Preparation And Performance Study Of New Composite Hydrogels Based On Chitosan

As a kind of natural cationic polymer material,chitosan is produced by partial deacetylation of chitin,which acheives excellent biological properties such as cytocompatibility,biodegradability,anti-inflammatory activity,and antioxidative capability,etc.It was widely utilized in tissue engineering,drug delivery,and electronic skin.Whereas,traditional hydrogels lack with mechanical properties,adhesion abilities and fatigue resistance.With the rapid development of smart materials,multifunctional hydrogels with high strength mechanical properties,self-healing,electrical conductivity sensitivity,and biocompatibility are becoming hotspots.This paper is dedicated to researching the preparation and properties of novel chitosan-based composite hydrogels.Based on these results,the applications of as-prepared samples in wound dressings and flexible sensors were also revealed.These works can be devided into the following two parts:1.Preparation of chitosan/dopamine/polyacrylamide(CS/PDA/PAM)hydrogel and its application in the wound dressing:The mechanical properties for the chitosan-based composite hydrogel were discussed with different component rates.In detail,its maximum tensile strength could reach 114 KPa and elongation at break up to 1152%.The introduction of dopamine in the gel resulted in a composite hydrogel with good self-healing and tissue adhesion properties.The introduction of chitosan not only enhanced the mechanical properties of the hydrogel,but also imparted excellent antibacterial properties to the hydrogel.In vitro antibacterial tests showed that the CS/PDA/PAM hydrogel had good antibacterial properties,and the inhibition rate of Staphylococcus aureus and Escherichia coli could reach over 98%.Experiments on the skin total injury model showed that the CS/PDA/PAM hydrogel could effectively promote wound healing.The prepared composite hydrogel has high stretchability,high tenacity,self-healing,tissue adhesion and cytocompatibility,which can promote skin tissue regeneration and wound healing and can be used as a good wound dressing.2.Flexible carboxymethyl chitosan/gellan gum/polyacrylamide(CMCS/GG/PAM)conductive double-network hydrogels and their applications in flexible sensors for human motion monitoring:The CMCS/GG/PAM double-network hydrogels obtained based on the double-network energy dissipation mechanism not only have good antibacterial properties,but also have excellent mechanical properties,light transmission,electrical conductivity and adhesion.CMCS not only imparts strong antimicrobial properties to the hydrogel,but also enhances the interaction between the GG and PAM networks.The physically cross-linked GG network synergistically enhances the mechanical properties of the hydrogel with the chemically cross-linked PAM network.The hydrogel can reach a fracture stress of 188.22 KPa and a fracture strain of 850.71%.The mechanical properties of the hydrogel can be controlled and adjusted by adjusting the ratio of the components of gellan gum and acrylamide.CMCS/GG/PAM DN hydrogels have good adhesion properties and can firmly adhere to solid surfaces such as aluminum,titanium,pigskin,stainless steel,etc.The hydrogen bonding between the hydrogel and the substrate makes its interfacial toughness reach 71.09-176.81 J/m2.CMCS/GG/PAM DN composite hydrogel has good adhesion properties.The CMCS/GG/PAM DN composite hydrogel has excellent biocompatibility and conductive strain sensitivity,enabling real-time monitoring of human motion status and facial micro-expressions,and therefore can be used as a safe antimicrobial flexible sensor for human health monitoring.