The invention describes the manufacture and use of secretory cell containing bead structures that are coated with agarose. The beads, which are preferably 4 mm-12 mm in diameter, and which preferably contain islets, are made of a particular agarose, i.eagarose which has a sulfate content of less than 0.2 wt % but greater than zero, a pyruvate content of 0-0.1 wt %, and a Kjeldahl nitrogen content of 0-0.04 wt %. The gels found from the agarose exhibit a gel strength of at least 1200 g/cm2 (1.0 wt % concentration), substantial absence of DNA binding in 0.07 M or less tris acetate buffer, and an EEO at 1.0 wt % agarose concentration of 0.05 or less.
