| Scaffold materials play an important role in most tissue engineering fields. Almost all biodegradable natural macromolecules and synthesized polymers biomaterials have been used as the scaffolding materials. In recent years, researchers have developed many technologies to fabricate tissue engineering, including thermally induced phase separation, particle leaching, electrospinning and so on. Because of its consistency in producing fiber in submicron range, electrospinning has gained much attention. Electrospun three-dimentional fibrous scaffold can mimic the structure of natural extracellular matrix (ECM) and can favor cell adherence and proliferation. So far, eleetrospun fibrous scaffolds have been used for constructing of many tissues engineering especially bone tissueeng in the tissue engineering way.The size of rod-like nano-hydroxyapatite (nHA) which synthesized by hydrothermal route is20-30nm X50-70nm. Then the active powder will induce the ring-opening polymerization of ε-caprolactone to obtain nHA-PCL composites with different percentage of nHA. nHA-PCL-3which contain5%nHA was choosed as the sample to select the proper electrospinning conditions. To get appropriate solvent, the paper studied two systems mixed solvent of DCM with DMF and DCM with formic acid and the volume ratios were all1:1and2:1. The result of SEM show that membrane fibers exhibited much cross-bonding structures and fibers cannot be single present in DCM/DMF system. For DCM/formic acid system, the surface appearance of membrane fibers was much better comparing with DCM/DMF, especially the volume ratio was2:1, the cross-bonding structures decreased clearly. Therefore the best electrospinning solvent for nHA-PCL composites was DCM/formic acid with volume ratio2:1. In addition, many tests with single factor changing was done to choose proper electrospinning concentration, electrospinning voltage and tip-to-collector distance(TCD), and through SEM pictures show that the appropriate parameters were respectively20%wt,15kV and15cm.After selecting the proper electrospinning parameters, nHA-PCL composite electrospun membranes with different percentage of nHA were prepared, and the structure and properties of electrospun membranes were analysised fully. The results of SEM show that:the electrospun membranes fibers diameter decline with the content of nHA increasing; nHA-PCL with1%wt,3%wt and5%wt membranes fibers show good appearance; whereas because of the nHA nanoparticle agglomeration, the membranes fibers with7%nHA became coarse and inconsistent. From the results of FT-IR and DSC, nHA-PCL electrospun membranes have higher crystallinity than composites without electrospinning. Because of different crystallinity, the mechanical property of nHA-PCL electrospun membranes were different, nHA-PCL-3electrospun membranes show the best mechanical property, and the tensile strength and breaking elongation of it were respectively29.2±1.1MPa and55.6±1.5%. nHA-PCL composite membranes were immersed in1.5SBF to study the bone-forming ability of membranes. After immersion in1.5SBF for7days, the formation of different amount deposit on electrospun nHA-PCL fibers was observed by SEM. Through the result of FT-IR, the main component of deposit was calcium phosphate, and the precipitate amount increased with increasing nHA content. Furthermore, after mineralization, nHA-PCL composite membranes show good hydrophily by contact angle measurement.To compare the properties of composites electrospun membranes containing nHA and PCL which are made by different compound styles, the paper did researches on PCL, nHA/PCL and nHA-PCL. The results of FT-IR, DSC and SEM indicated that nHA-PCL in which nHA particle had good dispersibility obtained higher crystalline degree than nHA/PCL and PCL electrospun membranes. The results of tests also showed that nHA-PCL electrospun membranes possessed better mechanical properties, thermostability and bone-forming ability in comparation with PCL and nHA/PCL electrospun membranes. |
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