| Electrospinning technology can be used as a co-spinning agent to electrospun polymers into fibers with micro-and nano-scale diameters and smooth,defect-free surfaces,and the fiber membranes have structural advantages such as high specific surface area and porosity.In tissue engineering,this structure can simulate the extracellular matrix well and provide a nice environment for cells to climb and proliferate.Controlling the polymer composition can provide antibacterial properties to the fibrous membrane,and replace the skin as a temporary barrier.These advantages make electrospinning technology promising for tissue engineering applications.Wound dressings as a branch of tissue engineering have been widely studied by researchers;researchers have reported a large number of electrospun dressings incorporating the above advantages of electrospinning technology.Most of these dressings use single or multiple spinning with uniaxial or coaxial needles,which causes the dressing to be in contact with the wound environment usually with one kind of electrospinning agent and slow release of the same soluble active material.To increase flexibility in dressing construction,it is necessary to develop a dressing that is capable of loading multiple active ingredients with different soluble fibers in contact with the wound at the same time.In the first part of this paper,a bi-component wound dressing with a parallel fiber structure was prepared by simultaneous electrospinning using a side-by-side electrospinning needle with water-soluble poly(ethylene oxide)and non-water-soluble poly(vinyl butyral)as electrospinning agents to loaded quaternized chitosan and zein,respectively.Microscopic observation of the bi-component membranes showed the complex of the two component fibers in the range of 0-3 μm in diameter to demonstrate the successful preparation of the bicomponent films.Wettability tests demonstrated that each composite membranes were able to absorb liquid relatively quickly within 20 s,and was able to absorb up to 400% of its own weight in phosphate buffer allowing it to absorb exudate while maintaining a moist wound environment.Biologically,the diameter of the inhibition circle for both Gram-negative and positive bacteria can reach 3 mm,indicating a certain antibacterial ability;the cellular activity of NIH/3T3 cells after 1d incubation is more than 85%,indicating that it is not cytotoxic and suitable for cell migration and proliferation.In the second part,the second electrospinning was carried out to address the poor mechanical properties of the original bi-component fiber membrane,and a layer of thermoplastic polyurethane was added to the original fiber membrane as a reinforcement layer to provide mechanical properties.The highest tensile strength can reach 34 MPa and elongation at break is 200%,which is sufficient to cover the mechanical strength of the skin in case of wound.Other performance tests showed that the addition of the TPU reinforcement layer had a limited impact on the material properties of the bi-layer membrane:microstructure with well-defined fibers and no surface defects;wettability with rapid absorption of liquids within 35 s,and the ability to absorb more than 300% of its own weight in buffer.Biologically the inhibition circle was reduced significantly;the NIH/3T3 cells had more than 120% cell activity after 1 d of culture,indicating that the addition of the toughened layer was beneficial to cell proliferation.It can be predicted that the prepared bilayer three-component side-by-side electrospun composite film with certain mechanical strength and excellent biocompatibility meets the basic requirements as a wound dressing and can be a potential choice for wound dressing;parallel spinning allows greater flexibility in the configuration process of spinning solution,providing an option for the development of electrostatically spun dressing that is different from the traditional spinning structure and providing a new research direction. |
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