Oriented nanofibrous membranes for tissue engineering applications: Electrospinning with secondary field control

Abstract

Electrospinning is an electrical field driven method to produce polymer fibre membranes by deposition of a charged polymer jet onto a grounded collector. Fibre alignment within these mats is usually achieved by a fast collector movement, which is not feasible for all collector geometries, such as small diameter tubes or free-form moulds. The aim of this study was to evaluate the use of charged deflector plates to apply a dynamic, alternating electrical field perpendicular to the spinning direction, in order to directly control the fibre trajectory. Different field signal types, deflector plate voltages and deflection frequency ranges have been investigated. 210 poly(ɛ)caprolactone (PCL) membranes were electrospun. SEM images of each membrane were analysed using ImageJ. Main fibre diameter and orientation, as well as the degree of fibre alignment, were calculated, while a subset of the spun scaffolds were tested for their tensile properties. Higher deflector plate voltage amplitude resulted in a better fibre alignment. The best alignment was observed in a low deflection frequency range from 2 to 10 Hz. Mean main fibre direction was 87±18°, relative to the deflection axis, while fibre alignment had only a minor effect on the average fibre diameter. Young's modulus and yield stress increased with the ratio of the parallel fibre component. The feasibility of the described method to achieve fibre alignment was demonstrated. However, the main fibre direction is not aligned with the deflection axis, but consistently perpendicular to it, which is also reflected in the tensile properties of spun samples.

Geometric constraints of endothelial cell migration on electrospun fibres

“…Scaffolds were generated using a parallel-plate electrospinning technique with subtle changes to the processing conditions yielding aligned fibres with diameters ranging from 0.5–10 μm. The air gap created between the two parallel electrodes used for scaffold fabrication generates residual electrostatic repulsion resulting in alignment of the charged fibres 17 . The diameter of the electrospun fibres was dependent on variables such as polymer concentration, solvents used and flow rate.…”

Induced Periosteum-Mimicking Membrane with Cell Barrier and Multipotential Stromal Cell (MSC) Homing Functionalities

“…This was of particular interest as cells within periosteum align along the longitudinal axis of bone, following or guiding collagen fibre alignment [ 52 , 53 ], in contrast to BM MSCs, that line the surface of bone [ 54 ]. Thus, the alignment of both periosteal and BM MSCs is a critical advantage as preferential alignment of fibres compromises the isotrophy of membrane tensile strength [ 55 ]. Periosteal MSCs aligned irrespective of cell density, although at a slightly slower rate with lower seeding density, in contrast, BM MSCs preferred alignment with higher seeding density.…”

Effect of the Distribution of Fiber Orientation on the Mechanical Properties of Silk Fibroin/Polycaprolactone Nanofiber Mats

“…The electrostatic spinning equipment was comprised of a high-voltage power supply (FC60P2, Glassman Company, USA) and an injection pump (KDS220, KDS Scientific Co., Ltd., USA). During electrospinning, the diameter of nanofibers was controlled by adjusting spinning parameters, such as the concentration of the spinning solution, the flow rate of the spinning solution, the conductivity of the solvent and the environmental conditions, to obtain electrospun nanofiber mats that met the specified requirements [32]. Based on literature reports [33,34], the electrostatic spinning parameters were as follows: voltage 15 KV, spinning flow rate 1.2 ml/h, drum receiving distance 12 cm, environment temperature 25±2°C, and relative humidity 35±5%.…”