Metal–Electrolyte Solution Dual‐Mode Electrospinning Process for In Situ Fabrication of Electrospun Bilayer Membrane

Abstract

vivo extracellular matrix (ECM). [2] Various advantages of the electrospun nanofiber membranes, including broad material selection, a high surface-area-to-volume ratio, controllability of physical properties (e.g., diameter and orientation of the nanofibers and porosity and thickness of the membrane), and capability in fabrication of complex nanostructures (e.g., coreshell and Janus nanofibers), [3] have made remarkable advancements in the development of in vitro tissue models and in vivo tissue regeneration. [1,2] Many studies have tried to control the spatial orientation of the electrospun nanofibers through electrospinning, given that the cellular activities, such as adhesion, migration, proliferation, and differentiation, could be promoted by the contact guidance through an anisotropic topographical cue of the electrospun nanofibers. Among various approaches to control the orientation of the electrospun nanofibers, including the electric fieldassisted method, rotating drum method, and magnetic electrospinning, [4-6] the electric field-assisted method readily modulates the orientation of the electrospun nanofibers in a precise and versatile manner. Based on the electric field-assisted method, previous studies have achieved various types of membranes from a uniaxially aligned nanofiber membrane to radially, circumferentially, and biaxially aligned nanofiber membranes, [6-8] showing their potential in manipulating many cell functions, such as myogenic differentiation of myoblast, dural fibroblast migration, and tight junction formation of endothelial cells. [9-11] However, the aligned nanofiber membrane produced by the electric field-assisted method is mechanically unstable, in general, because of its thin (<30 µm thick), anisotropic, and sparsely interconnected nanofibrous structures. [12-14] Hence, the aligned nanofiber membrane is prone to be damaged by external forces occurred with the experimental and surgical manipulations and the aqueous conditions during in vitro and in vivo biomedical applications. [9,15,16] An innovative approach to overcome such limitations of the aligned nanofiber membranes is to develop an electrospun bilayer membrane, also known as a kind of Janus sheet, composed of two membranes, one aligned and the other random, which simultaneously provide the anisotropic topographical Electrospun bilayer membranes comprising two layers, one aligned and the other random, have shown great potential in tissue engineering but previous fabrication processes inevitably relied on manual integration and produced limited types of membranes. Here, a metal-electrolyte solution dual-mode electrospinning (M-ELES) for fabrication of electrospun bilayer membrane based on a metal-electrolyte solution switchable collector is developed. The switchable collector enables random nanofiber deposition directly over the preexisting aligned nanofiber layer in an in situ manner and integration of the layers through an on-demand switch from the metal to the electrolyte solution collector. The electrolyte solution can eff...

Robust Topographical Micro-Patterning of Nanofibrillar Collagen Gel by In Situ Photochemical Crosslinking-Assisted Collagen Embossing

“…Our results showed that the micro-ridge patterns on the IPC-CE construct favorably promoted both the elongation and orientation of cells along the micro-ridges by geometrical confinement, which stably maintained their structure during the cell culture period, whereas the conventional constructs lost their topographical effect following rehydration. Although in the present study, we considered only a simple in vitro cell culture, the proposed IPC-CE construct may have various biomedical applications, such as the development of an in vitro model for mimicking the hierarchical topography of native tissues and a scaffold/wound dressing for promoting in vivo tissue regeneration [ 36 , 37 ]. Moreover, given that the attachment, alignment, and elongation of cells resulted from their sensing and response to the surrounding cell environment [ 38 , 39 ], a more profound understanding of in vivo cell-surface topography interactions may be accomplished from in-depth investigations of cell behaviors on micro-patterned constructs with in vivo-like collagen nanofibrillar architectures.…”

Standardized tensile testing of electrospun PA6 membranes via the use of a 3D printed clamping system

“…Therefore, a number of membranes were wetted with a physiological solution (sodium chloride (NaCl) 0.9%) and subsequently compared to the dry membranes. Three tensile test scenarios were selected for which the strain rate was set at 10 mm/min: 26–28 a standard metal clamp, a paper frame and the new clamp were tested and compared so as to observe their effectiveness and their measurement reproducibility ( n = 12). As the jaws were designed for the more rapid clamping of samples, the time required for the placing of samples in the paper frame, including the time required to prepare the paper frame, were compared with the time required for the placing of samples in the printed jaws.…”

Improved Chondrogenic Performance With Protective Tracheal Design of Chitosan Membrane Surrounding 3D-Printed Trachea

“…Each end of the specimen was gripped in a clamp and its tensile properties was tested at a constant tensile speed of 10 mm min − 1 , using a customized testing machine comprising a linear actuator and a load cell with a resolution of 0.01 gf. [18] The resultant force-distance curve was converted to a stress-strain curve for evaluating the elastic modulus, ultimate tensile strength, and resilience.…”