title: Carbon-based hierarchical scaffolds for myoblast differentiation: Synergy between nano-functionalization and alignment.
abstract: While several scaffolds have been proposed for skeletal muscle regeneration, multiscale hierarchical scaffolds with the complexity of extracellular matrix (ECM) haven't been engineered successfully. By precise control over nano- and microscale features, comprehensive understanding of the effect of multiple factors on skeletal muscle regeneration can be derived. In this study, we engineered carbon-based scaffolds with hierarchical nano- and microscale architecture with controlled physico-chemical properties. More specifically, we built multiscale hierarchy by growing carbon nanotube (CNT) carpets on two types of scaffolds, namely, interconnected microporous carbon foams and aligned carbon fiber mats. Nanostructured CNT carpets offered fine control over nano-roughness and wettability facilitating myoblast adhesion, growth and differentiation into myocytes. However, microporous foam architecture failed to promote their fusion into multinucleated myotubes. On the other hand, aligned fibrous architecture stimulated formation of multinucleated myotubes. Most importantly, nanostructured CNT carpets interfaced with microscale aligned fibrous architecture significantly enhanced myocyte fusion into multinucleated mature myotubes highlighting synergy between nanoscale surface features and micro-/macroscale aligned fibrous architecture in the process of myogenesis.
  
  
  CONCLUSIONS
  Due to limited regenerative potential of skeletal muscle, strategies stimulating regeneration of functional muscles are important. These strategies are aimed at promoting differentiation of progenitor cells (myoblasts) into multinucleated myotubes, a key initial step in functional muscle regeneration. Recent tissue engineering approaches utilize various scaffolds ranging from decellularized matrices to aligned biomaterial scaffolds. Although, majority of them have focused on nano- or microscale organization, a systematic approach to build the multiscale hierarchy into these scaffolds is lacking. Here, we engineered multiscale hierarchy into carbon-based materials and demonstrated that the nanoscale features govern the differentiation of individual myoblasts into myocytes whereas microscale alignment cues orchestrate fusion of multiple myocytes into multinucleated myotubes underlining the importance of multiscale hierarchy in enhancing coordinated tissue regeneration.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors.forename: Akhil
authors.initials: A
authors.lastname: Patel
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors.forename: Shilpaa
authors.initials: S
authors.lastname: Mukundan
authors.affiliation: Center for Nanoscale Multifunctional Materials, Mechanical & Materials Engineering, Wright State University, Dayton, OH 45324, United States.
authors.forename: Wenhu
authors.initials: W
authors.lastname: Wang
authors.affiliation: Center for Nanoscale Multifunctional Materials, Mechanical & Materials Engineering, Wright State University, Dayton, OH 45324, United States.
authors.forename: Anil
authors.initials: A
authors.lastname: Karumuri
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States.
authors.forename: Vinayak
authors.initials: V
authors.lastname: Sant
authors.affiliation: Center for Nanoscale Multifunctional Materials, Mechanical & Materials Engineering, Wright State University, Dayton, OH 45324, United States.
authors.forename: Sharmila M
authors.initials: SM
authors.lastname: Mukhopadhyay
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, United States. Electronic address: shs149@pitt.edu.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Sant
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D048430:Cell Shape; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000166:cytology; D032446:Myoblasts / Q000166:cytology* / Q000378:metabolism; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D054457:Tissue Scaffolds / Q000737:chemistry*; D017155:Wettability
chemical_list: D037742:Nanotubes, Carbon
keywords: Alignment; C2C12; Carbon nanotubes; Carbon-based scaffolds; Interconnected microporous structure; Multiscale hierarchy; Myogenesis; Nano-roughness