construction And Application Of Bioinspired Medical Materials With Strong Adhesion

Biomedical adhesive materials are kind of biomaterials with adhesion properties and special biomedical functions.Biomedical adhesive materials play important role in tissue repair,wound closure,and wound haemostasis,and can also be used as biomedical device coatings,displaying widely application prospects in the biomedical field.However,there are still some challenges for the biomedical adhesive materials in their practical applications,e.g.the low adhesion for the medical devices(e.g.,safety goggles)with low surface energy and the tissues.In this dissertation,four kinds of high adhesive biomedical materials with different properties(e.g.,antifogging,antibacterial,and haemostasis)are developed by rationally designing the molecular structure,optimizing the chemical compositions,and adjusting the physical and chemical properties of the adhesive materials.The research contents and obtained results of this dissertation are as follows:(1)Bioinspired adhesive coatings based on polyethyleneimine and tannic acid are prepared via a one-step deposition process.By varying the contents of the tannic acid in the complexes,the polyethyleneimine-tannic acid complexes coating exhibits superhydrophilicity(water contact angle less than 10.0°),endowing the substrates with excellent antifogging and self-cleaning properties.Compared to the commercial antifogging safety goggles and commercial antifogging agents coated safety goggles,the polyethyleneimine-tannic acid complexes coated safety goggles display excellent durability without any surface fogs after being treated for 2 h with 65℃ vapor.Besides,the growth inhibition rate of the bioinspired adhesive coating against Escherichiak coli and Staphylococcus aureus is reached 94.51%and 99.97%,respectively,suggesting that the coating exhibits outstanding antibacterial activity.(2)A novel adhesive is synthesized via esterification reactions based on polyethylenimine ethoxylated and 3-(3,4-dihydroxyphenyl)propionic acid.After being cured in water,the surface content of C-OH for the adhesives is up to 38.85%,indicating that the water promotes the outer surface enrichment of the catechol groups.The adhesive exhibits strong adhesion on various substrates in different environments,e.g.,deionized water,diverse pH solutions,phosphate buffered solution,and seawater.And the adhesive shows strong adhesive strengths to the stain steel and wood substrates,which are up to 1064.1 kPa and 1542.7 kPa,respectively.Furthermore,the adhesive can be quickly cured and then prevent bleeding from the wounds of the femoral artery,tail,and liver of the rats.(3)A facile yet effective strategy is developed to fabricate haemostatic alginate-CaCl2 hydrogel coatings on the surface of the syringe needles.By rationally designing the composition of the alginate-CaCl2hydrogels,the hydrogel with the CaCl2content being 10%can be used for the haemostatic coating,which can realize in-situ solid-to-gel transitions and that mechanical strength and adhesion properties are 235.0 Pa and 2.4 kPa,respectively.The haemostatic hydrogel coating displays good biocompatibility and can be rapidly and gradually dissociated in 24 h without affecting the healing of the wound sites.The haemostatic needle achieves in-situ synchronous haemostasis during vessel and viscera puncture in the normal animal as well as in animal models with hemorrhagic diathesis.(4)The bioinspired haemostatic hydrogel with strong adhesion is prepared based on gelatin and tannic acid.The gelatin-tannic acid hydrogel with the tannic acid content of 10%displays excellent underwater adhesion property(30.7 kPa),and mechanical performance(95.2 kPa),as well as can also withstand the burst pressure of 990 mmHg.The underwater adhesive and mechanical strengths of the hydrogel coating used for arterial puncture should be higher than 4.9 kPa and 86.0 kPa,respectively,which are obtained through the microfluidic channel-based simulated vessels and computational fluid dynamics.By adjusting the volumes of the precursor solutions,the haemostasis needles(22 G,25 G,and 30 G)are successfully prepared.The gelatin-tannic acid hydrogel-coated needles can completely prevent blood loss after both vein and arterial puncture in different animal models.