Hydroxyethyl methacrylate-methyl methacrylate (HEMA-MMA) copolymers for cell microencapsulation: Effect of HEMA purity

Thermoplastic copolymers of 2-hydroxyethyl methacrylate (HEMA) and methyl m ethacrylate (MMA) (molar ratio: 75/25 HEMA-MMA) were synthesized using HEMA containing different amounts of ethylene glycol dimethacrylate (EGDMA) to investigate their suitability for cell microencapsulation. Pure HEMA (0.0% EGDMA) was obtained with preparative chromatography to prepare a linear cop olymer. Microcapsules (with a diameter of 300-400 mu m) were readily made w ith the copolymers by interfacial precipitation. Smaller and more transpare nt capsules were obtained using the copolymer prepared from purer HEMA. Chi nese hamster ovary (CHO) fibroblasts, as model cells, were microencapsulate d in the linear copolymer. The CHO cells survived the microencapsulation pr ocess and the metabolic activity of the encapsulated cells increased within the 14 days observation period.