Preparation Of Biocompatible Scaffolds With Hierarchical Interconnected Pore Structure By Combining Pickering Emulsion Templates With Three-Dimensional Printing

With the rapid development of medical technology,traditional biomedical materials can no longer fully meet the higher requirements aroused nowadays.Therefore,the research of biomedical materials which are capable to meet various clinical requirements has turn to be one of the focuses of scientists.By simulating the structure of natural extracellular matrix,we designed and fabricated biocompatible porous scaffolds with excellent biocompatibility,outstanding cell proliferation and differentiation,along with remarkable drug loading and release properties.By combining traditional and newly developed preparation methods,we provided new possibilities for the structural design of bio-porous scaffolds.The main research contents and results are listed as below:1.Hydrophobically modified SiO₂?h-SiO₂?nanoparticles were used as particulate emulsifier,while the CH₂Cl₂ solution of polycaprolactone?PCL?and poly?lactic acid??PLLA?were used as oil phase to prepare oil in water Pickering emulsion.Subsequently,the as-prepared emulsion was printed into h-SiO₂/PCL-PLLA scaffold with orthogonal palisade structure by 3D printing.The obtained h-SiO₂/PCL-PLLA scaffold possess with tens of microns sized small pores,hundreds of microns sized mesoporous and millimeter sized macropores.By adjusting the preparation parameters,it is found that the scaffold possesses the best comprehensive properties when the concentration of polymer is 6 w/v%,the content of stabilized particles is 2.5 w/v%and the volume of internal phase is 75%.Enrofloxacin?ENR?was used as a simulated drug to characterize drug release properties.In vitro drug release results show that 98%of ENR was released in 10 hours.The release process could be described by Hixson-Crowell model.In addition,after 7 days of cell proliferation on the scaffold,a fusion layer is formed on the surface of the scaffold,which shows that the scaffold has excellent biocompatibility.2.Utilizing h-SiO₂ nanoparticles as particulate emulsifier,suspension of CaCO3nanoparticles in CH₂Cl₂ solution of PCL as oil phase,adding gluconic lactone?GDL?in aqueous solution of alginate?ALG?as water phase,porous composite scaffolds with multiple drug loading functions were prepared by combining Pickering high internal phase emulsion template with 3D printing.Not only can oil-soluble anti-inflammatory drugs be loaded in the oil phase,but also water-soluble drugs can be carried in the water phase,thus the drug delivery system is further improved.Results show that the content of CaCO₃ nanoparticles have a great influence on the performance of the scaffolds.When the content is 0.1 w/v%,the scaffold exhibits the best comprehensive performance:emulsion with good stability and printable performance,scaffold possess highly interconnected pore structure as well as good mechanical properties and excellent performance in drug loading and release characterization.They exhibit rapid and complete release behavior for oil-soluble drugs,while for water-soluble drugs,they exhibit slow and sustained controlled release behavior,which greatly broadened the application of composite scaffolds in the field of bio-engineering.