Controlling Mechanical\nProperties of Medical-Grade\nScaffolds through Electrospinning Parameter Selection

Electrospinning (ES)\nis a versatile process mode for\ncreating fibrous\nmaterials with various structures that have broad applications ranging\nfrom regenerative medicine to tissue engineering and surgical mesh\nimplants. The recent commercialization of this technology for implant\nuse has driven the use of resorbable electrospun products. Resorbable\nelectrospun meshes offer great promise as temporary implants that\ncan utilize the layer upon layer method of additive manufacturing\nto incorporate porosity as a function of process parameters into a\nscaffold structure. The interconnected porosity and feature size known\nto ES have previously been observed to hold great potential for simulating\nthe natural cellular environment of soft tissue. This microstructure,\nproper degradation kinetics, and mechanical properties combine to\nprovide the design basis for artificial tissue structures that could\naid in not only wound healing but also true tissue engineering and\nregenerative medicine. While current advancement in the field is understood\nto be limited by material properties, the importance of optimizing\nmechanical properties with currently available materials should not\nbe overlooked. This work investigated the process parameter effects\nand interactions that control the structure–property relationship\nfor a range of medical-grade aliphatic polyester materials with a\nrange of intrinsic properties. An ε-caprolactone homopolymer\n(PCL), l-lactide homopolymer (PLLA), and Lactoflex, a copolymer\nwith intermediate properties relative to the homopolymers, were characterized\nbefore, during, and after the additive manufacturing process. The\ninteracting effects of process parameters, distance to collector,\nand dispensing rate were shown to produce variable-density, nonwoven\nscaffold structures. The resorbable mesh scaffolds of PLLA, PCL, and\nLactoflex demonstrated a broad range of mechanical properties (approximately\n1–10 MPa ultimate tensile strength and 5–390 MPa tensile\nmodulus). Postprocessing of scaffolds demonstrated removal of solvents\nand preservation of micrometer-sized features. Resorbable polymers\nand electrospinning can produce scaffold materials with excellent\nfeatures and offer tremendous potential in the field of implantable\nresorbable devices.