| Electrospun membranes loaded with anti-inflammatory drugs could act as physicochemical barriers to separate the postoperative adhesion-prone tissues.As drug carriers,electrospun materials not only help to prevent fibroblasts from infiltrating from the outer chamber,but also can regulate drug release behavior by regulating corresponding process parameters.However,the uncontrolled drug release pattern may lead to locally excessive concentrations and unrestricted dispersion,thereby interfering with tissue repair.Herein,an innovative double-layered scaffold endowed with unidirectional and sustained drug delivery capabilities was designed to precisely prevent peritendinous adhesion without hampering the healing outcome.Firstly,vortex-assisted electrospinning system was utilized to fabricate ibuprofen(IBU)-loaded with concentrationgradient and porous poly-l-lactic-acid(PLLA)fiber bundles membrane(PFB-IBU)as the outer antiadhesion layer.Then,the anisotropic collagen nanofibers were deposited onto the anti-adhesion layer to form the inner layer favoring tendon repair.First of all,by controlling that the electrospinning process parameters are the same,the receiving device is converted from a metal plate to a self-built vortex-assisted electrospinning system + collecting roller device,and the effects of the two electrospinning processes on the morphology,mechanical properties,orientation,hydrophilicity,pore size and other properties of the fiber membrane are compared.Then the IBU was loaded on the electrospun membrane,and the effects of different processes on the IBU loading and slow release behavior were compared.Finally,a layer of collagen fiber was deposited on the surface of the anti-adhesion layer to obtain a doublelayer anti-adhesion stent.In the study,several scaffolds were tested through a series of in vitro drug releases,in vitro cell tests,and in vivo biological experiment characterization,and the main research conclusions are as follows:(1)The fibers obtained by vortex-assisted electrospinning system are intertwined and twisted to form a fiber bundle membrane(PFB)with a certain twist under the effect of water eddy current.Compared with the fiber membrane(PF)obtained by conventional electrospinning,the mechanical properties of the fiber membrane(PF)are significantly enhanced,and it presents a threedimensional structure.The fibers are closely arranged,but there are large pores between the fiber bundles.But it has little effect on the surface microstructure and diameter of PLLA fiber.(2)The fiber bundle structure obtained by vortex-assisted electrospinning system can effectively prolong the release period of IBU,and the porous structure on the fiber surface can effectively solve the sudden release of IBU.More importantly,IBU presents a concentration gradient distribution in the thickness direction of the PFB membrane,which makes the total release rate of IBU from the high concentration side and the low concentration side vary greatly.(3)The collagen layer was deposited on the low concentration side of the PFB anti-adhesion layer loaded with IBU to obtain a double-layer anti-adhesion scaffold,which effectively prevented the inward diffusion of IBU,showing an obvious unidirectional release effect.At the same time,the collagen fibers showed dense accumulation and highly oriented arrangement.(4)Fibroblast proliferation at the high concentration side was successfully inhibited without affecting the oriented growth of fibroblasts at the collagen side.In vivo evaluation confirmed the peritendinous anti-adhesion effects of our double-layered scaffold in that both macrophage infiltration and deposition of pathological adhesion markers such as α-SMA and COL-III were inhibited,which may greatly accelerate the tendon healing process. |
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