Fabrication And Characterization Of The Tissue Engineering Scaffolds With High Open Porosity By Supercritical Carbon Dioxide

In this research, two new method were firstly put forward to fabricate PLA/β -TCP and PLA/ β -TCP/Collagen scaffolds with high open porosity by supercritical carbon dioxide (SC-CO₂). The two schemes are: (1) SC-CO2 repeatedly cycling introduction (RCI) and (2) SC-CO₂ fiber bonding with collagen fiber network on the basis of RCI. Both of the schemes are expected to ulteriorly solve the problem that the scaffold has too low open porosity by the SC-CO₂ traditional introduction one time (TIOT). The main research was focused on the influence of the different component proportion on the total porosity, open porosity, shape of the pore, and mechanical capacity of the scaffolds. And the feasibility of compounding active protein (e.g. Growth factors) was also researched by the model protein lysozyme compounded into the scaffolds by the two methods. The innovation point of this article is firstly adopting the two methods of SC-CO₂ RCI and SC-CO₂ fibre bonding with collagen fiber network to prepare higer open porosity scaffolds. Scanning eletronic microscopy (SEM) observation, scanning probe microscopy (SPM) observation, helium pycnometry test, mechanical capacity test, differential scanning calorimetry (DSC) test, epoxy resin embedding & staining collagen on the section, controlled release test, and biocompatibility test were done to characterize the scaffolds. The results showed:(1) The scaffolds made by RCI were found to have about 10% higher open porosity than that by TIOT method. The diameter of the pores are about 200-500 μm and there are several types of shapes of micro interspace in the pores. β-TCP can be evenly compounded into the PLA materials. T_g of pure PLA scaffolds by RCI and TIOT methods will be improved. The biggest compressure modulua and compressure strength of the PLA/ β -TCP are 71.8MPa and 7.1MPa.(2) The open porosity of the PLA/β-TCP/Collagen scaffolds fabricated by SC-CO₂ fibre bonding can achieve 82.81% which is 25% higher than the PLA/β-TCP scaffolds; The diameter of the pores is also 200-500 μm and there are many tunnels among the pores. Collagen fiber can maintain the network shap after SC-CO₂ processing and can be evenly compounded into the scaffolds. The...