title: Cell encapsulation in a magnetically aligned collagen-GAG copolymer microenvironment.
abstract: Engineered tissue microenvironments impart specialized cues that drive distinct cellular phenotypes and function. Microenvironments with defined properties, such as mechanical properties and fibril alignment, can elicit specific cellular responses that emulate those observed in vivo. Collagen- and glycosaminoglycan (GAG)-based tissue matrices have been popularized due to their biological ubiquity in a broad range of tissues and the ability to tune structure and mechanical properties through a variety of processes. Here, we investigate the combined effects of static magnetic fields, and GAG and cell encapsulation, on the structure (e.g. collagen fibril orientation) and material properties of collagen matrices. We found that magnetic fields align the collagen-GAG matrix, alter equilibrium mechanical properties and provide a method for encapsulating cells within a three-dimensional aligned matrix. Cells are encapsulated prior to polymerization, allowing for controlled cell density and eliminating the need for cell seeding. Increased relative GAG concentrations reduced the ability to magnetically align collagen fibrils, in part through a mechanism involving increased viscosity and polymerization time of the collagen-GAG solution. This work provides a functional design space for the development of pure collagen and hybrid collagen-GAG matrices in the presence of magnetic fields. Additionally, this work shows that magnetic fields are effective for the fabrication of collagen constructs with controlled fibril orientation, and can be coupled with GAG incorporation to modulate mechanical properties and the response of embedded cells.
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Tyler
authors.initials: T
authors.lastname: Novak
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA; Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Sherry L
authors.initials: SL
authors.lastname: Voytik-Harbin
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA. Electronic address: cpneu@purdue.edu.
authors.forename: Corey P
authors.initials: CP
authors.lastname: Neu
mesh_terms: D000818:Animals; D040761:Biomimetic Materials / Q000138:chemical synthesis; D002417:Cattle; D049109:Cell Proliferation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D060833:Cellular Microenvironment / Q000502:physiology* / Q000528:radiation effects; D019902:Chondrocytes / Q000166:cytology* / Q000502:physiology; D003094:Collagen / Q000737:chemistry* / Q000528:radiation effects; D019245:Compressive Strength / Q000502:physiology / Q000528:radiation effects; D055119:Elastic Modulus / Q000502:physiology / Q000528:radiation effects; D005109:Extracellular Matrix / Q000737:chemistry* / Q000145:classification*; D006025:Glycosaminoglycans / Q000737:chemistry*; D060526:Magnetic Fields; D008422:Materials Testing; D040542:Mechanotransduction, Cellular / Q000502:physiology / Q000528:radiation effects; D023822:Tissue Engineering / Q000379:methods*; D014783:Viscosity / Q000528:radiation effects
chemical_list: D006025:Glycosaminoglycans; D003094:Collagen
keywords: Chondrocytes and cartilage; Collagen oligomers; Hyaluronic acid; Magnetic alignment; Tissue engineering microenvironment