Recent advances in probe amplification technologies

Oligonucleotide probes provide a useful tool for the detection of target nucleic acids by the formation of a double helical structure between complementary sequences. The stringent requirements of Watson-Crick base pairing make hybridization extremely specific. However, the detection of target sequence by hybridization is often insensitive due to the limited number of signal molecules that can be labeled on the probe. In general, the analytical sensitivity of probe hybridization is of the order 10⁶ molecules. Therefore, it cannot meet the needs of most clinical diagnostic applications. Many technologies have been developed to improve the detection sensitivity by amplifying the probe sequence bound to the target. All probe amplification technologies are developed based on the recent advancement in molecular biology and the understanding of in vivo nucleic acid synthesis (i.e., ligation, polymerization, transcription, digestion/cleavage, etc.).