|
By electrospinning technology to prepare the continuous submicron fiber material (commonly known as nano fibers), because of its size and morphology unique biomimetic properties and good cell and tissue compatibility and biomimetic stent constructed in tissue engineering has a unique development prospects, today regenerative medicine, tissue engineering scaffold research has now become popular. However, electrospinning jet uncontrollable currently prepared nanofiber scaffolds were tested fiber direction any arrangement of the non-woven form, which used to build higher requirements on the mechanical properties, fiber orientation by the arrangement of composition anisotropic dense connective tissue (such as tendons, ligaments, etc.), is still a very challenging problem. The development of a variety of methods in the previous studies, hexyl micron ultrafine fibers collected directional satisfied including the use of high-speed rotary drum, etc., but various methods of preparing oriented satisfied one micron ultrafine fibers in the degree of orientation of the fibers can be collected to the length of the yarn bundle, yield, and mechanical properties there is a wide gap between the actual application requirements. Accordingly, the present subject to study the by electrospinning fundamental control jet stability, to be easily prepared by the serials, orientation, superfine, the possibility of the strength of the fibrous material, and thus be able to design and develop a new generation of practical value bionic fiber material, meet with structure-specific tendons, ligaments, and other organizations to build in the future, the use of demand. In this study three biodegradable polymer material chitosan (CTS), polycaprolactone the cool (PCL), polylactic acid (PLLA) as the object of study, and found that by adding a small amount of ultra high molecular weight polyethylene oxide in the spinning solution ethylene (Mw gt; 5,000,000 Da) can be significantly regulate these spinning liquid viscoelastic unstable bending swinging suppress electro-spinning jet, the single electrical spinning stability jets, which can be like traditional industrial dry , wet spinning as oriented fibers. We created this very simple electric drive spinning superfine directional fiber can be called stable jet electrospinning (stable jet electrospinning, SJE). Thus, we successfully prepared a diameter of 1 ~ 10μm microfiber monofilament length of the fiber bundles of about 30 cm and 30 cm × 20 cm high oriented polymer microfiber membrane. The preparation of these oriented fibers are based on an improved electro-spinning apparatus, comprising a controllable speed drum collector and fiber cross longitudinal ejection. SJE jet continuous, stable, non-real-time image confirmed unstable bending swing phenomenon captured by high-speed cameras. Further, use SJE method we can also be prepared in the orientation of the composite fibers of the core - shell structure, which ultrafine bionic oriented fibers functional offer great possibilities. Based on stable jet electrospinning electric drive mechanism and process of preparation continuous, directional, ultra-fine, high-strength tissue engineering scaffolds constructed using fiber material system two studies: (1) SJE spinning regulation; relationship between the state structure and mechanical properties of molecular aggregates (2) SJE prepared fiber. The results show that: the viscoelasticity of the polymer solution is to determine the the SJE law ability to form stable jet key factors. The electrically driven stable jet spinning process, the fiber diameter as the voltage and the drum speed increased thinning. SJE Preparation of ultrafine fibers having a high mechanical properties, such as the CTS, the PCL of PLLA fiber modulus reached 11 ± 6 GPa, 40 ± 10 MPa, and 2.13 ± 0.73 GPa; rupture strength at 762 ± 93 MPa, 120 ± 30 MPa, 205.62 ± 46.35MPa range. By X-ray diffraction analysis and polarizing infrared spectroscopy of molecular orientation and crystal orientation of the fibers, we found that the ultrafine fibers prepared by the stable jet electrospinning method with conventional electrospinning fibers prepared, compared with the higher molecular the degree of orientation, and degree of crystal orientation. The collection process, the drum speed increases further stretching of the fiber is conducive to the improvement of the molecules and degree of crystal orientation of the fibers.
|