Cultured Schwann cells, neonatal astrocytes or cells dissociated from embryonic cerebral hemispheres were dispersed within poly-[N-(2-hydroxypropyl)-methacrylamide]-based hydrogel matrices by gel entrapment and maintained in vitro for 1-6 days. Glial cells were pre-labelled with Hoechst 33342. Cell differentiation and viability were studied by immunocytochemistry. Up to 15% of Schwann cells initially entrapped within the polymer matrices were immunopositive for the low affinity nerve growth factor receptor, S100, glial fibrillary acidic protein (GFAP) and laminin; up to 10% of pre-labelled astrocytes were immunopositive for GFAP and laminin. Embryonic neurons displayed immunostaining for neurofilaments. Hydrogels containing entrapped Schwann cells were implanted into the rat neocortex. These polymers supported cellular and axonal ingrowth within parts of the polymer matrix.