| Wound healing is a dynamic and complex process,it can be promoted by wound dressings effectively.Amongst the various wound dressing materials,biomedical textile dressings is a new-type dressing which is guided by biomedicine,based on fiber material,and supported by textile processing,which has been great concerned worldwide.Electrospinning is a simple while effective method for producing sub-micron or nano fibers.Considering the advancements of nanofibrous mats(i.e.,high porosity,large surface area and ease of achieving controllable processing),it has been regarded as an ideal candidate for wound dressings.However,the several inherent limitations of single-component electrospinning nanofiber dressings in some performance limited it to be widely applied.In view of the above situation,this study focuses on the fabrication of two-component/dual-drug nanofibers wound dressings via the dual-spinneret electrospinning.Firstly,the electrospinning jet fluctuation model was studied in depth,extracting the key parameters which influence jet flow,and establishing relationship with properties of electrospun precursor solutions.Furthermore,the effect of properties of electrospun precursor solutions on jet flow and the finally formed fiber morphology were analyzed,which provided theoretical basis for realizing the controllable preparation of hybrid nanofibers dressings.Poly(vinylalcohol)(PVA)and Poly(caprolactone)(PCL)hybrid nanofibers dressings were prepared through dual-spinneret electrospinning.Meanwhile,the silver nanoparticles(AgNPs)obtained via the Green Reduction Method and the ascorbyl palmitate(AP)were loaded to the PVA and PCL,respectively.And moreover,the preparation,physical and chemical properties,as well as wound healing property of two-component/dual-drug nanofiber dressings are systematically studied.The obtained results were described as follows:(1)The effect of solution properties on fibers spinnability and fibers morphologies was studied,and the model of solution property and electrospinning jet influence rule was established.The viscosity,surface tension and jet diameter were considered as the characteristic parameters which influence jet flow.PCL electrospun precursor solutions with different molecular weights,different solvent ratios and different concentrations were prepared,and moreover,the test viscosity,surface tension,conductivity,and dielectric constant change of different solution system,and the product morphology of each spinning solution after electrospinning were also tested.It is found that a certain solution viscosity is essential for fiber formation by electrospinning.Or to be more specific,the polymer molecular chain should reach a certain entanglement to resist the stretching force of electric field force.Meanwhile,the Rayleigh-Plateau instability could be suppressed through increasing solution conductivity and dielectric constant,thus to reduce the jet diameter and produce homogeneous and continuous fibers.(2)The green reduction reagent tea polyphenols was used to produce AgNPs,introducing Ag+ and TP into PVA water solution.The chelating effect between the Ag+ ions and hydroxyl groups in PVA and high viscosity of the PVA solution restricts the Ag crystal growth rate and AgNPs aggregation to ensure the monodisperse and small size of AgNPs.Moreover,the growth process of AgNPs was further realized through changing solution viscosity and the proportion of reducing agent,realizing the effective control of the particle size distribution of AgNPs.The influence of the addition of Ag+ and TP on electrospun precursor solutions viscosity and conductivity was tested,revealing the essential reasons caused these changed,and analyzing the influences of the above change on electrospinning jet flow and finally formed fiber morphology,thus to control fiber morphology and properties.Meanwhile,different crosslinking conditions were explored,and it is found out that under the crosslinking condition of glutaraldehyde concentration being 25 %,temperature 30 ℃,and time 48 h,the fibrous mats after crosslinking possess the fine water stability.Fibers morphology and fibrous mats pores structure can be still guaranteed after immersing in water for 48 h.(3)In dual-spinneret electrospinning,PVA nanofiber embedded AgNPs was on one side,while the other side included PCL nanofiber with AP.After the tests such as FTIR,TG and XRD,it showed that the hybrid nanofiber mats had been formed after the interlacing between two kinds of fibers.The pores of fibrous mats centralize between 1 μm and 2 μm,which can guarantee the breathability of wound.After soaking for 48 h,hybrid fiber mate can reach 300 % water absorption,which ensures the absorption control on tissue fluid.In the aspect of mechanical property,the breaking elongation of PVA fiber mate declines rapidly after embedded AgNPs,and interlacing of PCL plays the role of flexibilizer,which makes breaking elongation reach 99 % and breaking strength reach 4.65 MPa.The loaded AgNPs and AP exhibited an excellent antibacterial action which can effectively inhibit growth of bacteria.The hybrid nanofibers dressings were applied into skin wound model in rats.At 18 days post-operation,the wound had been repaired almostly,and the blood vessel and sebaceous gland can be observed in the excision wound tissues.Both animal experiment results and H&E histological observation showed that this dressing can speed up the wound healing.Sum up all the above studies,it can be seen that applying dual-spinneret electrospinning into the production of hybrid nanofibers dressings can realize two-component and double drug-loading,even multicomponent and multiple drug-loading.Meanwhile,the fiber morphology can be controlled effectively,thus to further improve the comprehensive property of fiber dressing.Nanofibers dressing composited by PVA/AgNPs and PCL/AP produced in this study can effectively promote wound healing,which is expected to be used in clinic treatment as a kind of biomedical textile dressing. |
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