Nuclear fluorescent probes are very important tool in modern molecular biology, biomedicine and other fields. The current fluorescence technology can not be directly applied to nucleic acid analysis, because the fluorescence of nucleic acid itself is very weak, so nuclear fluorescence probe must be introduced. Many types of fluorescent probes have been established according to the enhancement or quenching of fluorescence intensity of small molecule probes by nucleic acid.
Characteristics of Nuclear Fluorescent Probes
Nuclear fluorescent probes can specifically recognize the target gene sequence according to the principle of base complementary pairing, and combine the signal transduction mechanism at the molecular level to transform the relevant biological information into fluorescent functional nucleic acid molecules. Compared with fluorescent protein probes, nuclear fluorescent probes do not need complex gene manipulation of the target biological system, and can more directly and truly reflect the physiological state of the target system. In addition to having high specificity and high affinity for the target, nuclear fluorescent probes also have the advantages of simple synthesis, low relative molecular weight, high chemical stability, low toxicity, low immunogenicity, controllable program and easy modification of a variety of functional groups or materials. Using the molecular recognition characteristics of nucleic acids, a variety of nuclear fluorescent probes for different types of targets can be designed.
Application of Nuclear Fluorescent Probes
The nucleus is a highly specialized subcellular organelle and the center of information processing and management in the cells of the living organism. In the field of life science, it is very common to use fluorescent probe technology to carry out Bioscience and biomedical research on the nuclei and chromosomes in cells. The commercialized nuclear dyes are Hoechst, PI and DAPI. The principle of Hoechst and DAPI dyes locating to the nucleus is that the dyes can embed and bind with small DNA grooves with at base pairs. They have excellent membrane permeability and DNA binding specificity. However, both of them need ultraviolet excitation, which will damage the cells and cause significant cell autofluorescence. PI dye has poor membrane permeability. It is mainly used for nuclear staining under the condition of cell membrane damage. It will emit red fluorescence after binding with DNA double strand in the nucleus. Therefore, it is often used to distinguish living cells from dead cells.