Binding a target substance

Abstract

Magnetic particles capable of binding a target substance, which comprise a magnetic material and a matrix material, wherein the magnetic material is remanent upon exposure to a magnetic field and the matrix material has a surface comprising functional groups which promote disaggregation of the particles in the presence of a liquid phase.

1 - 55 . (canceled) 
     
     
         56 . Magnetic particles capable of binding a target substance, the magnetic particles comprising a magnetic material and a matrix material, wherein the magnetic material is remanent upon exposure to a magnetic field such that the magnetic material has a residual magnetization that is sufficient to cause the magnetic particles to form aggregates when suspended in a liquid phase in the absence of a magnetic field but are dispersible upon application of a force to disrupt the aggregates, wherein the matrix material has a surface comprising functional groups that promote disaggregation of the particles in the presence of a liquid phase, and wherein the magnetic particles are not paramagnetic or superparamagnetic. 
     
     
         57 . Magnetic particles according to  claim 56 , wherein the magnetic material comprises a magnetic metal oxide. 
     
     
         58 . Magnetic particles according to  claim 57 , wherein the magnetic metal oxide comprises an iron oxide in which, optionally, all or a part of the ferrous iron thereof is substituted by a divalent transition metal selected from cadmium, chromium, cobalt, copper, magnesium, manganese, nickel, vanadium, and/or zinc. 
     
     
         59 . Magnetic particles according to  claim 56 , wherein the magnetic material comprises a ferrimagnetic metal oxide. 
     
     
         60 . Magnetic particles according to  claim 59 , wherein the ferrimagnetic metal oxide comprises ferrimagnetic magnetite. 
     
     
         61 . Magnetic particles according to  claim 56 , wherein the magnetic material comprises a ferromagnetic material. 
     
     
         62 . Magnetic particles according to  claim 56 , the length or diameter of which is in the range 0.1 to 5000 μm. 
     
     
         63 . Magnetic particles according to  claim 56 , which are substantially spherical. 
     
     
         64 . Magnetic particles according to  claim 56 , wherein the matrix material comprises a polymer. 
     
     
         65 . Magnetic particles according to  claim 64 , wherein the polymer comprises an organic polymer or a silica-based polymer. 
     
     
         66 . Magnetic particles according to  claim 56  wherein the functional groups of the matrix material are hydrophilic for use with an aqueous liquid phase. 
     
     
         67 . Magnetic particles according to  claim 56 , wherein the functional groups of the matrix material are hydrophobic for use with a non-polar liquid phase. 
     
     
         68 . Magnetic particles according to  claim 56 , wherein the matrix material further comprises an affinant for binding the target substance. 
     
     
         69 . Magnetic particles according to  claim 56 , wherein the target substance is a protein. 
     
     
         70 . Magnetic particles according to  claim 68 , wherein the affinant is capable of binding a cell, a protein, a virus or a prion. 
     
     
         71 . Magnetic particles according to  claim 70 , wherein the affinant comprises an antibody, a binding protein, a fragment of an antibody or binding protein, or a ligand. 
     
     
         72 . Magnetic particles according to  claim 71 , wherein the affinant comprises a binding protein which comprises an avidin for binding to a target substance which is biotinylated, or the affinant comprises biotin and the target substance is avidinylated. 
     
     
         73 . Magnetic particles according to  claim 71 , wherein the affinant comprises a ligand which comprises a metal chelate specific for the target substance. 
     
     
         74 . Magnetic particles according to  claim 70 , wherein the cell or protein is microbial. 
     
     
         75 . Magnetic particles according to  claim 68 , wherein the target substance comprises a metal and the affinant comprises a chelator for the metal. 
     
     
         76 . Magnetic particles according to  claim 67 , wherein the hydrophobic functional groups are capable of binding microorganisms or hydrophobic target substances. 
     
     
         77 . A process for separating a target substance from a target substance containing sample, which comprises:
 (a) providing target substance binding magnetic particles which comprise a magnetic material and a matrix material, wherein the magnetic material is remnant upon exposure to a magnetic field such that the magnetic material has residual magnetization that is sufficient to cause the magnetic particles to form aggregates when suspended in a liquid phase in the absence of a magnetic field but are dispersible upon application of a force to disrupt the aggregates, wherein the magnetic particles are not paramagnetic or superparamagnetic, and wherein the matrix material has a surface comprising functional groups that promote disaggregation of the magnetic particles in the presence of a liquid phase;   (b) providing a liquid phase comprising the target substance-containing sample;   (c) dispersing the sample with the magnetic particles so as to allow the magnetic particles to bind the target substance thereto by disrupting magnetic particles to disaggregate the magnetic particles; and   (d) isolating the magnetic particles from the sample by applying a magnetic field thereto and separating the particles from the liquid phase.