The effect of crosslinking time and nanoparticle content on electroactive, multi-component scaffolds

Several coaxial electrospun scaffolds containing poly(ε-caprolactone), multi-walled carbon nanotubes (MWCNT), and a poly(acrylic acid)/poly(vinyl alcohol) hydrogel (PCL-MWCNT-PAA/PVA) were created for skeletal muscle regeneration. Although these scaffolds supported myocytes, their mechanical properties were significantly higher than natural muscle and did not significantly degrade over time. Therefore, shorter crosslinking times and lower MWCNT amounts were examined. Shorter PAA/PVA crosslinking times did not significantly effect the properties thus, gelation time was investigated. Average gelation time for 83/17 and 40/60 PAA/PVA solutions were 14.45±7.27 and 1.98±0.78 minutes. We hypothesize that the unaffected mechanical properties is due to evaporation of the crosslinking solution instead of soaking time. Mechanical properties of scaffolds with lower MWCNT amounts were also not significantly different thus suggesting, that even lower amounts must be utilized to alter mechanical properties. Conversely, lower amounts of MWCNT did not affect scaffold actuation speeds. Due to the unaltered mechanical properties, platinum nanoparticles (Pt Np) replaced the MWCNT in the scaffold. PCL-Pt scaffolds were more conductive, 0.054±0.016 S/cm, but the mechanical properties were similar to MWCNT containing scaffolds. Further studies will focus on decreasing the Pt Np and PCL amounts to better match the properties of skeletal muscle.