Use of beads to improve nucleotide hybridization assays

Abstract

This invention utilizes beads in sample preparation to increase the precision of nucleotide hybridization assays.

What is claimed: 
     
       1. A method for separating a pellet area from a supernatant in a centrifugation step in a nucleotide hybridization assay, wherein said method comprises: (a) providing a liquid sample containing a target nucleic acid;   (b) adding a bead to said liquid sample, wherein said bead is not bound to an antibody;   (c) centrifuging said liquid sample to form a supernatant and pellet, wherein said pellet comprises said bead;   (d) identifying the pellet area by the presence of said bead; and   (e) removing the supernatant from the pellet area.   
     
     
       2. The method of claim 1, wherein said bead is colored. 
     
     
       3. The method of claim 2, wherein a plurality of beads are added to said liquid sample. 
     
     
       4. The method of claim 3, wherein the diameter of said beads is substantially between 0.1 μm and 1 μm. 
     
     
       5. The method of claim 4, wherein the density of said beads is substantially between 1.01 and 1.09 g/ml. 
     
     
       6. The method of claim 5, wherein said beads comprise polystyrene. 
     
     
       7. The method of claim 6, wherein said liquid sample comprises target nucleic acids having substantial sequence identity to a viral sequence selected from the group consisting of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), human T-cell leukemia virus-1, and cytomegalovirus (CVM). 
     
     
       8. The method of claim 6, wherein the sample comprises target nucleic acids having substantial sequence identity to a genomic sequence from the group consisting of Chlamydia and Mycobacteria tuberculosis. 
     
     
       9. A centrifuged pellet for a nucleotide hybridization assay comprising a bead and a covalently linked target nucleic acid. 
     
     
       10. A pellet of claim 9, wherein said bead is colored. 
     
     
       11. A pellet of claim 10, wherein said pellet comprises a plurality of beads. 
     
     
       12. A pellet of claim 11, wherein the diameter said beads are substantially between 0.1 μm to 1 μm. 
     
     
       13. The pellet of claim 12, wherein said target nucleic acid having substantial sequence identity to a viral sequence selected from the group consisting of human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus (HCV), human T-cell leukemia virus-1, and cytomegalovirus (CMV). 
     
     
       14. The pellet of claim 12, wherein said target nucleic acids having substantial sequence identity to a genomic sequence from the group consisting of Chlamydia and Mycobacteria tuberculosis.