Preparation And Property Study Of Tough Hydrogels Based-on Multiform Crosslinks

As soft materials with a high water and high resemblance with biological soft tissues,polymer hydrogels are widely used in the biomedical area such as drug delivery,scaffolds for tissue engineering,and tissue repair.Similar to the extracellular matrix,the polymer hydrogel has a three-dimensional network structure.It is always a challenge to improve the toughness of a network limiting clinical applications of hydrogels.To solve this problem,this paper applied multi-crosslinks into constructing effective polymer energy dissipation mechanism and improving the mechanical properties of hydrogels.(1)We applied the fabrication method of composite hydrogels into double-network hydrogels,which combining the advantages of both kinds of hydrogels,to prepare four different Nanoparticles/Alginate/Am composite double-network hydrogels with high tensile stress and extremely tensile strain.During the fabrication process,we soaked the hydrogel polymer into cations solution to form ionic bonds between the polymer chains.Compared with the conventional prepared method which always leaded to gelatin bug,this new method will develop the success ratio of gelatin and improve the mechanical properties of hydrogels.Then a series of characterization have been constructed to discuss the reinforcement of four nanoparticles with different shape and size.In addition,the dynamic mechanical analysis and cell cytotoxicity test have been done to investigate the potential application in tissue repair area.(2)To solve the problem that mechanical property of hydrogels containing ionic crosslinks reduced dramatically when soaking in the electrolytic solution containing much of anions.This paper used a novel method containing polymerization,dry-annealing and cation solution soaking to prepare PVA/AM/MA hydrogel containing covalent,ionic and crystalline crosslinks.These three different crosslinks could cooperate to develop the energy dissipation mechanism and improve the mechanical properties of hydrogels.In addition,the chemical stability of this hydrogel when soaking in the electrolytic solution containing much of anions was significantly enforced.The experimental results have proved that this hydrogel possessed super tensile stress of 8 MPa and high tensile strain of 600%.After soaking in the phosphate buffer solution for 12 hours,the tensile stress of this hydrogel was still 91% of original stress,which indicated outstanding stability.Finally,the cell cytotoxicity test has been conducted for the potential application in tissue engineering.The innovations in this paper:(1)Applying the fabrication method of composite hydrogels into double-network hydrogels containing covalent and ionic crosslinks,which combining the advantages of both kinds of hydrogels,to prepare four different Nanoparticles/Alginate/Am composite double-network hydrogels with high tensile stress and extremely tensile strain.(2)Using a novel method containing polymerization,dry-annealing and cation solution soaking to prepare PVA/AM/MA hydrogel containing covalent,ionic and crystalline crosslinks.These three different crosslinks could cooperate to improve the mechanical properties and chemical stability of hydrogels.