Preparation And Application Of Functional Hydrogel Based On Polysaccharide And Polyzwitterion

Hydrogel is a typical kind of polymers with a three-dimensional network structure.The high water content and three-dimensional porous network structure provide an excellent biomimetic environment for cells,tissues and organs to grow,repair or regenerate.Chitosan(CS)is the only alkaline polysaccharide with good biocompatibility and biodegradability,which can form CS ion network by coordination and secondary interaction in the presence of multivalent electronegative molecules or anions.The zwitterionic polymer is uniformly distributed with equimolar amounts of anionic and cationic groups on the molecular chain.The combination of such oppositely charged moieties imparts superhydrophilicity to the polymer,which can be used to prevent non-specific protein adsorption and to minimize bacterial or mammalian cell adhesion.In this paper,we develop a novel hybrid ionic-covalent chitosan/polysulfobetaine double-network hydrogels.Chitosan is physically crosslinked by multivalent anions and behaves as the sacrificial network.And SBMA is chemically crosslinked by N,N’-methylene-bis-acrylamide(MBA).We expect the destruction of chitosan network will dissipate energy,bear stress,and recover network structure upon rearrangement to promote the mechanical property of the DN gels.As a result,the hybrid DN gels have excellent mechanical properties,fast self-recovery ability,and excellent fatigue resistance.More importantly,chitosan and PSBMA are both compatible,and besides nonfouling properties of SBMA,chitosan has bactericidal effect.Thus,CS/PSBMA DN gels are very biocompatible and show a special “repel and kill” property.We believe that this hybrid DN hydrogels may find great potential in applications,such as artificial connective tissues and implantable devices.Due to the permanent destruction of chemically crosslinked hydrogels,we hope to crosslink the hydrogels by reversible chemical bonds or physical interactions,so that they have good self-healing properties to prolong their service life and broaden their applications.Then,we prepared a double physically crosslinked CS/PSBMA hydrogel by a simple “one-pot” method.CS forms a first physical network by citric ionic cross-linking,and PSBMA is crosslinked through hydrophobic micelles to form a second physical network.The developed hydrogel has good stretchability(1100 %)and excellent self-healing property(tensile strength recovered to 91.1 % after standing at room temperature for 24 h)that it is capable of repeating multiple self-healing(7 times)at the same breakage.Moreover,it can be well adhered to many substrates and has high sensitivity,which is able to detect small changes in the throat when speaking.So we believe that the prepared hydrogel has great potential as strain sensor for application in human motion detection and health monitoring.