Emulsion-templated porous polymers as scaffolds for three dimensional cell culture: Effect of synthesis parameters on scaffold formation and homogeneity

Emulsion-templated porous polymers (PolyHIPEs) based on polystyrene have been prepared and used for in vitro 3D cell culture of osteoblastic cells. It has been found that the method employed to prepare the emulsion precursor, namely the method of aqueous phase addition, has a significant influence on the homogeneity of the morphology of the material produced as well as the reproducibility of preparation. Addition of the aqueous phase in a controlled manner by means of a syringe pump produced a narrower void size distribution range than addition from a dropping funnel, and the emulsions were obtained in a reproducible manner. Analysis of the morphology of the materials revealed consistency of average void and interconnect diameter, within certain limits. The materials produced were subsequently sectioned into thin membranes which were then mounted to the base of commercially available tissue culture plastic well inserts. Cell culture experiments using MG63 osteoblast-like cells indicated that the materials were capable of supporting cell growth for periods of up to 35 days, producing complex arrangements of cells interacting with one another and the scaffold. The functionality of cells grown on these materials, as indicated by viability assays and the production of biomarkers (alkaline phosphatase and osteocalcin), was found to be enhanced compared to cells grown on 2D substrates. We conclude that the 3D environment produced by these porous materials is more conducive to cell growth in vitro than existing 2D culture plastic.