| The unique properties of natural soft tissues,such as muscle and skin,are closely related to their complex hierarchical structures and compositions.Therefore,it is of great significance to develop tissue engineering materials with excellent properties according to the structures and components and repair processes of natural tissues.Electrospun materials have been widely studied as tissue engineering materials because of their adjustable compositions and structures in microscopic,mesoscopic and macroscopic dimensions,showing distinct physical and chemical properties and biological properties,which could meet the repair requirements of different tissues.However,it is not clear how the fine structure such as diameter and orientation of electrospun fibers applied in muscle regeneration affects the biological performance of myocytes for muscle regeneration.Furthermore,considering the significance of blood vessels during wound healing process,in order to promote angiogenesis of electrospun materials,bioactive silicate particles have been introduced into electrospun composites materials so as to promote wound healing to some extent,while the effective range of bioactive ions concentration is narrow,and precisely controlling the release behavior of bioactive ions has become a major challenge.What's more,not only insufficient angiogenesis but also large amounts of wound exudates should be dealt with chronic wound.Therefore,it is of great significance to construct multifunctional electrospun materials for chronic wound healing.Therefore,a series of work were carried out to adjust the composition and structure of electrospun materials in different dimensions in this dissertation.First of all,the fine structure of fiber diameter and orientation of electrospun fibers at the microscopic scale was regulated by changing electrospinning parameters,and the biological effects of the microstructure regulation on myoblasts was explored.Furthermore,the effect of mesoscopic structure on precise release behavior of bioactive ions and its biological effect were investigated by adjusting the pore size of electrospun membranes and the distribution of bioactive particles at mesoscopic scale.Finally,Janus membranes modified with macroscopic-scale arrayed porous structure were built,and the controllable bi-directional liquid transmission performance was explored.Based on the characteristics of Janus electrospun membranes,composite wound dressings combined with bioactive glasses and superabsorbent particles,was further designed,and the effects of macroscopic structure modification of electrospun membranes on multifunction of water absorption and bioactive ions controllable backflow and the application of the dressings in wound healing were studied in particular.The specific research contents and conclusions in this dissertation include the following three parts:(1)The influence of the fine structure of diameter and orientation of acellular matrix electrospun fibers on the proliferation and morphology of myoblasts at microscopic scale.First of all,compared with the two methods of fabricating porcine skeletal muscle acellular matrix,acellular matrix with the high protein content and low cell residue was selected as the raw material of electrospinning.With changing electrospun parameters,such as the proportion of acellular matrix and solution concentrations,a series of electrospun membranes were prepared.Results showed the contents of acellular matrix added to PCL electrospun solution had little effect on fibers diameter.Moreover,the diameter could be controlled from 124 nm to 717 nm by adjusting the concentration of the electrospinning solution.In addition,electrospun fibers with random and uni-directional structures were obtained by adjusting the rotating speed of substrate.By seeding C2C12 myoblasts on the surface of electrospun scaffolds,it was found that the aligned structure of electrospun fibers had a significant promoting effect on the cell viability of C2C12 cells.The fibers with diameter 471 nm had the most obvious promoting effect on proliferation of C2C12 cells,but no significant difference was observed between fibers with diverse diameters.In addition,morphological observation showed that C2C12 could form a uni-directional arranged cell bundles on aligned electrospun fibers.(2)The influence of the regulation of pore size and inorganic particles distribution on precise release behavior of bioactive ions and biological properties of electrospun films at mesoscopic scale.By adjusting the electrospinning parameters,the aperture of electrospun films were controlled,which varied from 0.68 ?m to 50.46 ?m.Electrospun composite films with various calcium silicate distribution,such as distributed on the surface of film,distributed in the "sandwich layer" of films,uniformly embedded in the film,and wrapped in the interior of fibers,were prepared by combining with electrospraying technology.It was found that the electrospun films with small pore size structure and the calcium silicate particles embedded or wrapped into films manifested ions sustained release,and the cell proliferation experiment verified that the composite electrospun scaffolds with sustained release behavior of bioactive silicon ions could further promote the proliferation of endothelial cells more effectively.(3)The influence of Janus electrospun membrane modified with macroscopicscale arrayed porous structure on multifunction of water absorption and controllable bioactive ions backflow and diabetic wound healing.In this study,a composite dressing consisting of hydrophobic electrospun layer,hydrophilic electrospun layer,bioglass layer and superabsorbent layer was constructed.The macroscopic Janus membrane was fabricated by hot-pressing hydrophobic and hydrophilic electrospun membranes,which realized the function of uni-directional liquid transportation.The Janus membrane compounded with superabsorbent particles for further endowed composite dressing superabsorbent performance,and the water absorption capacity could reach 8.17 times of its own weight.Furthermore,the concentration of bioactive ions released from bioglass could be controlled with the modification of macroscopic arrayed porous structures by changing pore sizes and pore densities on Janus membranes.The composite dressings with inter-pore distance of 0.35 mm and pore-size of 3 mm could allow the most rapid ions backflow and trace ions backflow observed in Janus membranes without macroscopic porous structure modification.The diabetic rat wound model verified that composite Janus electrospun dressings with macroscopic porous structure modification could effectively relieve wound edema,promote wound angiogenesis and accelerate wound healing.In summary,regulation of composition and structure of electrospun materials in microscopic,mesoscopic,and macroscopic dimension manifested the fine structure controlling,precise release behavior of bioactive ions and multifunction of water absorption and controllable ions release of electrospun materials,revealed good prospects in application in muscle and skin tissue engineering. |
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