Research On Biopolymer Carrier Material With Hierarchical Structures

Biopolymers have been widely used in food,packaging materials and biomedical materials for their appealing advantages such as wide sources,excellent biocompatibility,biodegradability,non-toxic,and good film-forming properties.In recent years,functional delivery materials(for example,microcapsules and microspheres)generated by biopolymers attract great research interest due to their attractive applications targeted delivery and controlled release.In this work,three biopolymers(chitosan,sodium carboxymethyl cellulose and sodium alginate)are employed to generate biopolymers-based layer-by-layer assembled microcapsules and core-shell microspheres,then their properties and applications were studied and evaluated.Initially,a gas-liquid microfluidic approach was employed to generate layer-by-layer assembled biopolymer microcapsules with separated layer cavity.This approach exhibits incorporated advantages of microfluidic approach and LbL assembly method,and it can straightforwardly build LbL-assembled capsules in mild aqueous environments at room temperature.Particularly,using this approach we can build polyelectrolyte multilayer capsules with respective cavity in each layer,together with no need for organic solvent,emulsifying agent,and sacrificial templates.Importantly,the resulting capsules have the capability to separately encapsulate diverse components(e.g.,drugs and nanoparticles)in different layers of the LbL-assembled capsules,and they also exhibit a special release behavior.Then,a one-step based fabrication technique was employed to generate chitosan/alginate core-shell microspheres.It is important to note that using this method we can straightforwardly build chitosan/alginate core-shell microspheres in mild aqueous environments at room temperature without using of organic solvent and emulsifier.Moreover,the shell thickness of these chitosan/alginate core-shell microspheres can be controlled by controlling the concentration of calcium chloride in calcium chloride/chitosan solution,and the core of these chitosan/alginate core-shell microspheres has pH-responsive property with acid-triggered dissolution.Therefore,the release behavior of the microspheres can be controlled by controllingthe concentration of calcium chloride in calcium chloride/chitosan solution and the pH of the environments.In this work,biopolymer carrier materials with hierarchical structures were studied,a gas-liquid microfluidic approach was employed to generate layer-by-layer assembled biopolymer microcapsules with separated layer cavity,and a one-step based fabrication technique was employed to generate chitosan/alginate core-shell spheres,then performance and applications of the microcapsules and core-shell spheres were studied and evaluated.This approach can straightforwardly build LbL-assembled capsules through a completely green and environmentally friendly route.in mild aqueous environments at room temperature(without using any organic solvents,emulsifying agent and even a harsh procedure).Importantly,the resulting carrier materials with hierarchical structures have the capability to separately encapsulate diverse components in different layers of the carrier materials,as well as they exhibit a special release behavior.Thus,this work may provide important theoretical and practical basis for construction and application of biopolymer carrier materials with hierarchical structures,and may also offer new methods for biomedical applications in targeted delivery,controlled release,fluorescent labeling and so on.