Improved fabrication of melt electrospun tissue engineering scaffolds using direct writing and advanced electric field control

Abstract

Direct writing melt electrospinning is an additive manufacturing technique capable of the layer-by-layer fabrication of highly ordered 3d tissue engineering scaffolds from micron-diameter fibers. The utility of these scaffolds, however, is limited by the maximum achievable height of controlled fiber deposition, beyond which the structure becomes increasingly disordered. A source of this disorder is charge build-up on the deposited polymer producing unwanted coulombic forces. In this study, the authors introduce a novel melt electrospinning platform with dual voltage power supplies to reduce undesirable charge effects and improve fiber deposition control. The authors produced and characterized several 90° cross-hatched fiber scaffolds using a range of needle/collector plate voltages. Fiber thickness was found to be sensitive only to overall potential and invariant to specific tip/collector voltage. The authors also produced ordered scaffolds up to 200 layers thick (fiber spacing 1 mm and diameter 40 μm) and characterized structure in terms of three distinct zones: ordered, semiordered, and disordered. Our in vitro analysis indicates successful cell attachment and distribution throughout the scaffolds, with little evidence of cell death after seven days. This study demonstrates the importance of electrostatic control for reducing destabilizing polymer charge effects and enabling the fabrication of morphologically suitable scaffolds for tissue engineering.

Rheological Characterization of Biomaterials Directs Additive Manufacturing of Strontium‐Substituted Bioactive Glass/Polycaprolactone Microfibers

“…Materials : Poly(ε‐caprolactone) Capa 6430 and Capa 6500 were supplied by Perstorp (Perstorp, Sweden). PCL Capa 6430 ( M w = 37 000 Da) is commonly used for MEW . PCL Capa 6500 ( M w = 50 000 Da) was selected for incorporation into a composite with SrBG with a composition of 46.13 SiO 2 , 2.60 P 2 O 5, 24.35 Na 2 O, 20.18 SrO, 6.73 CaO (mol%) processed into particles as previously described …”

The effects of processing parameters on the morphology of PLA/PEG melt electrospun fibers

“…As an eco‐friendly microfiber/nanofiber spinning method, melt electrospinning has recently attracted scientific attention and broadened the scope for direct 3D writing of biopolymers for a range of scaffold designs in tissue engineering …”

Improved cell infiltration of electrospun nanofiber mats for layered tissue constructs

“…Melt electrospinning writing, which directly lays down the electrified polymer melt onto a grounded surface, can yield the fiber mats with large well‐controlled pores for better cell infiltration . However, the large fiber diameter, normally between 5 and 30 μm, deviates from the typical ECM fiber dimension . To this end, establishment of a cost‐effective strategy to improve cell penetration yet maintain the structural integrity and dimensional superiority of nanofiber mats will be highly desired …”