Abstract
We studied the feasibility of labeling hydrogel scaffolds with a fluorine nanoemulsion for 19F- magnetic resonance imaging (MRI) to enable non-invasive visualization of their precise placement and potential degradation. Hyaluronan-based hydrogels (activated hyaluronan, HA) withincreasing concentrations of fluorine nanoemulsion (V-sense) were prepared to measure thegelation time and oscillatory stress at 1h and 7days after the beginning of gelation. All biomechanical measurements were conducted with an ARES 2 rheometer. Diffusion of fluorine from the hydrogel: Three hydrogels in various Vs to HA volumetric ratios (1:50, 1:10, and 1:5) were prepared in duplicate. Hydrogels were incubated at 37°C. To inducediffusion, three hydrogels were agitated at 1000rpm. 1H and 19F MRI scans were acquired at 1, 3, 7days and 2months after gel preparation on a Bruker Ascend 750 scanner. To quantify fluorine content, scans were analyzed usingVoxel Tracker 2.0. Assessment ofcell viability in vitro and in vivo: Luciferase-positive mouseglial-restricted progenitors (GRPs) were embedded in 0:1, 1:50, 1:10, and 1:5 Vs:HA mixtures (final cell concentration =1 × 107/ml). For the in vitro assay, mixtures were placedin 96-wells plate in triplicate and bioluminescence was measured after1, 3, 7, 14, 21, and 28days. For in vivo experiments, Vs/HA mixtures containing GRPs were injected subcutaneously in SCID mice and BLI was acquired at 1, 3, 7, and 14dayspost-injection. Mixing of V-sense at increasing ratios of 1:50, 1:10, and 1:5 v/v of fluorine/activated hyaluronan (HA) hydrogel gradually elongated the gelation time from 194s for non-fluorinated controls to 304s for 1:5 V-sense:HA hydrogels, while their elastic properties slightly decreased. There was no release of V-sense from hydrogels maintained in stationary conditions over 2months. The addition of V-sense positively affected in vitro survival of scaffolded GRPs in a dose-dependent manner. These results show that hydrogel fluorination does not impair its beneficial properties for scaffolded cells, which may be used to visualize scaffolded GRP transplants with 19F MRI.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.