Three-dimensional scaffold of electrosprayed fibers with large pore size for tissue regeneration

Abstract

Regeneration of tissues using biodegradable porous scaffolds has been an intensely investigated area. Since electrospinning can produce scaffolds mimicking nanofibrous architecture found in the body, it recently has gained widespread attention. However, a major problem is the lack of pore size necessary for infiltration of cells into the layers below the surface, restricting cell colonization to the surfaces only. This study describes a novel twist to the traditional electrospinning technology. In particular, collector plates are designed which allows forming very thin layers with pore sizes suitable for cell infiltration. Thin samples can be handled without mechanically damaging the structure and can be transferred into cell culture. These thin layers were stacked by layer-by-layer assembly to develop thick structures. Thirty day cultures of fibroblasts show attachment and spreading of cells in every layer. This concept is useful in regenerating thick tissues with uniformly distributed cells and others in vitro cell culture.

Thickness-controllable electrospun fibers promote tubular structure formation by endothelial progenitor cells

“…Thus, the EPCs colonizing the 3D scaffold were intact and stable even after removing the aluminum foil. 24 Furthermore, colonized EPCs formed tubular structures in the absence of any biomaterials including Matrigel, which is known to support tubule formation in 2D cultures. 35 In contrast, no vascularization was observed on traditional 2D scaffolds composed of PCL electrospun fibers, suggesting that only the pore size of the electrospun fibers regulated neovascularization of EPCs colonizing the 3D scaffolds.…”

“…However, methods to control the thickness of highly porous electrospun scaffolds are limited because electrospun fibers with a large pore size 8,24 and controlled scaffold thickness cannot be simultaneously collected with traditional flat collectors. 28 In this study, we simultaneously engineered the thickness and the pore size of electrospun fibers by designing a novel collector configuration.…”

“…Thus, the 3D scaffold structure remained intact without the fibers collapsing during the 3D cell culture, even after the aluminum foil frames were removed from the scaffold. 24 As previously described, 24 the colonized EPCs on the 3D scaffold were fixed using 3.7% formaldehyde, dried through an ethanol gradient, embedded in paraffin, stained with hematoxylin and eosin (H&E), and examined using a MIRAX MIDI slide scanner (Carl Zeiss, Jena, Germany). Also, cell morphology was confirmed using SEM after EPCs on the 2D or 3D scaffolds were fixed using 3.7% formaldehyde and dried through an ethanol gradient.…”

“…To produce the highly porous 3D electrospun scaffold, a novel collector with a void (0.5 cm diameter and 0.95 cm depth) was designed on a hexagonal polystyrene weighing dish (0.44×0.95 cm; Eagle Inc., Hodgenville, KY, USA) wrapped with an aluminum foil (16 µm thick). 24 A traditional collector with the same geometry as the novel collector, but without the void space, was also wrapped in aluminum foil for producing the 2D scaffold. Scaffolds (3D and 2D) were fabricated at the rate of 0.2 mL/h at 10 kV.…”

Next Generation of Electrosprayed Fibers for Tissue Regeneration

“…109 Further, the aluminum rim could be used to handle the porous scaffold in subsequent steps, minimizing damage to the thin layers. Since very few layers can be deposited, pore size can be controlled based on the deposited volume of the polymer.…”