Preparation Of Ordered Porous Materials Based On Microfluidic Emulsion Template

1980s,tissue engineering have been proposed,through the efforts of scientists,the use of tissue engineering technology have successful formed a human ear cartilage covered with a nude mice’skin.Which means that tissue engineering owns a broad prospects in clinical application.Tissue engineering aims at developing new solutions for tissue repair and regeneration based on biological substitutes.Scaffold is the heart of tissue engineering,it plays an important role on the culture of cell adhesion,differentiation,proliferation.A scaffold ought to meet several generic requirements:porous structure,good biocompatibility,biomechanical properties.To achieve a well-defined scaffold,a number of fabrication technologies have been applied to process biodegradable and bioresorbable materials into 3D polymeric or composite scaffolds of high porosity and surface area.Techniques,such as porogen leaching,phase separation,gas foaming,emulsion freeze drying,electrospinning,3D printing,extrusion,selective laser sintering,solid free-form fabrication,and rapid prototyping,have been suggested as capable of producing 3D structures for tissue growth.But the numbers of techniques available for turning biomaterials into scaffolds displaying the features required for a tissue engineering application is somehow limitied.Microfluidics is a science and technology involving physics,chemistry,engineering and biology that deals with the precise control and manipulation of small quantities of fluids constrained in microchannels.It has achieved rapid development in the fields of micro-mixing,micro-separation,micro-reaction and micro-detection.In this study,a newly desighed microfluidic device based on flow focusing geometry was developed to fabricate scaffolds of ordered pores.The main contents are as follows:1.Construction of Microfluidic Chip:The corresponding microfluidic chip is designed.The fluid channel is divided into inner phase inlet end,outer phase inlet end and collector end.In order to better observe the shear of inner and outer phase droplets,a certain length of square tube is added in the shear.The effects of the size of the pipe on the droplet size,the monodispersity and the stability of the droplet size were discussed.Finally,stable emulsion droplets were obtained.2.Preparation of Emulsion Droplet Template:Try to use sodium alginate or PEG-DA or silk fibroin solution as the external solution,non-toxic edible oil or silicone oil as internal phase solution,the formation of emulsion droplets.The appropriate surfactants are explored so that the droplets do not rupture and the droplets do not fuse with one another to form well-ordered droplet templates.The effect of internal and external flow velocity on droplet size and droplet formation spacing can be investigated by adjusting the flow rate.3.Preparation of Ordered Porous Materials:The stability of the emulsion droplet template in the three systems was determined and the material was cured.PEG-DA has photosensitivity,through ultraviolet light irradiation,PEG-DA can be polymerized into a gel.Calcium ion is added into sodium alginate to form sodium alginate molecule by calcium ion replacement,which makes sodium alginate gel.The silk fibroin was freeze-dried to form a sponge-like structure.The emulsion droplet template in the scaffold material is washed off with alcohol and freeze-dried to obtain scaffold material with ordered pore structure.4.Biological Application of Ordered Porous Materials:As the core of tissue engineering,stent material plays an important role in the adhesion,differentiation and proliferation of cultured cells.HepG2 cells were inoculated into the PEG-DA porous scaffolds to explore its application in cell culture.