Isolation of nucleic acids on surfaces

Abstract

New processes and equipment to isolate and purify nucleic acids on surfaces are provided. The invention focuses on processes which use surfaces, for example, porous membranes, on which the nucleic acids are immobilized in a simple manner from the sample containing the nucleic acids and can be released again by way of simple procedural steps, whereby the simple performance of the process according to the invention makes it possible to perform the processes specifically in a fully automatic manner. An additional aspect of the present invention focuses on binding the nucleic acids to an immobile phase, especially to a membrane, in such a way and manner, that they can be released without difficulty during an additional reaction stage from this phase and, if desired, can be used in other applications, such as restriction digestion, RT, PCR or RT-PCR, or in any of the suitable analyses or enzyme reactions mentioned in the disclosure. Special isolation devices are provided that can be used to carry out the processes according to the invention.

1 - 76 . (canceled)  
   
   
       77 . A process for isolating nucleic acids comprising the following steps: 
 (a) providing an isolation device with at least one membrane located therein;    (b) applying a nucleic acid-containing sample to the isolation device;    (c) precipitating the nucleic acids contained in the sample with isopropanol, so that the nucleic acids are bound to said membrane, and    (d) releasing the bound nucleic acids from said membrane with an elution agent;    characterized in that said membrane comprises cellulose and has pores that are is equal to or larger than 0.2 micrometer.    
   
   
       78 . The process according to  claim 77 , characterized in that the isopropanol alcohol is added to the nucleic acid-containing sample prior to adding the sample to the isolation device.  
   
   
       79 . The process according to  claim 77 , characterized in that the isopropanol is added to the nucleic acid-containing sample after adding the sample to the isolation device.  
   
   
       80 . The process according to  claim 77 , characterized in that the surface of the membrane is selected so that all the nucleic acids contained in the solution can be bound to the membrane.  
   
   
       81 . (canceled)  
   
   
       82 . The process according to  claim 77 , wherein said nucleic acids precipitated are DNA and/or RNA.  
   
   
       83 . (canceled)  
   
   
       84 . The process according to  claim 77 , wherein the volume ratio of the nucleic acids-containing sample to isopropanol is 2:1 to 1:1.  
   
   
       85 - 92 . (canceled)  
   
   
       93 . The process according to  claim 77 , wherein the membrane consists of cellulose acetate or cellulose nitrate.  
   
   
       94 . The process according to  claim 93 , wherein the membrane has a pore size equal to or more than 0.45 μm.  
   
   
       95 . The process according to  claim 93 , wherein the membrane has a pore size of more than 0.6 μm.  
   
   
       96 - 120 . (canceled)  
   
   
       121 . The process according to any one of claims  77 - 80 ,  82 ,  84 , and  93 - 95 , wherein said elution agent is a solution of a compound selected from the group consisting of water, morpholinopropane sulfonic acid, tris(hydroxymethyl)aminomethane, 2-[4-(2-hydroxymethyl)piperazino]ethane sulfonic acid, an alkaline metal salt, an alkaline-earth metal salt, a carboxylic acid salt, a dicarboxylic acid salt, and combinations thereof.  
   
   
       122 . The process according to any one of claims  77 - 80 ,  82 , and  84 , wherein said isolation device is provided with one or more membranes selected from the group consisting of a cellulose nitrate membrane, a cellulose acetate membrane, and combinations of cellulose nitrate and cellulose acetate membranes.  
   
   
       123 . The process according to  claim 122 , wherein said isolation device is provided with one or more membranes having a pore size selected from the group consisting of 0.45 μm, 0.65 μm, and combinations thereof.  
   
   
       124 . The process according to any one of claims  77 - 80 ,  82 ,  84 , and  93 - 95 , wherein nucleic acids are released from said membrane in step (d) at a final yield of 80% or greater.  
   
   
       125 . The process according to any one of claims  77 - 80 ,  82 ,  84 , and  93 - 95 , wherein nucleic acids are released from said membrane in step (d) at a final yield in a range of 80% to 90%.  
   
   
       126 . The process according to any one of claims  77 - 80 ,  82 ,  84 , and  93 - 95 , wherein nucleic acids are released from said membrane in step (d) at a final yield of 90% or greater.