![]() During this process the solvent evaporates, and nanofibres are obtained 24, 25, 26, 27. In this method, a high voltage is applied to a polymer solution, which is then injected through a needle towards a grounded collector. However, the methods mentioned above are restricted in terms of the shape and size of the gels produced, and more practical and facilitative methods are desired.Įlectrospinning is a facile method for obtaining anisotropic nanofibre bundles. The repeated lyophilisation of a collagen solution in a columnar tube and the resulting anisotropic shrinkage of the obtained gel yields an anisotropic collagen hydrogel 23. For example, an anisotropic collagen hydrogel can be produced using low interstitial flow 20, by applying a shear stress with aspiration and injection through a needle 21, and by using shearing rotary between discs 22. Several methods for obtaining anisotropic collagen hydrogels have been reported. Thus, a collagen hydrogel with an anisotropic fibrous structure that mimics the microenvironment of ECM would be highly desirable for use as a cell scaffold, as it would allow for the control of the cellular microenvironment for constructing three-dimensional tissues and organs from cells 9, 15, 16, 17, 18, 19. In recent years, it has been determined that the geometry and shape of cells and their surrounding environment affect cell behaviour and function 10, 11, 12, 13, 14. However, this collagen hydrogel has an isotropic and homogeneous structure, which is different from the anisotropic three-dimensional structure of native living tissues 1, 2, 9. Collagen extracted from living tissues is used widely in the form of a hydrogel as a cell scaffold in regenerative medicine to ensure high biocompatibility and bioactivity 7, 8. This structure provides an ECM with high strength as well as anisotropic mechanical properties 4, 5, 6. It consists of hierarchically ordered fibrils, which are composed of rigid triple helices of three molecular chains 1, 2, 3. Hence, this method is suitable for fabricating fibrous anisotropic collagen hydrogels without chemical and thermal cross-linking, and can facilitate the development of safe medical materials with anisotropy similar to that of native ECM.Ĭollagen, a primary component of the extracellular matrix (ECM), exists ubiquitously in tissues such as skin, blood vessels, and tendons. Human umbilical vein endothelial cells cultured on the collagen hydrogel fibres were oriented along the fibre direction. Circular dichroism measurements confirmed that the fibres exhibited the triple helical structure characteristic of collagen. Immunostaining and Fourier transform infrared spectroscopy revealed that the obtained fibres were composed of collagen, and surface PVP was removed completely. Subsequently, the core collagen was gelled, and the shell PVP was washed away using a basic ethanol solution to yield anisotropic collagen hydrogel nanofibres. Herein, electrospinning using a core-shell nozzle was employed to spin an aqueous acidic solution of collagen and encapsulate it within a shell of polyvinylpyrrolidone (PVP). Electrospinning of collagen dissolved in organic solvents is widely used for fabricating anisotropic collagen nanofibres however, such fibres are water-soluble and require cross-linking before use as scaffolds for cell culture. In contrast, native ECM has an anisotropic structure. ![]() Collagen hydrogel is a popular extracellular matrix (ECM) material in regenerative medicine and has an isotropic structure.
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