title: Autonomous osteogenic differentiation of hASCs encapsulated in methacrylated gellan-gum hydrogels.
abstract: Methacrylated gellan-gum (GG-MA) alone and combined with collagen type I (Coll) is suggested here for the first time as a cell-laden injectable biomaterial for bone regeneration. On-chip high-throughput studies allowed rapidly assessing the suitability of 15 biomaterials/media combinations for the osteodifferentiation of human adipose stem cells (hASCs). Hydrogels composed solely of GG-MA (GG100:0Coll) led hASCs from three different donors into the osteogenic lineage after 21days of cell culture, in the absence of any osteogenic or osteoconductive factors. Hydrogels containing more than 30% of Coll promoted increased cellular proliferation and led hASCs into osteogenic differentiation under basal conditions. Studies using isolated individual hydrogels - excluding eventual on-chip crosstalk - and standard biochemical assays corroborated such findings. The formation of focal adhesions of hASCs on GG100:0Coll hydrogels was verified. We hypothesize that the hydrogels osteogenic effect could be guided by mechanotransduction phenomena. Indeed, the hydrogels showed elastic modulus in ranges previously reported as osteoinductive and the inhibition of the actin-myosin contractility pathway impaired hASCs' osteodifferentiation. GG-MA hydrogels also did not promote hASCs' adipogenesis while used in basal conditions. Overall, GG-MA showed promising properties as an innovative and off-the shelf self-inducing osteogenic injectable biomaterial.
  
  
  
  Methacrylated gellan gum (GG-MA) is here suggested for the first time as a widely available polysaccharide to easily prepare hydrogels with cell adhesion properties and capability of inducing the autonomous osteogenic differentiation of human adipose-derived stem cells (hASCs). GG-MA was processed as stand-alone hydrogels or in different combinations with collage type I. All hydrogel formulations elicited the osteogenic differentiation of hASCs, independently of the addition of any osteoconductive or osteogenic stimuli, i.e. in basal/growth medium. Effective cellular adhesion to methacrylated gellan gum hydrogels in the absence of any cell-ligand peptide/protein was here proved for the first time. Moreover, we showed that the encapsulated hASCs underwent osteogenic differentiation due to a mechanotransduction phenomenon dependent on the actin-myosin contractility pathway.
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal; ICVS/3B's PT Government Associated Laboratory, Braga/Guimarães, Portugal.
authors.forename: Mariana B
authors.initials: MB
authors.lastname: Oliveira
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal; ICVS/3B's PT Government Associated Laboratory, Braga/Guimarães, Portugal.
authors.forename: Catarina A
authors.initials: CA
authors.lastname: Custódio
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal; ICVS/3B's PT Government Associated Laboratory, Braga/Guimarães, Portugal.
authors.forename: Luca
authors.initials: L
authors.lastname: Gasperini
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal; ICVS/3B's PT Government Associated Laboratory, Braga/Guimarães, Portugal.
authors.forename: Rui L
authors.initials: RL
authors.lastname: Reis
authors.affiliation: 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence of Tissue Engineering and Regenerative Medicine, Avepark - Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR, Portugal; ICVS/3B's PT Government Associated Laboratory, Braga/Guimarães, Portugal. Electronic address: jmano@dep.uminho.pt.
authors.forename: João F
authors.initials: JF
authors.lastname: Mano
mesh_terms: D050156:Adipogenesis / Q000187:drug effects; D000328:Adult; D000464:Alginates / Q000494:pharmacology; D017609:Barium Compounds / Q000494:pharmacology; D001672:Biocompatible Materials / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D018914:Cells, Immobilized / Q000166:cytology / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004548:Elasticity; D005260:Female; D022001:Focal Adhesions / Q000187:drug effects / Q000378:metabolism; D020723:Glucuronic Acid / Q000494:pharmacology; D006603:Hexuronic Acids / Q000494:pharmacology; D006801:Humans; D020100:Hydrogels / Q000494:pharmacology*; D008689:Methacrylates / Q000494:pharmacology*; D008856:Microscopy, Fluorescence; D008903:Minerals / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D014783:Viscosity; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000464:Alginates; D017609:Barium Compounds; D001672:Biocompatible Materials; D002712:Chlorides; D003432:Cross-Linking Reagents; D006603:Hexuronic Acids; D020100:Hydrogels; D008689:Methacrylates; D008903:Minerals; D011135:Polysaccharides, Bacterial; C024986:barium chloride; C048288:gellan gum; D020723:Glucuronic Acid; D054460:rho-Associated Kinases; D002122:Calcium Chloride
keywords: Adipose-derived stem cells; Hydrogel; Injectable; Methacrylated gellan gum; Osteogenic differentiation