Study On Porous Collagen/Poly(Hydroxyethyl Methacrylate) Hydrogels

The artificial cornea with “center-skirt” structure has been extensively studied,and the skirt material is a key for preparation of “central-skirt” artificial cornea.The structure of skirt materials is generally designed as a three-dimensional(3D)porous structure to promote the formation of new tissue.The structure and porosity of the corneal skirt affect the adhesion and growth of the corneal cells.Therefore,it is important to prepare artificial corneal skirt with suitable porosity and inter-connective porous structure for scaffolds application.In this paper,the solid paraffin was dispersed into different sizes of paraffin microspheres in hot water by mechanical stirring,and the paraffin microspheres with diameter of 200-300 mm were selected.The effect of temperature on paraffin particles solidification was studied,and the superior curing condition for the preparation of paraffin template was sintered for 20 minutes under 50?.In this work,collagen was extracted by the combination of acid and enzyme.The physical and chemical properties of collagen were analyzed by the Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis(SDS-PAGE),Fourier Transform Infrared Spectroscopy(FTIR),UV-visible Spectrum(UV-vis)and Thermogravimetric Analysis(TG).Poly(2-hydroxyethyl methacrylate)(PHEMA)hydrogel with inter-connective porous structure was prepared by paraffin template method.The effects of mass ratio of HEMA to total volume on the structure,water content,mechanical properties,porosity and thermal stability of porous PHEMA hydrogels were investigated.It was found that with the increase of mass ratio of HEMA,the structure of porous PHEMA hydrogel becomes tight,the porosity decreases while the tensile strength increases gradually.Besides,little effect was found of the mass ratio of HEMA monomer on the thermal stability and water content of the porous PHEMA hydrogel.Collagen/PHEMA porous hydrogel was prepared by an immersion method.The collagen amount in the pore of composite hydrogel could be adjusted by the concentration of collagen solution.In this work,we investigated the effects of concentration of collagen solution on the performance of collagen/PHEMA porous hydrogels.The results showed that with the increase of collagen solution concentration,the content of collagen fibers,water content,thermal stability and hydrophilicity of porous hydrogel increases.Collagen fibers were interspersed in the pores of collagen/PHEMA hydrogels,so the tensile strength of collagen/PHEMA porous hydrogels was improved.Collagen is good in cell compatibility.So with the increase of collagen amount,the biocompatibility of collagen/PHEMA porous hydrogels was improved.Furthermore scanning electron microscopy(SEM)revealed that the collagen/PHEMA porous hydrogels prepared in 1mg/mL collagen solution had suitable amount of collagen fibers on the PHEMA shell,where the collagen fibers attached to the holes to form a cobweb-like structure.The presence of collagen fibers is conducive to cell adhesion and growth,and the network structure of collagen fibers in the pore is conducive to cell migration.