Microparticles from glycidylmethacrylated gelatin as cell carriers prepared in an aqueous two-phase system

Encapsulation by polymeric biomaterials can provide mechanical protection of cells and shielding from the immune system of the host when implanted as cell therapy. At the same time, free exchange of nutrients and metabolites including bioactive molecules guiding regenerative processes is facilitated. Here, glycidylmetha-crylated gelatin (GMA-gelatin) is explored as matrix material for adherent (L929 mouse fibroblasts) or non-adherent (Ramos blue) cells by an integrated process of shaping and chemical crosslinking. Microparticle formation was driven by a water-in-water-emulsion technique, which allowed simultaneous irradiation with light of 365 nm in the presence of the photosensitizer irgacure 2959. Suitable photopolymerization conditions were determined in experiments with GMA-gelatin and cells. More than 85% of the cells survived this procedure, and an encapsulation efficiency of up to 75 +/- 2% was reached. Diffusivity of molecules up to a molar mass of 150 kg.mol(-1) in the matrix was shown by the release of co-encapsulated FITC-labelled dextran. L929 as well as Ramos blue cells proliferated in the microparticle matrix after encapsulation and released enzymes that could be detected in the cell culture medium in an active form. L929 showed the ability to escape the particles over time. Altogether, the presented cell encapsulation system based on a material that is stable to hydrolytic degradation for several weeks is generally suitable for cell based therapy or in vitro test systems.

Automated summary

Encapsulation using GMA-gelatin as matrix material, combined with shaping and chemical crosslinking, successfully achieved microparticle encapsulation of adherent and non-adherent cells. Results showed that over 85% of cells survived under specific photopolymerization conditions and an encapsulation efficiency of around 75% was reached. The study also demonstrated the diffusivity of molecules in the matrix, as well as the proliferation and enzyme release of encapsulated cells in the microparticle matrix.