A General Strategy For The Construction Of NIR Emitting Si-rhodamines And Visualization Of Mitochondrial Temperature

Si-rhodamine improves their resistance to photobleaching,while retaining the key advantages that rhodamines have many biological applications,such as water-solubility,p H independency of photophysical properties,and mitochondrial localization in cells.the synthesis of Si-rhodamine is generally through the reaction of aryllithium and Sixanthone,and functional modification requires complex protection strategies.Therefore,it is urgent to construct a new synthesis strategy for Si-rhodamine.Mitochondria are essential organelles and play roles in many important metabolic processes such as signaling,cellular differentiation and apoptosis,and storage of calcium ions.Mitochondria act as the power generators of the cell and their temperature variation may be a sign of the status of mitochondrial energetics.In some diseases,cellular dysfunctions,originating in disordered energy metabolism,might be revealed by abnormal changes of local temperature in mitochondria.As the developing of biology and medical science,detection of mitochondrial microenvironment in both healthy and unhealthy mitochondrial becomes a popular and essential subject.However,monitoring in real-time the local temperature within mitochondria is extremely challenging.The main research contents are as follows:1.A series of functional substituents(such as-NO2,-CH2 Cl,-N(CH3)2,-C≡CH,etc.)Si-rhodamine dyes are constructed through the reaction of diarylsilyl ether and arylaldehyde.These Si-rhodamines exhibit excellent light stability,high water solubility and near-infrared luminescence as well as temperature-dependent fluorescence changes.By adjusting the electronic effects of meso-substituents,a fluorescence-enhanced p H probe was designed.2.A mitochondrial-targeted Si-rhodamine probe,Si R 8,was synthesized and covalently immobilized on the mitochondria using "Click" reaction between benzyl chloride and protein thiol.Si R 8 shows reversible temperature dependence,good biocompatibility,high photostability and mitochonadrial targeting ability.Through mitochondrial temperature quantification,changes in mitochondrial temperature were dynamically detected.