Preparation Of Electrospun Mats With Dimensional Stability, Controllable Degradation And DNA Release Behavior

Two strategies were proposed to prepare fibrous scaffolds with both stable dimensional morphology and controllable degradation behavior by un-axial and coaxial electrospinning—a facile and promising route in preparing scaffolds for tissue engineering. One is to blend a semi-crystalline polymer which displays slow degradation behavior with an amorphous polymer, the degradation rate of which could be finely tuned by changing its composition. Another is to use coaxial electrospinning technique to fabricate nanofibrous meshes composed of rigid polysaccharides. In addition, we demonstrated the capability of coaxial electrospinning for incorporation and sustained release of biomacromolecules or DNA into non-woven meshes.The effect of PLGA/PCL blending on the morphology, shrinkage and degradation behaviors of the electrospun composite fibers was investigated. The serious shrinking of the electrospun PLGA mats could be circumvented by adding 20% PCL in the fibers, resulting from the semi-crystalline nature of PCL. The degradation rate of the electrospun meshes could be modulated by PLGA/PCL composition, and the electrospun meshes containing more than 20% PCL displayed stable dimensional morphology. As a result, the fibrous scaffolds with stable dimensional morphology and tunable degradation behavior could be obtained by blending PLGA and PCL.Nanofibers composed of a rigid polysaccharide, such as chitosan, alginate and hyaluronic acid, were obtained by coaxial electrospinning. The polysaccharide mat prepared by the above method is dimensionally stable even in deionized water. Thus, natural biomaterial which can not be fabricated into fibrous scaffolds by regular uni-axial electrospinning could be prepared into stable electrospun mats as tissue engineering scaffold.The coaxial electrospinning was also adopted again to incorporate cationized gelatin and DNA (pEGFP) complex into PCL fibers. It was found that the complexes with small particle size could be prepared when the CG/DNA weight ratio was over 40:1 and sustained release of DNA/CG complexes from the electrospun fibers could be achieved.