Expanded 3D Nanofiber Scaffolds: Cell Penetration, Neovascularization, and Host Response

Abstract

Herein, we report a robust method to fabricate expanded nanofiber scaffolds with controlled size and thickness using a customized mold during the modified gas-foaming process. The expansion of nanofiber membranes was also simulated using a computational fluid model. Expanded nanofiber scaffolds implanted subcutaneously in rats showed cellular infiltration, whereas non-expanded scaffolds only had surface cellular attachment. Compared to unexpanded nanofiber scaffolds, more CD68+ and CD163+ cells were observed within expanded scaffolds at all tested time points post-implantation. More CCR7+ cells appeared within expanded scaffolds at week 8 post-implantation. In addition, new blood vessels were present within the expanded scaffolds at week 2. The formed multinucleated giant cells within expanded scaffolds were heterogeneous expressing CD68, CCR7, or CD163 markers. Together, the present study demonstrated that the expanded nanofiber scaffolds promoted cellular infiltration/tissue integration, a regenerative response, and neovascularization after subcutaneous implantation in rats. The use of expanded electrospun nanofiber scaffolds offers a promising method for in situ tissue repair/regeneration and generation of three-dimensional tissue models/constructs.

Living nanofiber yarn-based woven biotextiles for tendon tissue engineering using cell tri-culture and mechanical stimulation

“…Electrospun nanofibrous scaffolds or nano/micro hybrid constructions have been demonstrated to promote cell adhesion, proliferation, and differentiation for tendon tissue engineering applications [27–30]. However, such non-woven constructs also have several limitations that prevent broader clinical application [31–33]. The tightly packed fibrous structure, small pore sizes existing between fibers (usually below 3 μm), and inferior controllability of fiber organization may limit cell growth, migration, and infiltration into the inner layers, and are not beneficial for the transportation of oxygen and nutrients throughout the implant site and removal of metabolic waste during tissue regeneration.…”

Three-dimensional nanofiber scaffolds with arrayed holes for engineering skin tissue constructs

“…4). [10,11] The nanofiber membrane was initially 0.4 mm thick and became about 4 mm thick after expansion. Figure 2 shows the morphology of a 3D nanofiber scaffold with arrayed holes.…”

“…Recently, our group has developed a modified gas-foaming technique to expand 2D nanofiber membranes in the third dimension with controlled thickness and highly porous structures. [10,11] It was also demonstrated that cells can infiltrate the expanded nanofiber scaffolds and proliferate within the nanofiber scaffolds. These promising results motivated us to fabricate a novel type nanofiber skin graft for chronic wound healing.…”

“…[13] In order to prepare a highly hydrophilic 3D nanofibrous scaffold, we punched arrayed holes throughout 2D scaffolds and then transformed 2D membranes into 3D nanofiber scaffolds using a modified gas-foaming technique. [10,11] To demonstrate the proof-ofconcept, green fluorescent protein-labeled human dermal fibroblasts (GFP-HDF) cell spheroids were prepared and seeded into the arrayed holes of 3D nanofiber scaffolds. The cell adhesion and migration were examined in vitro.…”

“…The nanofiber mats with arrayed holes were then expanded to form 3D scaffolds using a modified gas-foaming technique following our established protocols. [10,11] Briefly, the nanofiber mats were immersed in freshly prepared 1% NaBH 4 solutions at room temperature for 5-30 min. The expanded scaffolds were then gently rinsed three times with distilled water for 10 min each and finally freeze-dried overnight.…”