Analysis of void shape and size in the collector plate and polycaprolactone molecular weight on electrospun scaffold pore size

Abstract

Many variations in the electrospinning process have emerged to control pore size needed in tissue scaffolds including introducing voids in the collector plate. However, the effect of different shapes and sizes of voids on fiber and pore sizes is not well understood. In this study, we evaluated the effect of void size and shapes in the collector plate on polycaprolactone (PCL) fiber size and pore size. First, we performed experiments using three different sizes of circular voids (0.9, 1.4, and 1.9 cm). Also, we evaluated the effect of triangular and rectangular voids. Further, changes in the electrical field within the voids were evaluated using computational fluid dynamic software COMSOL. Fibers using mixtures of PCL (high, medium, and low molecular weight) formed using void collector plate and performed degradation characteristics for 30 days in physiological conditions (37 C and 7.4 pH). These results showed that the size and the morphology of fibers are not affected by the geometrical patterns of the voids. However, fiber alignment is affected by the void shape due to favorable rearrangement in the electrical field. Fibers can be formed by mixing PCL of different molecular weight, and degradation of PCL fiber was accelerated by the mixture with low molecular weight. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 1583-1591, 2013

Rapid prototyping of a miniaturized Electrospinning setup for the production of polymer nanofibers

“…The plots generated for both collector configurations [Figure (b)] demonstrate that the electric field vectors diverge from the positively biased tip electrode and converge toward the corners of the grounded collector electrodes. This suggests that charged fibers would be ejected from the tip electrode and electrostatically drawn toward the corners of the collector following the highest potential gradient and shortest distance to the collector electrodes . Once a part of the fiber is immobilized on the collecting electrode, we expect the electrostatic interactions within the highly charged fibers and external electric fields exerted on these fibers to play a major role in positioning, stretching, and aligning the remainder of the fiber.…”

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

“…29 This enhanced the effective driving force, thus permitting the collection of thickness-tunable scaffolds with an intact, highly porous fiber structure resulting from the void space in the aluminum foil. 25 In addition, electrospun fibers were interconnected with the existing fibers through the voids in the aluminum foil layers because the solvent did not fully evaporate inside or on the surface of the electrospun fiber layers. Thus, these highly porous and interconnected electrospun fibers accumulated through the voids within the stacked aluminum foil of the collector.…”

“…25 The basic equation used in the simulation was the Laplacian equation: where φ is the electric potential. All assumptions and boundary conditions were based on the experimental electrospinning setup.…”

Influence of scaffold forming techniques on stress relaxation behavior of polycaprolactone scaffolds

“…Significant advances have been made in synthesizing porous scaffolds of precise size and shape . Scaffolds have been generated using PCL by various additive techniques such as electrospinning, rapid prototyping, and subtractive techniques such as salt leaching, freeze drying, and modified melt processing with selective extraction . Electrospinning produces non‐woven fibers of diameters ranging from nanometers to micrometer.…”

“…The objective of this study was to understand the effect of scaffold preparation techniques on the viscoelastic properties of low and high MW PCL. The scaffolds of 45 and 80 kDa MW were prepared using salt leaching technique and electrospinning technique . The effect of processing of the scaffolds in relaxation property was investigated.…”