A metal-containing polyaledehyde microsphere composed of a polyaldehyde microsphere to which a transition metal, e.g. Au, Ag, Pt, Pd, Tc, Fe, Ni or Co, is bound may be obtained in accordance with this invention. The polyaldehyde, e.g. polyacrolein or polyglutaraldehyde, may be encapsulated in agarose, and the mocrosphere may be radioactive or magnetic. The microphere may additionally have a compound having at least one amine group, e.g. a drug, antibody, antigen, enzyme or other protein, bound to its surface.
In one embodiment a transition metal is bound to a polyaldehyde microsphere by contacting the polyaldehyde microsphere with a suitable amount of an appropriate salt or acid of the transition metal under suitable conditions so as to cause the salt or acid to be reduced to a lower valence state and to bind to the microsphere. Some salts or acids may thus be reduced to the elemental state; others are further reduced with an appropriate reducing agent.
In another embodiment, a transition metal in elemental form is bound to a polyaldehyde microsphere by contacting the polyaldehyde microsphere with a suitable amount of a compound capable of complexing with a salt or acid of the transition metal under suitable conditions permitting binding of the compound to the microsphere, contacting the compound with an appropriate amount of an appropriate salt or acid of a transition metal under appropriate conditions permitting the compound to bind to the salt or acid, and reducing the salt or acid to the corresponding elemental metal by contacting it under effective reducing conditions and for a sufficient period of time with a sufficient amount of an effective reducing agent. The metal-containing microsphere of this invention is useful for such applications as cell labeling, cell separation, diagnostic methods, catalysis and coating methods.