Table 2.

Criteria for designing electrospun fibers and TE scaffolds.

Function	Design criteria
Strong, uniform and bead-free fibers	High-molecular-weight polymers having high ionic conductivity, concentration, or viscosity; high operating voltage in electrospinning process [39]
Thin fibers, needle-like tip design	Electrospinning at high voltages and low flow rates [40]
Aligned electrospun fibers	High rotating target speed [40]; collector geometry
Structural stability to retain tissue shape	Maintaining mechanical properties throughout the 3D scaffold by strong electrospun nanofibers
Transport of nutrients and waste in and out of the electrospun scaffold	High porosity and interconnectivity between pores formed by maintaining preferred orientation of fibers [41]
Degradation integrity of electrospun scaffold to leave host tissue	Balancing degradation and formation of tissue without toxic by-products [42]
Elimination of inflammatory response or toxicity from the electrospun scaffold	Materials must be biocompatible, nontoxic and noncarcinogenic
High cell seeding density and cell migration leading to tissue growth throughout the scaffold	Large pore size, high porosity and high interconnectivity between pores using preferred unit cell geometry of the electrospun scaffolds [43]
Better cell attachment and proliferation	Optimized surface chemistry/topography and high surface-to-volume ratio
New cell or ECM growth in preferred direction	Proper fiber orientation within the scaffold [22]
Growth of 3D tissues and organs	Specific 3D shape of electrospun scaffolds using preferred unit cell geometry [43]