Recent developments on preparation of aligned electrospun fibers: Prospects for tissue engineering and tissue replacement

Electrospinning as a straightforward method has been used for manufacturing nanofibers for many years but in a conventional electrospinning method, the obtained fiber meshes deposit randomly on the collector. However, the preparation of aligned fibers through the electrospinning method has attracted attention in recent years in different fields, including tissue engineering and tissue replacement. The anisotropic alignment of fibers in these structures resembles the natural structure of the extracellular matrix and provides topographical cellular cues to guide cellular growth for structurally anisotropic tissues, including nerves, blood vessels, esophagus, urethra, and essentially any tubular tissue. This review will focus on recent developments in electrospinning techniques and setups for the preparation of aligned nanofibers used as the scaffold for tissue engineering, including rotating collectors, gap electrospinning, stable jet electrospinning, hot-stretching, magnetic field-assisted electrospinning, centrifugal electrospinning, and near-field electrospinning. Then, different strategies for constructing complex nanostructures such as yarns and 3D patterned constructs from these aligned nanofibers to use as a tissue scaffold will be discussed. Furthermore, the large-scale preparation methods for manufacturing aligned electrospun fibers and different modification strategies of fibers including surface modification and composite preparation will be covered. Finally, some biomedical applications of aligned electrospun fibers will be mentioned.