In vivo skeletal muscle biocompatibility of composite, coaxial electrospun, and microfibrous scaffolds.

One weakness with currently researched skeletal muscle tissue replacement is the lack of contraction and relaxation during the regenerative process. A biocompatible scaffold that can act similar to the muscle would be a pivotal innovation. Coaxial electrospun scaffolds, capable of movement with electrical stimulation, were created using poly(ɛ-caprolactone) (PCL), multiwalled carbon nanotubes (MWCNT), and a (83/17 or 40/60) poly(acrylic acid)/poly(vinyl alcohol) (PAA/PVA) hydrogel. The two scaffolds were implanted into Sprague-Dawley rat vastus lateralis muscle and compared with a phosphate-buffered saline injection sham surgery and an unoperated control. No complications or adverse effects were observed. Rats were sacrificed on days 7, 14, 21, and 28 postimplantation and biocompatibility assessed using enzymatic activity, fibrosis formation, inflammation, scaffold cellular infiltration, and neovascularization. Serum creatine kinase and lactate dehydrogenase levels were significantly higher in scaffold-implanted rats compared with the control on day 7, but returned to baseline by day 14. Day 7 scaffolds showed significant inflammation and fibrosis that decreased over time. Fibroblasts infiltrated the scaffolds early, but decreased with time, while myogenic cell numbers increased. Neovascularization of both scaffolds occurred as early as day 7. We conclude that the PCL-MWCNT-PAA/PVA scaffolds are biocompatible and suitable for muscle regeneration as myogenic cell growth was supported.