Table 1.

Properties of TE scaffolds desired for different tissues and effects of electrospun materials on TE scaffolds.

Tissue	Biological description	Key engineering properties	Effect of electrospun materials on TE scaffolds	Use of scaffolds
Epithelial tissue e.g. skin	Joined together with same tissue; soft and elastic	Very low elastic moduli (0.1–0.2 MPa), optimum pore size (20–125 μm) [22]	Electrospun collagen nanofibers can improve the structural integrity and mechanical strength of skin tissues. The scaffolds made of electrospun nanofibers provide a high surface area-to-volume ratio, which promotes the cell–matrix interaction at the nanoscale [23]
Connective tissue e.g. bone, tendon, ligament, cartilage and fat	Joins different tissues; strong and tough	High tensile, compressive, and torsional strengths, high elastic moduli, optimum pore size for bone (100– 250 μm) [24], ideal porosity (>90%) [25]	Electrospun nanofibers with high surface porosity improve cell ingrowth and the mechanical properties of the scaffold [26,27]
Fluid tissue e.g. blood, fibrinogen (natural polymer present in blood plasma), thrombin	Transports food, nutrients and waste products; viscous	Specified viscosity, surface tension, mass transport property and pH	The high surface-to-volume ratio of the electrospun synthetic fibrinogen nanofibers can improve the blood clotting process in wound healing after reacting with thrombin by forming a network structure of a fibrous compound called fibrin [28]
Nerve tissue	Sensitive to various stimuli	Smart properties; high ionic, electrical and thermal conductivities, electrochemical and chemoelectrical transduction properties [29]	High aspect ratio of electrospun nanofibers enhances the conductivity of sensors via electron transport, which is extremely effective for nerve tissue scaffolds [29]
Muscle tissues:
Voluntary muscle tissue e.g. arm, leg and skeletal muscles	Made of striated muscle fibers supported by connective tissues and stimulated by nerves	Medium elastic modulus and high fatigue endurance under cyclic load	Electrospun nanofibers of polyester urethane and poly(l-lactide-co-ε-caprolactone) have satisfactory mechanical properties and encouraging cellular response in terms of adhesion and differentiation; they can be used in scaffolds for skeletal [30] or smooth [31] muscles
Involuntary muscle tissue e.g. intestines, heart or cardiac muscles	Smooth and not human-controlled; soft	Low elastic modulus and high fatigue endurance limit under cyclic load	Small intestinal submucosa (SIS) composed of type-I and type-III collagens and various cytokines leads to superior initial cell attachment and proliferation compared with synthetic polymeric scaffolds in presence of growth factors. Electrospun SIS/poly(ε-caprolactone) hybrids have a stable micro/nanofibrous structure, which provide improved hydrophilicity, mechanical properties and cellular behavior to the scaffolds [32]