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 . 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.  
   
   
       2 . Magnetic particles according to  claim 1 , wherein the magnetic material comprises a magnetic metal oxide.  
   
   
       3 . Magnetic particles according to  claim 2 , 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.  
   
   
       4 . Magnetic particles according to  claim 1 , wherein the magnetic material comprises a ferrimagnetic material.  
   
   
       5 . Magnetic particles according to  claim 4 , wherein the ferrimagnetic metal oxide comprises ferrimagnetic magnetite.  
   
   
       6 . Magnetic particles according to  claim 1 , wherein the magnetic material comprises a ferromagnetic material.  
   
   
       7 . Magnetic particles according to  claim 1 , the length or diameter of which is in the range 0.1 to 5000 μm.  
   
   
       8 . Magnetic particles according to  claim 1 , which are substantially spherical.  
   
   
       9 . Magnetic particles according to  claim 1 , wherein the matrix material comprises a polymer.  
   
   
       10 . Magnetic particles according to  claim 9 , wherein the polymer comprises an organic polymer or a silica-based polymer.  
   
   
       11 . Magnetic particles according to  claim 1  wherein the functional groups of the matrix material are hydrophilic for use with an aqueous liquid phase.  
   
   
       12 . Magnetic particles according to  claim 1 , wherein the functional groups of the matrix material are hydrophobic for use with a non-polar liquid phase.  
   
   
       13 . Magnetic particles according to  claim 1 , wherein the matrix material further comprises an affinant for binding the target substance.  
   
   
       14 . Magnetic particles according to  claim 1 , wherein the target substance is a nucleic acid.  
   
   
       15 . Magnetic particles according to  claim 13 , wherein the affinant is capable of binding a cell, a protein, a virus or a prion.  
   
   
       16 . Magnetic particles according to  claim 15 , wherein the affinant comprises an antibody, a binding protein, a fragment of an antibody or binding protein, or a ligand.  
   
   
       17 . Magnetic particles according to clam 16, 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.  
   
   
       18 . Magnetic particles according to  claim 16 , wherein the affinant comprises a ligand which comprises an oligonucleotide or a metal chelate specific for the target substance.  
   
   
       19 . Magnetic particles according to  claim 15 , wherein the cell or protein is microbial.  
   
   
       20 . Magnetic particles according to  claim 13 , wherein the target substance comprises a metal and the affinant comprises a chelator for the metal.  
   
   
       21 . Magnetic particles according to  claim 12  wherein the hydrophobic functional groups are capable of binding microorganisms or hydrophobic target substances.  
   
   
       22 . A process for the preparation of magnetic particles capable of binding a target substance, which comprises providing an unmagnetised magnetic material, and providing a matrix material so as to form magnetic particles, 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.  
   
   
       23 . A process according to  claim 22 , wherein the matrix material comprises a polymer.  
   
   
       24 . A process according to  claim 23 , wherein the polymer comprises an organic polymer or a silica-based polymer.  
   
   
       25 . A process according to  claim 22 , wherein the matrix material is provided preformed and added to the magnetic material.  
   
   
       26 . A process according to  claim 24 , wherein the polymer is provided by polymerisation of a monomer in the presence of the unmagnetised magnetic material to form the magnetic particles comprising the magnetic material and a polymeric material.  
   
   
       27 . A process according to  claim 26 , wherein the monomer comprises an organic monomer or a silica-based monomer.  
   
   
       28 . A process according to  claim 26  or  claim 27 , wherein the step of polymerisation comprise a step growth condensation and/or a radical reaction.  
   
   
       29 . A process according to  claim 26 , wherein the step of polymerisation takes place in an emulsion and the unmagnetised magnetic material is present in a discontinuous phase of the emulsion.  
   
   
       30 . A process according to  claim 29 , wherein the step of polymerisation takes place in the discontinuous phase of the emulsion.  
   
   
       31 . A process according to  claim 29  or claim  claim 29 , wherein the monomer is present in a continuous phase of the emulsion, prior to polymerisation.  
   
   
       32 . A process according to  claim 31 , wherein the monomer comprises an organic monomer and the emulsion is a water-in-oil emulsion.  
   
   
       33 . A process according to  claim 31 , wherein the monomer comprises a silica-based monomer and the emulsion is an oil-in-water emulsion.  
   
   
       34 . A process according to  claim 26 , wherein the step of polymerisation takes place in a solution.  
   
   
       35 . A process according to  claim 22 , wherein the magnetic material comprises particles, the length or diameter of which is in the range 100 to 300 nm.  
   
   
       36 . A process according to  claim 22 , wherein the magnetic particles are 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.  
   
   
       37 . Use of magnetic particles according to  claim 1 , for separating a target substance from a sample containing such a target substance.  
   
   
       38 . Use of magnetic particles according to  claim 1 , for separating a target substance comprising a cell, a microorganism, or a protein from a sample containing such a target substance.  
   
   
       39 . Use of magnetic particles according to  claim 1 , for separating a target substance comprising a metal from a sample containing such a target substance.  
   
   
       40 . Use of magnetic particles according to  claim 1 , for separating a target substance comprising an organic compound from a sample containing such a target substance.  
   
   
       41 . Use of magnetic particles according to  claim 1 , for separating a target substance comprising a nucleic acid from a sample containing such a target substance.  
   
   
       42 . Use according to  claim 37 , wherein the target substance is isolated from the sample.  
   
   
       43 . Use according to  claim 37 , wherein the target substance is depleted from the sample.  
   
   
       44 . Use of magnetic particles according to  claim 1 , in a cell sorting apparatus.  
   
   
       45 . 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;    (b) providing a liquid phase comprising the target substance-containing sample;    (c) dispersing the sample with the magnetic particles so as to bind the target substance thereto; and    (d) isolating the particles from the sample by applying a magnetic field thereto and separating the particles from the liquid phase.    
   
   
       46 . A process according to  claim 45 , wherein the step of dispersing the sample with the magnetic particles comprises subjecting the magnetic particles to disruption to disaggregate the particles.  
   
   
       47 . A process according to  claim 46 , wherein the disruption comprises mechanical disruption selected from pipetting, stirring, vortexing and/or shaking, sonication or UV disruption.  
   
   
       48 . A process according to  claim 45 , wherein the magnetic particles are 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.  
   
   
       49 . A process according to  claim 45 , wherein the magnetic particles are 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, and the target substance comprises a cell, a microorganism, or a protein.  
   
   
       50 . A process according to  claim 45 , wherein the magnetic particles are 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, and the target substance comprises a metal.  
   
   
       51 . A process according to  claim 45 , wherein the magnetic particles are 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, and the target substance comprises an organic compound.  
   
   
       52 . A process according to  claim 45 , wherein the magnetic particles are 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, and the target substance comprises a nucleic acid.  
   
   
       53 . A process according to  claim 52 , wherein the sample comprises unfractionated nucleic acid.  
   
   
       54 . A process according to  claim 45 , wherein the target substance is isolated from the sample.  
   
   
       55 . A process according to  claim 45 , wherein the target substance is a contaminant which is depleted from the sample.