title: Rheological and mechanical properties of acellular and cell-laden methacrylated gellan gum hydrogels.
abstract: Tissue engineered hydrogels hold great potential as nucleus pulposus substitutes (NP), as they promote intervertebral disc (IVD) regeneration and re-establish its original function. But, the key to their success in future clinical applications greatly depends on its ability to replicate the native 3D micro-environment and circumvent their limitation in terms of mechanical performance. In the present study, we investigated the rheological/mechanical properties of both ionic- (iGG-MA) and photo-crosslinked methacrylated gellan gum (phGG-MA) hydrogels. Steady shear analysis, injectability and confined compression stress-relaxation tests were carried out. The injectability of the reactive solutions employed for the preparation of iGG-MA and phGG-MA hydrogels was first studied, then the zero-strain compressive modulus and permeability of the acellular hydrogels were evaluated. In addition, human intervertebral disc (hIVD) cells encapsulated in both iGG-MA and phGG-MA hydrogels were cultured in vitro, and its mechanical properties also investigated under dynamic mechanical analysis at 37°C and pH 7.4. After 21 days of culturing, hIVD cells were alive (Calcein AM) and the E' of ionic-crosslinked hydrogels and photo-crosslinked was higher than that observed for acellular hydrogels. Our study suggests that methacrylated gellan gum hydrogels present promising mechanical and biological performance as hIVD cells were producing extracellular matrix.
authors.affiliation: 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, S. Cláudio de Barco, Caldas das Taipas, Guimarães, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Silva-Correia
authors.forename: Antonio
authors.initials: A
authors.lastname: Gloria
authors.forename: Mariana B
authors.initials: MB
authors.lastname: Oliveira
authors.forename: João F
authors.initials: JF
authors.lastname: Mano
authors.forename: Joaquim M
authors.initials: JM
authors.lastname: Oliveira
authors.forename: Luigi
authors.initials: L
authors.lastname: Ambrosio
authors.forename: Rui L
authors.initials: RL
authors.lastname: Reis
mesh_terms: D000328:Adult; D002469:Cell Separation; D002470:Cell Survival / Q000187:drug effects; D005260:Female; D006801:Humans; D020100:Hydrogels / Q000494:pharmacology*; D007403:Intervertebral Disc / Q000166:cytology; D055595:Mechanical Phenomena / Q000187:drug effects*; D008689:Methacrylates / Q000494:pharmacology*; D010539:Permeability / Q000187:drug effects; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D012212:Rheology / Q000187:drug effects*; D013314:Stress, Mechanical; D014783:Viscosity / Q000187:drug effects
chemical_list: D020100:Hydrogels; D008689:Methacrylates; D011135:Polysaccharides, Bacterial; C048288:gellan gum
keywords: hydrogels; injectability; mechanical properties; methacrylated gellan gum; rheology