title: A novel injectable thermoresponsive and cytocompatible gel of poly(N-isopropylacrylamide) with layered double hydroxides facilitates siRNA delivery into chondrocytes in 3D culture.
abstract: Hybrid hydrogels composed of poly(N-isopropylacrylamide) (pNIPAAM) and layered double hydroxides (LDHs) are presented in this study as novel injectable and thermoresponsive materials for siRNA delivery, which could specifically target several negative regulators of tissue homeostasis in cartilaginous tissues. Effectiveness of siRNA transfection using pNIPAAM formulated with either MgAl-LDH or MgFe-LDH platelets was investigated using osteoarthritic chondrocytes. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an endogenous model gene to evaluate the extent of silencing. No significant adverse effects of pNIPAAM/LDH hydrogels on cell viability were noticed. Cellular uptake of fluorescently labeled siRNA was greatly enhanced (>75%) in pNIPAAM/LDH hydrogel constructs compared to alginate, hyaluronan and fibrin gels, and was absent in pNIPAAM hydrogel without LDH platelets. When using siRNA against GAPDH, 82-98% reduction of gene expression was found in both types of pNIPAAM/LDH hydrogel constructs after 6 days of culturing. In the pNIPAAM/MgAl-LDH hybrid hydrogel, 80-95% of GAPDH enzyme activity was reduced in parallel with gene. Our findings show that the combination of a cytocompatible hydrogel and therapeutic RNA oligonucleotides is feasible. Thus it might hold promise in treating degeneration of cartilaginous tissues by providing supporting scaffolds for cells and interference with locally produced degenerative factors.
authors.affiliation: Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Hsiao-Yin
authors.initials: HY
authors.lastname: Yang
authors.affiliation: TNO Materials Solutions, Eindhoven, The Netherlands.
authors.forename: Renz J
authors.initials: RJ
authors.lastname: van Ee
authors.affiliation: TNO Materials Solutions, Eindhoven, The Netherlands.
authors.forename: Klaas
authors.initials: K
authors.lastname: Timmer
authors.affiliation: TNO Materials Solutions, Eindhoven, The Netherlands.
authors.forename: Eric G M
authors.initials: EGM
authors.lastname: Craenmehr
authors.affiliation: Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Julie H
authors.initials: JH
authors.lastname: Huang
authors.affiliation: Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: F Cumhur
authors.initials: FC
authors.lastname: Öner
authors.affiliation: Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands; Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands.
authors.forename: Wouter J A
authors.initials: WJA
authors.lastname: Dhert
authors.affiliation: Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Angela H M
authors.initials: AHM
authors.lastname: Kragten
authors.affiliation: Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands.
authors.forename: Nicole
authors.initials: N
authors.lastname: Willems
authors.affiliation: Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands.
authors.forename: Guy C M
authors.initials: GCM
authors.lastname: Grinwis
authors.affiliation: Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands.
authors.forename: Marianna A
authors.initials: MA
authors.lastname: Tryfonidou
authors.affiliation: TNO Materials Solutions, Eindhoven, The Netherlands.
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Papen-Botterhuis
authors.affiliation: Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: l.b.creemers@umcutrecht.nl.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Creemers
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000737:chemistry; D002478:Cells, Cultured; D019902:Chondrocytes / Q000737:chemistry / Q000502:physiology*; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D006878:Hydroxides / Q000737:chemistry; D008845:Microinjections / Q000379:methods*; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics*; D014162:Transfection / Q000379:methods*
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D005782:Gels; D006878:Hydroxides; D034741:RNA, Small Interfering; C052970:poly-N-isopropylacrylamide
keywords: Chondrocytes; Injectable hydrogel; Layered double hydroxides; Poly(N-isopropylacrylamide); siRNA delivery