Regeneration of the Nucleus Pulposus using “smart” Hydrogels
For this study, which was funded by the Hansjörg Wyss start-up award, a papain-cavity model in the center of the IVD, developed within our group, was used. In the cavity, a thermo-reversible polyamide [poly(N-isopropylacrylamide), pNIPAM, developed and patented by David Eglin and colleagues at the AO Research Institute] along with human mesenchymal stem cells for nucleus pulposus (NP) regeneration have been tested. This start-up project revealed that injected stem cells can indeed survive in this cell-friendly hydrogel and that they start to differentiate towards IVD precursor cells after 7 days of loading. However, MRI T2* mapping and mechanical tests demonstrated that the mechanical sustainability of NP replacement hydrogels would need to be improved for the long term.