Spherical capsules were prepared by extruding aqueous agarose-gelation conjugate solution into co-flowing liquid paraffin at 38 degrees C and cooling the resultant emulsion. Capsule diameter was controlled between 40 and 250 mu m by changing the velocity of the liquid paraffin. Adherent Crandall-Reese feline kidney cells enclosed in conjugate capsules of 141 +/- 23 mu m diam. had a higher degree of proliferation than those in unmodified agarose capsules. Mitochondrial activity, detected for cell-enclosing conjugate capsules normalized against unit volume of gel, was about double that of unmodified agarose capsules over 28 days. These results demonstrated the feasibility of agarose-gelatin conjugate as a material of cell-enclosing capsules.