Preparation And Properties Of Cellulose-Based Self-Healing Hydrogels With Boride Bond Crosslinking

It is well known that cellulose is widely distributed in natural resources and,its content in various plants is almost 50%.Cellulose is a kind of linear natural polysaccharide composed by a series of D-glucopyranose rings linked through 1,4 glycosidic bonds.Cellulose has been widely used in many fields due to its good renewability,biocompatibility,degradability and low cost.Especially in the field of tissue engineering,in recent years,more and more attention has been paid to cellulose-based hydrogels.The three-dimensional network of hydrogels can well simulate human tissue structures,and thus hydrogels have been widely used in the fields of drug release(antibacterial,anticancer drugs),reconstruction and repair of tissues in the past few years.In recent years,with the development of modern life science,higher performance of hydrogels are demanded.When hydrogels are used for tissue repair,we not only hoped that they can provide a certain mechanical support for the tissue defect,but also hope that they have other functions of natural growth and metabolism of the human body,and can better simulate the life characteristics of the organism.It is found that the characteristics of self-healing hydrogels are similar to the ability of organisms to repair autonomously.The self-healing hydrogels can respond to the stimulation of external environment(pH,temperature,etc.),and also have the functions of self-diagnosis,self-regulation.The self-healing hydrogels have become a hot spot in the research of smart materials.Because of the structures of the hydrogels containing dynamic crosslinking bonds can be reversibly adjusted according to the changes of environment,they have a good self-repairing ability.In this thesis,a cellulose-based hydrogel crosslinked by boronate bonds was prepared by a simple synthesis method.Briefly,D-glucosamine-modified carboxymethylcelluos-e and 3-aminophenylboronic acid-modified polyglutamic acid were first synthesized.When we prepared the hydrogels composed of the modified carboxymethylcellulose and polyglutamic acid,we also added the antibiotic neomycin sulfate containing two pairs of o-hydroxyl groups.Through the formation of the boronate bonds between the D-glucosamine,the two pairs of o-hydroxyl groups of theantibiotics and the phenylboronic acid,the self-healing function and drug loading of the hydrogel were achieved.We examined the mechanical properties,self-healing properties,biosafety and antibacterial properties of hydrogels,and confirmed that the hydrogels have good water swelling properties,self-healing properties,biocompatibility and antibacterial properties.The drug encapsulation efficiency is about 90%.The hydrogel is very promising in the applications of tissue repair.