Magnetic particles and methods of producing coated magnetic particles

Abstract

An improved method for separating materials is provided, using colloidal, magnetizable aggregates, optionally silanized, and coated with a one or more layers of novel polysaccharide derivatives. Materials separated by the aggregates of the invention include inorganic and organic molecules, viruses, organelles, and cells. The invention also relates to a kit for separating such materials. The separated materials are useful in analytical and preparative or in diagnostic and therapeutic techniques.

1 . A method of producing magnetizable particles for separation of a target material, said method comprising the steps of: 
 providing aggregates of crystallites of a magnetizable metal oxide;    coating said aggregates with a polysaccharide derivative having pendant functional groups; and    coupling a coupling group to said functional group to form said magnetizable particles, said coupling group having a binding affinity for said target material and said magnetizable particles being dispersible in a liquid and being separable from a liquid applying a magnetic field.    
   
   
       2 . A method of preparing an aminoarylpolysaccharide or an aminoalkylpolysaccharide, said method comprising the steps of: 
 forming a mixture of a polysaccharide and an alkyl azide or an aryl azide having a reactive functional group spaced from an azide group of said alkyl azide or aryl azide to form an azidopolysaccharide reaction product, and    adding a reducing agent to said azidopolysaccharide reaction product to reduce said azide group and form said aminoalkylpolysaccharide or aminoarylpolysaccharide.    
   
   
       3 . A polysaccharide with pendant carboxyl groups in which the carboxyl group is attached to said polysaccharide through a linker at least four atoms in length and having at least one heteroatom for every three carbon atoms in the linker.