| Fluorescence imaging is a technology that can directly obtain real-time structural state images of cell tissues,organs,living organisms,etc by applying fluorescent probes as media and optical microscopes as detectors,which has attracted the attention in the fields of analytical chemistry,medical imaging,and disease treatment.due to their superior advantages of non-invasiveness,high station-temporal resolution,simplicity,sensitivity and real-time dynamic monitoring.The effect of fluorescence imaging and the accuracy of the analytical results is highly relied on the properties of fluorescent probes,such as toxicity,optical properties,specificity and sensitivity.Therefore,as the most key step in fluorescence imaging technology,the preparation of high-quality,low-toxicity probes is of great significance.In this paper,two fluorescent probes with low toxicity and excellent optical properties were prepared by different methods,and their imaging capabilities were investigated.The first chapter is Introduction.The fluorescent method was reviewed firstly,and the recognition mechanism and possible toxic source of fluorescent probes ad the common detect methods for the determination of toxicity were briefly introduced.Then several types of representative fluorescent probes that have been developed so far,the preparation methods,luminescence mechanism and biological imaging applications of organic small molecule fluorescent probes and carbon dot fluorescent probes.Three representative applications of fluorescent probes in imaging analysis are sorted out,including in vitro imaging,tracking and positioning imaging,and drug therapy.Finally,the research purpose and main content of this thesis are explained.In Chapter 2,1,2,4-Triaminobenzene as a fluorescent probe for intracellular p H imaging and point-of-care ammonia sensing.We discovered that the commercially available 1,2,4-triaminobenzene hydrochloride which was purified by simple treatment and then dispersed in ultrapure water could be employed as fluorescent probe.The probe is low-cost and the preparation is quite easy has lots of advantages like low toxicity,good photostability,and p H-sensitive UV-fluorescence dual-mode response capability.In order to show the applicability of the proposed probe,it was employed to image various organelles related with diseased cells and cancer cells that showed abnormal p H.More importantly,it was also applied for stain diabetic mouse tissue sections,which showed the great potential in practice applications.Additionally,benefiting from the excellent feature like p H-sensitive fluorescence-UV dual-mode and recyclable of the probe,we further fabricated a portable and repeatable test strips which could be applied for visual semi-quantitative determination of ammonia in the form of gas by naked eye or under the irradiation of 365 nm UV lamp directly.In Chapter 3,the preparation of multicolor carbon dots and their application in fluorescence imaging.A series of carbon dots with different fluorescence emission were prepared under the same optimum conditions,such as the carbon precursor,reaction temperature and time in ethanol/water mixed solvents with different volume ratios.Based on the controllable and comparable characteristics of the reaction system,the fluorescence emission mechanism of its carbon dots were explored,the results showed that the quantum confinement effect and the sp~2 conjugate structure caused by the saturated vapor pressure of its system were the main reasons for the emission.Based on the above method,another series of multicolor carbon dots in the mixed isopropanol/water solvent of water were prepared,which confirmed the mechanism and the feasibility and universality of the strategy.At the same time,as the excellent optical properties,high quantum yield and low toxicity of the synthesized carbon dots,they were used for fluorescence imaging within Hela cells which verified the great potential of the method for simultaneous imaging analysis and detection of multiple targets. |
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