Polymeric sequence probe for single DNA detection.

A polynucleotide probe, polymeric sequence probe (PSP), was developed for single molecular detections. PSP is a single-stranded DNA molecule with ~2000 tandem repeat target-binding sequences and label-binding sequences. A single PSP can bind to multiple fluorescent complementary oligos to generate a strong fluorescence signal. Single target molecules bound to PSPs can be clearly visualized by a conventional fluorescence microscope. An ultrasensitive PSP-based assay for Mycobacterium tuberculosis was demonstrated.