Study On Electrospun Core/shell Structured Ultrafine Fibers For Wound Dressings

With high specific surface area and high porosity, scaffolds composed of electrospun fibers can provide a barrier to bacteria for wound when used as a wound dressing. Moreover, electrospun membranes feature a structural similarity to the natural extracellular matrix (ECMs). Therefore, they can mimick the nanoscale dimension of ECMs to promote cell adhesion and proliferation. Coaxial electrospinning, a new electrospun technique to fabricate continuous composite nanofibers with a core/shell structure can provide a more effective method for the inclusion of therapeutic drugs into the polymer nanofibers and offer controlled release for the drugs.In this study, fibrous membranes of chitosan (CS), poly(L-lactide-co-ε-caprolactone) (PLCL) and core/shell poly(vinyl pyrrolidone) (PVP)/PLCL (C-PVP/PLCL) were produced by electrospinning and coaxial electrospinning, respectively. The morphology and structure of ultrafine fibers was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The C-PVP/PLCL and CS electrospun membranes showed relatively larger absorption in phosphate buffer solution (PBS) (501.3% and 476.2%, respectively) than PLCL electrospun memebranes due to introduction of the PVP component and core/shell structure. The mechanical properties of electrospun membranes were evaluated by tensile test, and the results indicated that the C-PVP/PLCL membranes showed relative strong tensile properties. C-PVP/PLCL membranes gained in tensile strength and elongation in wet state.Fibrous membranes containing berberine chloride (BC), i.e., PLCL (BC), and C-PVP (BC)/PLCL were produced by electrospinning and coaxial electrospinning. The BC loading efficiency of the PLCL (BC) membrane was high and coaxial electrospinning could lower the BC loading efficiency. At the early stage of BC released, a smooth release was recognized from PLCL (BC) membrane and a burst release was obviously observed from C-PVP (BC)/PLCL membrane. After 3 d, the final release percentages for above two membranes were nearly 50% and 90%, respectively. The dimension stability of electrospun membranes can be improved by hot-pressing. The release behavior of BC in electrospun membranes reinforced if hot-pressed at a fitting temperature. Studies on cell adhesion, proliferation and morphology on the fibrous membranes showed that the CS and C-PVP/PLCL membranes could mimic the structure of ECMs and positively promote cell-cell and cell-matrix interactions because hydrophilicity and charge balance. Results of the in vivo wound healing study on rats back showed that CS and BC component obviously enhanced wound healing compared with the control.