Methods and compositions for exosome isolation

Abstract

Disclosed are methods, compositions and kits for the isolation of exosomes from biological fluids and tissues. Volume-excluding polymers are used to precipitate exosomes from biological samples thereby allowing exosome isolation by low-speed (benchtop) centrifugation or filtration. Further fractionation of exosomes after precipitation is also described.

1 . A method for the isolation of exosomes from a biological fluid sample comprising:
 a) adding a volume-excluding polymer to the biological fluid sample,   b) incubating the biological fluid sample with the volume-excluding polymer; and   c) isolating the precipitated exosomes from the biological fluid sample.   
     
     
         2 . The method of  claim 1 , wherein the molecular weight of the volume-excluding polymer is from 1000 to 1,000,000 daltons. 
     
     
         3 . (canceled) 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the concentration of volume-excluding polymer upon mixing with the biological fluid is from 1% to 90%. 
     
     
         6 . The method of  claim 5 , wherein the concentration of volume-excluding polymer upon mixing with the biological fluid is from 3% to 15%. 
     
     
         7 . (canceled) 
     
     
         8 . The method of  claim 1 , further comprising the step of clarifying the biological fluid sample before adding the volume-excluding polymer. 
     
     
         9 . The method of  claim 1  further comprising the step of isolating nucleic acid and protein from the exosomes. 
     
     
         10 . The method of  claim 1 , wherein the biological fluid is from prokaryotes, eukaryotes, bacteria, fungi, yeast, invertebrates, vertebrates, reptiles, fish, insects, plants or animals. 
     
     
         11 . The method of  claim 1 , wherein the biological fluid is selected from the group consisting of blood serum, plasma, whole blood, urine, saliva, breast milk, tears, sweat, joint fluid, cerebrospinal fluid, semen, vaginal fluid, ascitic fluid, amniotic fluid, and cell culture media. 
     
     
         12 . (canceled) 
     
     
         13 . The method of  claim 1 , further comprising fractionating the isolated exosomes. 
     
     
         14 . The method of  claim 1 , wherein the volume-excluding polymer is polyethylene glycol, dextran, dextran sulfate, dextran acetate, polyvinyl alcohol, polyvinyl acetate, or polyvinyl sulfate. 
     
     
         15 . (canceled) 
     
     
         16 . The method of  claim 1 , further comprising contacting the biological fluid sample prior to the addition of the volume-excluding polymer with a protease, under conditions suitable for digestion of protein. 
     
     
         17 . (canceled) 
     
     
         18 . A method for the isolation of exosomes from a biological tissue sample comprising:
 a) lysing the biological tissue sample,   b) clarifying the lysed sample   c) adding a volume-excluding polymer to the clarified sample,   d) incubating the clarified sample with the volume-excluding polymer, and   e) isolating the precipitated exosomes.   
     
     
         19 . The method of  claim 18 , wherein the molecular weight of the volume-excluding polymer is from 1000 to 1,000,000 daltons. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . The method of  claim 18 , wherein the concentration of volume-excluding polymer upon mixing with the biological sample is from 1% to 90%. 
     
     
         23 . The method of  claim 22 , wherein the concentration of volume-excluding polymer upon mixing with the biological sample is from 3% to 15%. 
     
     
         24 . (canceled) 
     
     
         25 . The method of  claim 18 , wherein the volume-excluding polymer is polyethylene glycol, dextran, dextran sulfate, dextran acetate, polyvinyl alcohol, polyvinyl acetate, or polyvinyl sulfate. 
     
     
         26 . (canceled) 
     
     
         27 . The method of  claim 18  further comprising the step of isolating nucleic acid and protein from the exosomes. 
     
     
         28 . The method of  claim 18 , wherein the biological sample is from prokaryotes, eukaryotes, bacteria, fungi, yeast, invertebrates, vertebrates, reptiles, fish, insects, plants or animals. 
     
     
         29 . The method of  claim 18 , wherein the biological sample is selected from the group consisting of surgical samples, biopsy samples, tissues, feces, plant tissue, insect tissue, fungi, bacteria, parasites and cultured cells. 
     
     
         30 . The method of  claim 18 , further comprising contacting the biological tissue sample with a protease, under conditions suitable for digestion of protein, prior to the addition of the volume-excluding polymer. 
     
     
         31 . (canceled)