3D-microfibers improve the shear modulus of hydrogel composites

Conference Dates

June 5-9, 2017


A major challenge in the field of biofabrication is to manufacture a construct soft enough to elicit optimal cell behavior while possessing the mechanical properties required to withstand the complex in-vivo mechanical environment [1]. Hydrogels that were reinforced with polycaprolactone (PCL) fibers arranged in box structures, obtained by melt electrospinning writing (MEW), showed a synergistic increase in the compressive Young’s modulus [2], however, collapsed in-vivo, possibly due to shear stress. Here, we used MEW to produce specifically designed PCL fibers to stabilize an existing structure and subsequently improve the shear modulus of hydrogel-fiber composites. Instrument parameters affecting fabrication of these fibers were studied and stabilizing fibers used for shear testing (fiber diameter = 13.16 ± 0.11 μm) were made with an amplitude of 500 μm, wavelength of 400 μm, and collector velocity of 400 mm/min, at a height of 20 layers (330 m) (Figure 1A). The stabilizing fibers were embedded in 5, 10, and 15 wt.% polyacrylamide and a frequency sweep test (0.05 – 500 rad/s, 0.01% strain, n = 5) was performed to measure the complex shear modulus of the hydrogel-fiber composites. To correspond the direction of the stabilizing fibers with the torque of the rheometer, stabilizing fibers were printed in a specific architecture (Figure 1B). Stabilizing fibers increased the complex shear modulus by 148%, 127%, and 165%, when embedded within a 5%, 10%, and 15% polyacrylamide hydrogel, respectively (Figure 1C). This study highlights the capacity of MEW to increase shear properties of matrix-fiber composites through inclusion of stabilizing fibers.

Please click Additional Files below to see the full abstract.

This document is currently not available here.