Design And Optical Imaging Applications Of Molecular Fluorescence Probes For Polarity And Viscosity In Organisms

The state of the microenvironment in organisms is closely related to the health of the organism itself.When disease cells invade,they actively interact with the microenvironment through the extracellular matrix or through the vascular endothelium through biomechanical or biochemical signals,thus changing some parameters of the microenvironment,such as the polarity and viscosity of the microenvironment.Therefore,monitoring the parameters of the microenvironment is an important means to detect the health of organisms.Fluorescence probe imaging technology has become an important means of detect microenvironment parameters with high sensitivity,excellent selectivity and simple operation.In this paper,three kinds of fluorescent probes were constructed based on different optical effects,and their optical properties and applications were studied as follows:(1)Based on intramolecular charge transfer effect(ICT),near-infrared emission fluorescent probe SSR-LDs was used to detect the polarity changes in intracellular lipid droplets.The probe has super-sensitive polarity sensitivity,excellent chemical stability and light stability,and can distinguish normal cells from cancer cells by comparing the microenvironment in cells through cell imaging experiments.At the same time,the probe can sensitively monitor the change of lipid drop polarity in living cells.More importantly,using the constructed fluorescent probe,SSR-LDs has achieved in vitro fluorescence detection of liver injury and fatty liver,as well as in vivo hepatitis detection.(2)Using oxanthracene as luminescent groups and electron donors,and benzothiazole with cationic and ethyl acetate groups as electron receptors,a near infrared fluorescent probe SSR-Mito,which can target mitochondria and detect their viscosity,is designed to monitor the health status of organisms in vivo according to the viscosity in mitochondria.Because the probe has long emission wavelength,good tissue penetration,little light damage to biological samples,and low spontaneous fluorescence,it complements the photoacoustic imaging experiment,avoids the scattering effect of biological tissues,and can obtain high resolution(100 μM)and deeper tissues.(3)Based on the fluorescence transfer mechanism of TICT,a fluorescence energy acceptor was used with the strong electron pulling property of quinoline quaternary ammonium salt,and a nitro group was introduced into the amino group in order to reduce the fluorescence emission intensity of the probe under the condition of low viscosity.Therefore,the fluorescence probe QUI-VI capable of detecting intracellular viscosity was reasonably constructed.Probe QUI-VI not only has high sensitivity to viscosity,high selectivity,excellent p H adaptability,light stability and good biocompatibility.At the same time,the probe has a large Stokes shift,so the probe promising to be used in vivo imaging and for early clinical pneumonia diagnosis research.