title: Multivalent dendrimers presenting spatially controlled clusters of binding epitopes in thermoresponsive hyaluronan hydrogels.
abstract: The controlled presentation of biofunctionality is of key importance for hydrogel applications in cell-based regenerative medicine. Here, a versatile approach was demonstrated to present clustered binding epitopes in an injectable, thermoresponsive hydrogel. Well-defined multivalent dendrimers bearing four integrin binding sequences and an azido moiety were covalently grafted to propargylamine-derived hyaluronic acid (Hyal-pa) using copper-catalyzed alkyne-azide cycloaddition (CuAAC), and then combined with pN-modified hyaluronan (Hyal-pN). The dendrimers were prepared by synthesizing a bifunctional diethylenetriamine pentaacetic acid core with azido and NHBoc oligo(ethylene glycol) aminoethyl branches, then further conjugated with solid-phase synthesized RGDS and DGRS peptides. Azido terminated pN was synthesized by reversible addition-fragmentation chain transfer polymerization and reacted to Hyal-pa via CuAAC. Nuclear magnetic resonance (NMR), high performance liquid chromatography, size exclusion chromatography and mass spectroscopy proved that the dendrimers had well-defined size and were disubstituted. NMR and atomic absorption analysis confirmed the hyaluronan was affixed with dendrimers or pN. Rheological measurements demonstrated that dendrimers do not influence the elastic or viscous moduli of thermoresponsive hyaluronan compositions at a relevant biological concentration. Finally, human mesenchymal stromal cells were encapsulated in the biomaterial and cultured for 21days, demonstrating the faculty of this dendrimer-modified hydrogel as a molecular toolbox for tailoring the biofunctionality of thermoresponsive hyaluronan carriers for biomedical applications.
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland; Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Seelbach
authors.affiliation: Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Baldiri Reixac 10-12, 08028 Barcelona, Spain.
authors.forename: Peter
authors.initials: P
authors.lastname: Fransen
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland.
authors.forename: Marianna
authors.initials: M
authors.lastname: Peroglio
authors.affiliation: Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Baldiri Reixac 10-12, 08028 Barcelona, Spain; Combinatorial Chemistry Unit, Barcelona Science Park, Baldiri Reixac 10-12, 08028 Barcelona, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pulido
authors.affiliation: Institute de Quimica de Sarría, Via Augusta 390, 08017 Barcelona, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Lopez-Chicon
authors.affiliation: Universitätsklinik Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Duttenhoefer
authors.affiliation: Universitätsklinik Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Sauerbier
authors.affiliation: Universitätsklinikum Goethe Universität, Schleusenweg 2-16, D-60538 Frankfurt am Main, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Freiman
authors.affiliation: Universitätsklinik Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Niemeyer
authors.affiliation: Institute de Quimica de Sarría, Via Augusta 390, 08017 Barcelona, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Semino
authors.affiliation: Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain; Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Baldiri Reixac 10-12, 08028 Barcelona, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Albericio
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland.
authors.forename: Mauro
authors.initials: M
authors.lastname: Alini
authors.affiliation: Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Baldiri Reixac 10-12, 08028 Barcelona, Spain; Combinatorial Chemistry Unit, Barcelona Science Park, Baldiri Reixac 10-12, 08028 Barcelona, Spain.
authors.forename: Miriam
authors.initials: M
authors.lastname: Royo
authors.affiliation: Queen Mary, University of London, Mile End Road, E1 4NS London, UK.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Mata
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos Platz, Switzerland. Electronic address: david.eglin@aofoundation.org.
authors.forename: David
authors.initials: D
authors.lastname: Eglin
mesh_terms: D018914:Cells, Immobilized / Q000166:cytology / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D050091:Dendrimers / Q000138:chemical synthesis / Q000737:chemistry*; D000939:Epitopes / Q000737:chemistry*; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry*; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D044968:Regenerative Medicine / Q000379:methods
chemical_list: D050091:Dendrimers; D000939:Epitopes; D020100:Hydrogels; D006820:Hyaluronic Acid
keywords: Engineered microenvironments; Human mesenchymal stem cells; Hyaluronan; Injectable hydrogels; Multivalent dendrimers