Processing polynucleotide-containing samples

Abstract

Methods and systems for processing polynucleotides (e.g., DNA) are disclosed. A processing region includes one or more surfaces (e.g., particle surfaces) modified with ligands that regain polynucleotides under a first set of conditions (e.g., temperature and pH) and release the polynucleotides under a second set of conditions (e.g., higher temperature and/or more basic pH). The processing region can be used to, for example, concentrate polynucleotides of a sample and/or separate inhibitors of amplification reactions from the polynucleotides. Microfluidic devices with a processing region are disclosed.

1 - 23 . (canceled) 
     
     
         24 . A method comprising:
 introducing a sample solution into a first processing region of a microfluidic device, wherein the sample solution comprises polynucleotides bound to a plurality of magnetic binding particles, the binding particles having polycationic ligands bound to the surfaces thereof, wherein the sample solution in the first processing region has a first pH of about 9.5 or less;   heating the sample solution and the plurality of magnetic binding particles within the first processing region, wherein the microfluidic device is thermally associated with a heat source configured to operate the first processing region; and   releasing a nucleic acid sample from the binding particles by contacting the binding particles with a release solution characterized by a pH greater than 10.   
     
     
         25 . The method of  claim 24 , further comprising moving the nucleic acid sample to an amplification chamber within the microfluidic device. 
     
     
         26 . The method of  claim 25 , further comprising heating the amplification chamber with one or more amplification heat sources in thermal communication with the amplification chamber. 
     
     
         27 . The method of  claim 25 , further comprising isolating the amplification chamber with valves. 
     
     
         28 . The method of  claim 25 , further comprising detecting the presence of amplified polynucleotides in the amplification chamber. 
     
     
         29 . The method of  claim 24 , further comprising moving a solution through the first processing region and into a waste chamber. 
     
     
         30 . The method of  claim 24 , further comprising moving a wash solution through the first processing region prior to moving the release solution into first processing region. 
     
     
         31 . The method of  claim 24 , wherein the polycationic ligands comprise at least one of poly-DL-ornithine, poly-L-lysine, and poly-D-lysine. 
     
     
         32 . The method of  claim 24 , wherein the heat source is integral with an operating system which operates the microfluidic device during use. 
     
     
         33 . The method of  claim 24 , wherein the plurality of magnetic binding particles are prevented from passing downstream of the first processing region. 
     
     
         34 . A method comprising:
 introducing a sample solution into a first processing region of a microfluidic device, wherein the sample solution comprises polynucleotides bound to a plurality of magnetic binding particles, the binding particles having polycationic ligands bound to the surfaces thereof, wherein the binding particles are configured to preferentially bind polynucleotides in the sample solution at a first pH and release the polynucleotides at a second pH, wherein the first pH is about 9.5 or less, wherein the second pH is about 10 or greater;   heating the sample solution and plurality of magnetic binding particles within the first processing region, wherein the microfluidic device is thermally associated with a heat source configured to operate the first processing region; and   releasing a nucleic acid sample from the binding particles by contacting the binding particles with a release solution.   
     
     
         35 . The method of  claim 34 , further comprising moving the nucleic acid sample to an amplification chamber within the microfluidic device. 
     
     
         36 . The method of  claim 35 , further comprising heating the amplification chamber with one or more amplification heat sources in thermal communication with the amplification chamber. 
     
     
         37 . The method of  claim 35 , further comprising isolating the amplification chamber with valves. 
     
     
         38 . The method of  claim 35 , further comprising detecting the presence of amplified polynucleotides in the amplification chamber. 
     
     
         39 . The method of  claim 34 , further comprising moving a solution through the first processing region and into a waste chamber. 
     
     
         40 . The method of  claim 34 , further comprising moving a wash solution through the first processing region prior to moving the release solution into first processing region. 
     
     
         41 . The method of  claim 34 , wherein the polycationic ligands comprise at least one of poly-DL-ornithine, poly-L-lysine, and poly-D-lysine. 
     
     
         42 . The method of  claim 34 , wherein the heat source is integral with an operating system which operates the microfluidic device during use. 
     
     
         43 . The method of  claim 34 , wherein the plurality of magnetic binding particles are prevented from passing downstream of the first processing region.