Superparamagnetic pearl polymers

Abstract

The invention relates to cross-linked pearl polymers doped with superparamagnetic iron oxide, to a method for producing said pearl polymers, and to their use in nucleic acid diagnostics.

1 - 10 . (cancelled)  
     
     
         11 . A process for preparing superparamagnetic bead polymers, comprising: 
 (a) polymerizing a monomer mixture comprising hydrophilic (meth)acrylate and amino(meth)acrylate to form bead polymers;    (b) contacting the bead polymers with a sufficient amount of an iron salt solution to form the superparamagnetic iron oxide bead polymers.    
     
     
         12 . The process of  claim 11 , wherein the polymerization reaction is conducted with a crosslinker.  
     
     
         13 . The process of  claim 12 , wherein the crosslinker is selected from the group consisting of ethylene glycol dimethacrylate, butanediol dimethacrylate, hexanediol dimethacrylate, pentaerytritol dimethacrylate, 1,2-glycerin-dimethacrylate, 1,3-glycerin-dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylol propane trimethacrylate, pentaerytritol trimethacrylate, pentaerytritol tetramethacrylate, ethylene glycol diacrylate, butanediol diacrylate, pentaerytriol diacrylate, 1,3-glycerin-diacrylate, triethylene glycol diacrylate, trimethylol propane triacrylate, pentaerytritol triacrylate, pentaerytritol tetraacrylate, allyl methacrylate, allyl acrylate, diethylene glycol divinyl ether, and methylene-N,N′-bisacrylamide.  
     
     
         14 . The process of  claim 11  wherein the hydrophilic (meth)acrylates are those whose homopolymers have a solubility of more than 2.5% in water at 25° C.  
     
     
         15 . The process of  claim 14 , wherein the hydrophilic (meth)acrylates are selected from the group consisting of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, triethylene glycol monomethacrylate, tetraethylene glycol monomethacrylate, glycerol monomethacrylate, acrylamide, methacrylamide, and N,N-dimethyl acrylamide.  
     
     
         16 . The process of  claim 11 , wherein the amino (meth)acrylates are derivatives of acrylic acid and (meth)acrylic acid.  
     
     
         17 . The process of  claim 16 , wherein the amino (meth)acrylates contain secondary and tertiary amino groups.  
     
     
         18 . The process of  claim 17 , wherein the amino groups are part of a cycloaliphatic or aromatic ring.  
     
     
         19 . The process of  claim 11  wherein the amino (meth)acrylates are selected from the group consisting of N-(3-amino-propyl) methacrylamide, N-(3-imidazoylpropyl) methacrylamide, N-(2-imidazoylethyl) methacrylamide, N-(3-aminopropyl) acrylamide, N-(3-imidazoylpropyl) acrylamide, N-(2(2-imidazoylethyl) acrylamide, N-(1(1,1-dimethyl-3-imidazoylpropyl) methacrylamide, N-(1,1-dimethyl-3-imidazoylpropyl) acrylamide, N-(3-benzimidazoylpropyl) methacrylamide, and (3-benzimidazoylpropyl) acrylamide.  
     
     
         20 . The process of  claim 11 , wherein the superparamagnetic bead polymers have a particle size of about 1 to about 200 microns.  
     
     
         21 . The process of  claim 11 , wherein the particle size distribution of the bead polymers is less than or equal to 2.5.  
     
     
         22 . The process of claim  1 , wherein the bead polymers have a swelling index of about 1.25 to about 8, measured at 25° C.  
     
     
         23 . The process of  claim 11 , wherein the polymerization is conducted by means of inverse suspension polymerization.  
     
     
         24 . The process pf  claim 11 , wherein the monomer mixture is diluted with water or water/alcohol mixtures.  
     
     
         25 . The process of  claim 24 , wherein the amount of diluent varies from about 10 to about 200% by weight of the monomer mixture.  
     
     
         26 . The process of  claim 11 , wherein the polymerization temperature varies from about 50° to about 150° C.  
     
     
         27 . The process of  claim 24 , wherein the bead polymer is separated after the polymerization step.  
     
     
         28 . The process of  claim 11 , wherein the bead polymer is fractionated to adjust its particle size distribution.  
     
     
         29 . The process of  claim 28 , wherein the fractionation is accomplished by means selected from the group consisting of screening, sedimentation and air classification.  
     
     
         30 . The process of  claim 12 , wherein the contacting of the crosslinked bead polymers with an iron salt solution is accomplished by doping with superparamagnetic iron oxide in the form of aqueous mixtures of Fe +2  and Fe +3  salt solutions.  
     
     
         31 . The process of  claim 30 , wherein the Fe +2 :Fe +3  molar ratio varies from about 2:1 to about 1:2, respectively.  
     
     
         32 . The process of  claim 27 , wherein the cross linked bead polymers are dried to an anhydrous state before being contacted with the iron salt solution.  
     
     
         33 . The process of  claim 32 , wherein the anhydrous, crosslinked bead polymers absorb the salt solution by swelling, with no excess iron salt solution remaining in the interstices of the beads or on the surface of the beads.  
     
     
         34 . The process of  claim 33 , wherein the iron salts absorbed by the swollen bead polymers are converted into the corresponding iron hydroxides by contacting with bases selected from the group consisting of alkaline solutions of sodium hydroxide, sodium carbonate, or ammonium.  
     
     
         35 . The process of  claim 34 , wherein the iron hydroxide is converted into iron oxide by heating the bead polymers to a temperature in aqueous suspension of about 65 to 100° C.  
     
     
         36 . A method for isolating nucleic acids from a biological sample selected from the group consisting of cells, tissue materials, blood, and pathogens comprising: 
 (a) contacting the sample with a superparamagnetic bead polymers formed by the process of  claim 11 , at a pH of 7.0 or below, to adsorb the nucleic acids;    (b) separating the bead polymers with the adsorbed nucleic acids by using a magnetic field;    (c) contacting the separated bead polymers with water at a pH above 7.0, thereby releasing the adsorbed nucleic acids.    
     
     
         37 . The method of  claim 36 , wherein the biological sample is disrupted to form a lysate prior to the isolation of the nucleic acids.