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8 May 1995 PORSCHA: a novel homogeneous assay for detection of DNA/RNA
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A novel assay, Pi Overlapping Ring Systems Contained in a Homogeneous Assay (PORSCHA), has been developed which relies upon the change in fluorescent spectral properties that pyrene and its derivatives show as a function of their proximity. When two pyrene rings are sufficiently close such that their pi-systems can overlap during the excited lifetime, an excimer emission centered at 480 nm is observed. When the pi-systems are too far apart for overlap, only monomer emission is observed at 378 nm and 396 nm. Only Angstrom changes in distances are necessary to switch from excimer to monomer emission. Due to its many degrees of freedom, single-stranded DNA adopts a random-coil conformation in solution. When labeled with two pyrene fluorophores and upon binding to its complimentary strand, the excimer intensity changes because the pyrenes may be either closer together or farther apart, corresponding to the reduced degrees of freedom of the double helix. Because the probe does not disturb the system and no separation steps are necessary before detecting the DNA binding, completely reversible, in situ, detection of DNA is possible.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David A. Kidwell "PORSCHA: a novel homogeneous assay for detection of DNA/RNA", Proc. SPIE 2388, Advances in Fluorescence Sensing Technology II, (8 May 1995);

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