Synthesis Of Fluorescent Dyes For DNA Detection And Mitochondria Imaging

With the development of technology and urgent needs of biological research, fluorescence based optical microscopy is applied for the detection of ions or molecules, cell and tissue imaging etc. due to its advantages such as easily available equipments, simple operation and high sensitivity.DNA, one of the important macromolecules in the vital bodies, is the genetic carrier and controls the biological growth and operation. Meanwhile, the natural physiology is affected by the DNA changes. So detection of DNA in a direct and convenient way will contribute to the medical diagnosis. In order to realize the DNA quantification and live-cell imaging, the sensor DEAB-TO-1was synthesized based on the past work. As a specific DNA probe, DEAB-TO-1shows little fluorescence (Quantum Yield=7.35×10-4, H2O), but is so strongly fluorescent (Quantum Yield=0.33, H2O) upon rapidly binding to DNA in an embedding manner that the800-fold enhanced emission makes it seen by naked eyes. The probe can detect trace DNA with a detection limit of0.57ng/ml and quantitatively monitor DNA from3.28to4200ng/ml. Moreover, DEAB-TO-1is good membrane-permeable and its ability of live-cell nuclei imaging proves the value for practical application.Most cells contain substantial numbers of double-membrane mitochondria which are called "powerhouse" owing to their major function of providing energy in ATP manner by oxidative phosphorylation. However, mitochondria have many other roles including the modulation of intracellular calcium concentration and the regulation of apoptotic cell death. Furthermore, mitochondrial dysfunction leads to a number of diseases ranging from neurodegenerative diseases to obesity and tumor. Nowadays, dyes for mitochondria imaging are almost developed on the cyanine and rhodamine frameworks which are recognized as complexes of strengths and weaknesses respectively. To enrich the kind and realize near-infrared imaging, the compound MDTDBB based on BODIPY was explored for mitochondria. The results show that the absorption and emission of MDTDBB are all above650nm and the dye displays relatively bright fluorescence (Quantum Yield=0.305, CH3CN). Through the co-staining and membrane-potential experiments, the dye is proved to be mitochondria-targeted and suffers little from membrane-potential. Meanwhile, in this work, the red-shift of spectra by quaternarization of the pyridine at the middle position is explained utilizing the simulation of molecule orbits with the software Grauss09.