The Design And Synthesis Of New Near-infrared Fluorescent Probes For Regional Location And Detecting Functionality Cations In Cells

There are many different kinds of functional cations in living organism, they play an unique role in physiological and pathologic process. For example, irons participate in the storage and transportation of oxygen and metabolism in organism. In particular, ferrous iron (Fe²⁺), may facilitate the generation of highly reactive oxygen species, particularly the deleterious hydroxyl radical. Also, the lower activity of zinc could resulte in the injury of neuron and apoptosis; while the excess of zinc could lead to zinc poisoning. Therefore, the detection of cations in living cells has important medicine and biology significance. Fluorimetric method have been widely studied for the detection of functional cations, due to their unique advantages such as high sensitivity and selectivity, simple and quick, real-time detection of cations in situ. There are good prospects of developing cations fluorescent probes, in a variety of fields such as environmental chemistry, analytic chemistry and biomedicinal science.To design and synthesize high selectivity and high sensitivity fluorescence probe for detecting functional cations in live cells, we can learn more about the biological function of cations. Furthermore, the precisely mechanism of these cations in organism could be studied deeply.Based on the research status of functional cations fluorescence probe, we carried the following nvestigation:First, we designed and synthesized a new ratiometric fluorescent probe (BDP-Cy-Tpy) for determination Fe²⁺ concentration fluctuations in biological systems. The probe was prepared by linking a Fe²⁺-insensitive fluorophore (BODIPY) to a Fe²⁺-sensitive reporter-fluorophore fragment (Cy-Tpy). When Fe²⁺ bound to the receptor-Tpy, an efficient photo-induced electron transfer (PET) process happened from the Fe²⁺-Tpy complex to the Cy group of BDP-Cy-Tpy. As a result, the fluorescence intensity of Cy-Tpy fragment could be quenched instantaneously, while the fluorescence intensity of BODIPY fragment was basically unchanged. The ratio of fluorescence intensity showed a linear relationship toward the concentrations of Fe²⁺. The probe instantly responded to Fe²⁺ with high sensitivity and selectivity. Also, the probe was used to ratiometricly image the concentration fluctuations of intracellular and adscititious Fe²⁺ in living HL-7702 and HepG2 cells for the first time. The results also provided a new approach for potential biological and clinical implications.