Triple-helical capture assay for quantification of polymerase chain reaction products.

This method for rapid, automated analysis of polymerase chain reaction (PCR) products makes use of PCR primers containing 5'-polypyrimidine sequences. Polypyrimidine-"headed" primers confer to the PCR product the ability to form triple helical complexes with a third polypyrimidine oligonucleotide. Third-strand oligonucleotides are modified to serve as either capture reagents or detection reagents for PCR products. Automated quantitative measurement of the PCR product is achieved by using latex bead-based fluorescence analysis. The use of triple-instead of double-helical interactions avoids the usual requirements of complex blocking reagents, time- and labor-intensive washing steps, and long times for color development. The method also provides rapid, sequence-specific capture and detection of PCR products without the need to denature the double-stranded PCR product. The assay is demonstrated with use of both PCR primer-derived and endogenous triple-helix-forming sequences resulting from PCR of several bacterial and viral target nucleic acids.