Additive manufacturing of scaffolds with sub-micron filaments via melt electrospinning writing

TLDR

Melt electrospinning writing deposits polymer filaments layer‑by‑layer to build discrete 3‑D scaffolds for in‑vitro studies. The study aimed to determine the lower resolution limits of an electrohydrodynamic melt‑direct‑writing process. By optimizing flow rate, spinneret diameter, voltage, and collector distance for polycaprolactone, the authors achieved coherent scaffolds with ultrafine filaments (≈817 nm) arranged in box‑like structures of 100 µm periodicity and 80 µm height. The resulting ultrafine filaments exhibited oriented crystalline regions after 55 °C annealing, and the scaffolds, printed on NCO‑sP(EO‑stat‑PO)‑coated glass, remained attached during repeated liquid exchanges for at least ten days in vitro.

Abstract

The aim of this study was to explore the lower resolution limits of an electrohydrodynamic process combined with direct writing technology of polymer melts. Termed melt electrospinning writing, filaments are deposited layer-by-layer to produce discrete three-dimensional scaffolds for in vitro research. Through optimization of the parameters (flow rate, spinneret diameter, voltage, collector distance) for poly--caprolactone, we could direct-write coherent scaffolds with ultrafine filaments, the smallest being 817 ± 165 nm. These low diameter filaments were deposited to form box-structures with a periodicity of 100.6 ± 5.1 μm and a height of 80 μm (50 stacked filaments; 100 overlap at intersections). We also observed oriented crystalline regions within such ultrafine filaments after annealing at 55 °C. The scaffolds were printed upon NCO-sP(EO-stat-PO)-coated glass slide surfaces and withstood frequent liquid exchanges with negligible scaffold detachment for at least 10 days in vitro.