title: *Hierarchically Structured Electrospun Scaffolds with Chemically Conjugated Growth Factor for Ligament Tissue Engineering.
abstract: The anterior cruciate ligament (ACL) of the knee is vital for proper joint function and is commonly ruptured during sports injuries or car accidents. Due to a lack of intrinsic healing capacity and drawbacks with allografts and autografts, there is a need for a tissue-engineered ACL replacement. Our group has previously used aligned sheets of electrospun polycaprolactone nanofibers to develop solid cylindrical bundles of longitudinally aligned nanofibers. We have shown that these nanofiber bundles support cell proliferation and elongation and the hierarchical structure and material properties are similar to the native human ACL. It is possible to combine multiple nanofiber bundles to create a scaffold that attempts to mimic the macroscale structure of the ACL. The goal of this work was to develop a hierarchical bioactive scaffold for ligament tissue engineering using connective tissue growth factor (CTGF)-conjugated nanofiber bundles and evaluate the behavior of mesenchymal stem cells (MSCs) on these scaffolds in vitro and in vivo. CTGF was immobilized onto the surface of individual nanofiber bundles or scaffolds consisting of multiple nanofiber bundles. The conjugation efficiency and the release of conjugated CTGF were assessed using X-ray photoelectron spectroscopy, assays, and immunofluorescence staining. Scaffolds were seeded with MSCs and maintained in vitro for 7 days (individual nanofiber bundles), in vitro for 21 days (scaled-up scaffolds of 20 nanofiber bundles), or in vivo for 6 weeks (small scaffolds of 4 nanofiber bundles), and ligament-specific tissue formation was assessed in comparison to non-CTGF-conjugated control scaffolds. Results showed that CTGF conjugation encouraged cell proliferation and ligament-specific tissue formation in vitro and in vivo. The results suggest that hierarchical electrospun nanofiber bundles conjugated with CTGF are a scalable and bioactive scaffold for ACL tissue engineering.
authors.affiliation: 1 School of Biomedical Engineering, Colorado State University , Fort Collins, Colorado.
authors.forename: Hannah M
authors.initials: HM
authors.lastname: Pauly
authors.affiliation: 2 Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute , Trinity College Dublin, Dublin, Ireland .
authors.forename: Binulal N
authors.initials: BN
authors.lastname: Sathy
authors.affiliation: 2 Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute , Trinity College Dublin, Dublin, Ireland .
authors.forename: Dinorath
authors.initials: D
authors.lastname: Olvera
authors.affiliation: 3 School of Pharmacy, Queen's University Belfast , Belfast, United Kingdom .
authors.forename: Helen O
authors.initials: HO
authors.lastname: McCarthy
authors.affiliation: 2 Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute , Trinity College Dublin, Dublin, Ireland .|4 Department of Mechanical and Manufacturing Engineering, School of Engineering, Trinity College Dublin , Dublin, Ireland .|5 Department of Anatomy, Royal College of Surgeons in Ireland , Dublin, Ireland .|6 Advanced Materials and Bioengineering Research Centre, Royal College of Surgeons in Ireland and Trinity College Dublin , Dublin, Ireland .
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Kelly
authors.affiliation: 1 School of Biomedical Engineering, Colorado State University , Fort Collins, Colorado.|7 Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado.
authors.forename: Ketul C
authors.initials: KC
authors.lastname: Popat
authors.affiliation: 2 Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute , Trinity College Dublin, Dublin, Ireland .|3 School of Pharmacy, Queen's University Belfast , Belfast, United Kingdom .|8 Centre for Medical Engineering Research, School of Mechanical and Manufacturing Engineering, Dublin City University , Dublin, Ireland .
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Dunne
authors.affiliation: 1 School of Biomedical Engineering, Colorado State University , Fort Collins, Colorado.|7 Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado.
authors.forename: Tammy Lynn
authors.initials: TL
authors.lastname: Haut Donahue
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000494:pharmacology*; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D057139:Nanofibers / Q000737:chemistry / Q000648:ultrastructure; D019919:Prosthesis Implantation; D012756:Sheep; D040521:Subcutaneous Tissue / Q000187:drug effects; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D055513:Connective Tissue Growth Factor; D003094:Collagen
keywords: growth factor; knee; ligament; polymer; scaffold