Abstract
Purpose: :
To optimize and evaluate an in vitro, three dimensional, retina culture model using primary photoreceptor cells encapsulated in polymer-based scaffolds. We hypothesize that increased stiffness of the hydrogel constructs may increase cell viability and photoreceptor specific protein expression of retinal cells.
Methods: :
Cells were isolated from the retina of Nrl-GFP mice at post natal stage P4 and encapsulated in poly(ethylene glycol) polymer (PEG). Ultraviolet light was used to photopolymerize the polymer to form a solid gel. The constructs used a range of 10% to 20% weight to volume ratio of PEG in conjunction with 5% to 10% laminin, known for aiding neural development. Cultured for up to 10 days, the gels were evaluated using live/dead viability assays at two time points. GFP expression was also measured at these time points.
Results: :
Gel constructs with a higher weight to volume ratio of polymer exhibited increased cell viability during the culturing period compared to gels with lower weight to volume ratio of polymer. The GFP expression, at earlier time points, was increased in gels with higher weight to volume polymer ratios. Regardless of the amount of polymer, gel constructs that included laminin showed an increase in cell viability in comparison to those without laminin.
Conclusions: :
Increased cell survival in PEG constructs with higher weight to volume polymer ratio and the increase in GFP expression at the earlier time point suggest that stiffer scaffolding may provide a better environment for photoreceptor growth. These results indicate potential benefits of stiffer polymer-based scaffolds for the in vitro culture of photoreceptors.