Fluorescence Imaging and Chiral Specific Biological Recognition

Cancer is one of the major diseases threatening human health. Early detection and early treatment are important means to reduce cancer mortality. At present, in many ways of cancer recognition, fluorescence detection has attracted more and more attention due to its advantages of non-invasive, fast detection and visualization. In this paper, we reviewed the new progress of fluorescent probe targeted tumour recognition and introduced and analyzed the research progress of folate (FA) and folate receptor (FR) mediated fluorescence probe targeting. Folate receptor (FR) is a specific substance over expressed on the surface of cancer cells. Using the characteristic of specific binding between folate (FA) and folate receptor, folic acid can modify the fluorescent probe molecules to give the fluorescent probe the ability to recognize cancer cells. There are four subtypes of folate receptor (FR alpha, FR beta, FR gamma and FR delta). The former two FR alpha and FR beta are highly expressed on the surface of cancer cells and inflammatory macrophages, respectively. FR alpha and FR beta have about 70% homology. Both of them can bind to folate, which makes it difficult for fluorescent probes to distinguish cancer cells from inflammatory macrophages in the process of biological recognition. It is difficult to distinguish folate receptor subtypes by modified fluorescent probes, which leads to confusion between cancer cells and inflammatory macrophages. The chiral characteristics of the two folate receptor subtypes are analyzed : FR alpha and FR beta is mainly located in three untranslated regions. Three kinds of amino acids with different chiral characteristics form a triangular cavity to bind folate molecules. The three kinds of amino acids fixed on the nodes of amino acid accumulation form a regional "chiral space" with different chiral characteristics. The structures of FR alpha and FR beta are different for different ligands. Based on the "chiral space" differences of folate receptor subtypes, the possibility of constructing fluorescent and chiral recognition probes is discussed. It is expected that with the help of spectral imaging, the two folate receptor subtypes can be distinguished by the recognition of amino acids by chiral fluorescent probes, and the recognition problem of tumor cells and inflammatory macrophages can be realized to improve the recognition ability of cancer cells in this paper, the principle of amino acid recognition by chiral fluorescent probes and the progress of structural optimization design are introduced. In recent years, the research of chiral quantum dots on different enantiomers of amino acids has attracted much attention. This paper summarises the nature of chiral generation of inorganic chiral quantum dots and the recognition of amino acid enantiomers. Finally, the prospect of fluorescent probes and chiral recognition is discussed.