title: Three-Dimensional Microgel Platform for the Production of Cell Factories Tailored for the Nucleus Pulposus.
abstract: Intradiscal injection of growth factors or cells has been shown to attenuate symptoms of intervertebral disc degeneration. However, different approaches are needed to overcome limitations such as short-term efficacy and leakage of the injected solutions. The current study aims at creating a platform for the realization of functional cell factories by using in parallel cell delivery and gene therapy approaches. Superfect, a transfecting agent, was used as nonviral gene vector because of its ability to form complexes with plasmid DNA (polyplexes). Polyplexes were loaded into collagen hollow microsphere reservoirs, and their ability to transfect cells was ascertained in vitro. Adipose-derived stem cells were then embedded in three-dimensional (3D) microgels composed of type II collagen/hyaluronan, which mimics the environmental cues typical of the healthy nucleus pulposus. These were functionalized with polyplex-loaded collagen hollow spheres and the secretion of the target protein was assessed quantitatively. Delivery of polyplexes from a reservoir system lowered their toxicity significantly while maintaining high levels of transfection in a monolayer culture. In 3D microgels, lower levels of transfection were observed, however; increasing levels of luciferase were secreted from the microgels over 7 days of culture. These results indicate that 3D microgels, functionalized with polyplex-loaded reservoirs offer a reliable platform for the production of cell factories that are able to manufacture targeted therapeutic proteins for regenerative therapies that have applications in nucleus pulposus repair.
authors.affiliation: †Network of Excellence for Functional Biomaterials and ‡Anatomy, National University of Ireland, Galway, Ireland.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Fontana
authors.affiliation: †Network of Excellence for Functional Biomaterials and ‡Anatomy, National University of Ireland, Galway, Ireland.
authors.forename: Akshay
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: †Network of Excellence for Functional Biomaterials and ‡Anatomy, National University of Ireland, Galway, Ireland.
authors.forename: Dilip
authors.initials: D
authors.lastname: Thomas
authors.affiliation: †Network of Excellence for Functional Biomaterials and ‡Anatomy, National University of Ireland, Galway, Ireland.
authors.forename: Pierce
authors.initials: P
authors.lastname: Lalor
authors.affiliation: †Network of Excellence for Functional Biomaterials and ‡Anatomy, National University of Ireland, Galway, Ireland.
authors.forename: Peter
authors.initials: P
authors.lastname: Dockery
authors.affiliation: †Network of Excellence for Functional Biomaterials and ‡Anatomy, National University of Ireland, Galway, Ireland.
authors.forename: Abhay
authors.initials: A
authors.lastname: Pandit
mesh_terms: D000818:Animals; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D024043:Collagen Type II / Q000737:chemistry*; D004247:DNA / Q000008:administration & dosage; D006820:Hyaluronic Acid / Q000737:chemistry*; D007403:Intervertebral Disc / Q000502:physiology; D010957:Plasmids / Q000008:administration & dosage; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D054457:Tissue Scaffolds / Q000737:chemistry*; D014162:Transfection / Q000379:methods
chemical_list: D024043:Collagen Type II; D006820:Hyaluronic Acid; D004247:DNA