Fig. 4.

CaP formation begins after 2 days in culture for silica-coated mouse islets. EDS analysis confirms initial formation of a silica deposit followed by growth of a CaP mineral layer upon incubation in RPMI. Concentration of the elements Si, Ca, and P at the encapsulated murine islet surface after 4 h (n = 7), 1 day (n = 4), 2 days (n = 9), 4 days (n = 9), 7 days (n = 7), and 14 days (n = 4) of incubation are shown vs. time in culture. Point source scans at CaP nodules at 4 days (n = 9), 7 days (=4), and 14 days (n = 8) show an increasing Ca/P ratio (inset) (atomic% ± SE).