Preparation And Application Of Silk Fibroin/Chitosan Composite Intelligent Hydrogel

Hydrogel is a hydrophilic three-dimensional network polymer material,which is insoluble in water,but has the ability of swelling and water retention.Intelligent hydrogel is a hydrogel that can respond to changes in external conditions,including pH value,temperature,ion strength,electric field intensity,magnetic field intensity,etc.The performance controllability of intelligent hydrogels and the stimulation responsiveness resulting from environmental changes make it have a great application prospect in drug release.As a natural polymer material,silk fibroin has good biocompatibility,biodegradability and excellent mechanical properties.Chitosan is an alkaline amino polysaccharide,which has wide sources,abundant reserves,good biocompatibility,biodegradability and natural antibacterial activity.The hydrogel made from chitosan will have potential application value in the field of biomedicine.In this paper,the composite hydrogel was prepared by chemical crosslinking using silk and chitosan as the base materials.The microstructure,mechanical properties,thermal stability and swelling properties of the composite hydrogel were studied with different mass ratio of silk fibroin and chitosan.And the intelligent response of composite hydrogel was verified by changing external stimuli.Using methylene blue as a model,we explored the sustained release behavior of silk fibroin / chitosan composite hydrogel at different pH values.First of all,N-(3-Dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride(EDC)/ N-Hydroxysuccinimide(NHS)as crosslinking agent to prepare the silk/chitosan composite hydrogel with different mass ratio.Then the effects of different quality on pore structure,compression strength,resilience and swelling degree of gel were studied.The results showed that silk fibroin and chitosan could form composite hydrogels under the action of EDC / NHS.With the increase of the mass of chitosan in the gel system,the gel aperture range was decreased from 10.64 + 1.27?m to 7.70 + 0.37?m,and the porosity rate increased from 71.50% + 8.45% to 85.26% + 4.61%,and the swelling degree of the gel increased,up to 300%.When the mass ratio of silk and chitosan was 8/2,the compression strength of the gel was the largest.Secondly,comparing the swelling degree of the composite hydrogels under different temperature,pH and ion strength.The results showed that the swelling degree of composite hydrogel had no regular change under different temperature conditions.Under acidic conditions,the swelling degree is larger,and the swelling degree is smaller under alkaline conditions.And with the increase of ionic strength,the swelling degree of gel decreases rapidly.Therefore,the composite hydrogel showed a certain pH and ionic strength responsiveness.In the end,methylene blue was used as the drug model to explore the sustained release of compound intelligent hydrogel in the human body temperature environment.The results showed that the loading rate of the gel was high,about 50%,and the release rate was higher in acidic conditions,with a maximum of 73.05%,and the release rate was prolonged and slow.