The present invention provides novel metal alginates prepared from non-cross-linked alginate monomers such as sodium alginate and an aqueous solution of a group 4, 5, or 6 metal oxyhalide. The novel group 4, 5, and 6 metal alginates are useful in the preparation of cell culture supports, exhibit useful X-ray contrast properties, and exhibit unanticipated stability to standard autoclave conditions relative to known metal alginates such as calcium alginate. In general, the novel metal alginates provided by the present invention offer features and properties not observed in known metal alginates such as calcium or barium alginates.
