Preparation And Properties Of Hydroxybutyl Chitosan And Its Composite Materials

Hydroxybutyl chitosan is a biodegradable,biocompatible,and water soluble chitosan derivatives,which can form reversible thermo-sensitive hydrogels by intermolecular hydrogen bonding under a certain concentration and temperature.Avoiding the traditional hydrogel residual chemical crosslinking agents.Due to it has many hydrogen bonds in its molecular structure,we can increase its performance by introducing new material.While it retains the amino of the chitosan,so it can be further modified to get some better performance.This paper prepared hydroxybutyl chitosan and its composite materials,which have good water solubility,biocompatibility and have good prospects in periodontal repair and wound healing.The main research contents and results are as follows:?1?Using alkalized chitosan as raw materials,1,2-epoxybutane as etherifying agent,sodium dodecyl sulfate as phase transfer catalyst,reacting in the islpropanol.The product is hydroxybutyl chitosan which can form reversible thermo-sensitive hydrogels under a certain concentration and temperature.It can be proved that hydroxybutyl has grafted successfully to the molecular structure of chitosan through infrared spectrum and nuclear magnetic resonance analysis.Using the Rheometer to test the effect of the storage modulus and loss modulus of hydroxybutyl chitosan in different temperature,and analyzing the mechanism of forming hydrogel.Observing the internal morphology of hydrogels by scanning electron microscope.Its internal structure is 3D network and distributes uniformly.Using the MTT assay and flow cytometer to test the effect of cell proliferation and apoptosis of periodontal ligament fibroblasts?PDLCs?by different concentration of hydroxybutyl chitosan.The experimental results show that all concentration of hydroxybutyl chitosan in this experimental have no cytotoxicity to the PDLCs and have good cell proliferation rates.To a certain extent,the HBC has the effect of promoting the cell proliferation and slowing down the cell apoptosis.?2?Graphene oxide was synthesized by modified Hummers'method.And the structure was tested through infrared spectrum,Raman spectroscopy,transmission electron microscope?TEM?.Combining hydroxybutyl chitosan with grapheme oxide to prepare hydroxybutyl chitosan-grapheme oxide?HBC-GO?composite hydrogels.Testing the effect of physical and chemical properties of HBC-GO after introducing GO into hydrogel through infrared spectrum,Rheometer and scanning electron microscope.The results show that there is no obvious influence on the structure of HBC-GO after introducing GO.The HBC and GO were combined by intermolecular hydrogen bonding.With the addition of GO,the mechanical properties and stability of the composite hydrogels have made some enhancements.Using the MTT assay and flow cytometer to test the effect of cell proliferation and apoptosis of periodontal ligament fibroblasts?PDLCs?by different addition of GO into the composite hydrogels.The experimental results show that all samples of HBC-GO in this experimental have no cytotoxicity to the PDLCs and have good cell proliferation rates.Compared with HBC hydrogels,the HBC-GO hydrogels have better abilities to promote cell proliferation and slow down cell apoptosis.?3?Hydroxybutyl chitosan-collagen was synthesized with MTGase as biocatalyst.And the reaction conditions were optimized through one-factor-at-a-time experiment.The optimal conditions were found to be as follows:the reaction time was 3h,the reaction temperature was 30?,the mass ratio of collagen to Hydroxybutyl chitosan was 1.2.The moisture absorption and retention test showed that the moisture-retention ability of hydroxybutyl chitosan-collagen was improved with the DS increased.In vitro antioxidant test,with the concentration and the DS increased,the H₂O₂ scavenging activity of hydroxybutyl chitosan-collagen was increased,especially with high DS.With the increased concentration of hydroxybutyl chitosan-collagen,the DPPH scavenging activity enhanced obviously at first stage,and then slowly increased at later stage.At high concentration,the DPPH scavenging activity of hydroxybutyl chitosan-collagen increased with the increase of DS.The results of cell viability of fibroblast suggested that hydroxybutyl chitosan-collagen could efficiently promote the proliferation of fibroblast.With the increase of concentration,the cell viability increased at first,and then reduced.