A Novel Fluorescent Probe For DNA Sensing And Bio-Imaging

Most of organisms are composed of different type cells,and these cells contain many biological molecules.Deciphering the molecular mechanisms inside and between cells in complex living systems is one of the ultimate goals of modern biological research.Since most biomolecules lack universal features that can distinguish them from other molecules by simple optical observation,scientists have to rely on special techniques to study their behavior.Due to the high sensitivity and simplicity of fluorescent probes and the rapid development of advanced instruments and operating technologies,fluorescent probes have become the most widely used tools for biosensing and bio-imaging.In this study,with perylene as the main structure,a new type of organic small molecule fluorescent probe------perylene derivatives(PDI)with aggregation-inducing properties is designed and synthesized.The probe molecules can aggregate under the induction of DNA and have a strong luminous efficiency,which can realize DNA sensing and biological imaging.And we have effectively optimized the bounding conditions,reduced the background fluorescence,and improved the sensitivity.The main research contents of this paper are as follows:1.The fluorescent probe PDI with perylene as the main structure was synthe-sized and used for DNA sensing.After the probe molecule PDI was added to DNA,the fluorescence changed from blue in the monomer state to green in the aggregate state,and a large spectral red shift appeared,which proved that PDI can aggregate under the induction of DNA to produce association fluorescence.We have confirmed this phenomenon through spectroscopy and gel electrophoresis,and proved that PDI can be used as a new stain for DNA detection.In addition,experiments have shown that the effect of this aggregation effect is affected by the concentration of PDI and DNA.The aggregation efficiency is directly proportional to the concentration of PDI.The higher the concentration of nucleotides,the stronger the efficiency,but when the concentration exceeds a certain threshold,the increase in concentration will result in a decrease in efficiency.We optimize the PDI-DNA binding system in six aspects: buffer type,DNA sequence and structure,p H,temperature,and salt ions.It is found that the buffer has the best effect when the p H is neutral or alkaline,and the aggrega-tion effect is shown as the base "T" > "A" > "G" > "C","double strand" > "single strand".At the same time,the lower the temperature,the lower the salt ion concen-tration,and the more obvious the aggregation of PDI induced by DNA.The probe is sensitive to DNA and has good light stability,and has important application pro-spects in the field of DNA sensing and detection.2.Explore the application of probe molecule PDI in biological imaging.The experimental results show that PDI can be evenly dispersed in the cytoplasm outside the nucleus,and the image is clear.It can be observed in two channels of green(Ex=488nm)and blue(Ex=405nm),at a very low concentration of 200 n M.It can realize the visualization of Hela cells,PK cells,Vero cells and embryos.The probe does not have any inhibitory effect on cell proliferation within the concentration range of 0-30 ?M,and has no obvious effect on the embryonic blastocyst develop-ment rate,and has low biological toxicity.In addition to good biocompatibility,PDI also has excellent optical stability and has potential applications in cell and embryo imaging.