| Mitochondria are energy factories of cells, which play vital roles in the processes of energymetabolism and apoptosis. As the major generation site of reactive oxygen species （ROS）,mitochondria are closely related to signal transduction and a variety of serious diseases includingcancer, diabetes, Alzheimer’s and other neurodegenerative disorders. Therefore, researches aboutROS and other active molecules in mitochondria have attracted great attention. Superoxide anionradical （O2-.） is precursor of total ROS, byproduct of electron transfer chain produced inmitochondria, and can be transformed to other ROS. This means that O2-.decided the levels ofother ROS. Recently, researches indicated that O2-.within mitochondria is closely related tomany vital diseases, including inflammation, aging and cancer. Therefore, To visualize O2-.insitu in mitochondria is of great importance.O2-.has low steady state concentration and short lifetime in mitochondria because it can betransformed to other ROS quickly. In addition, Compartments inside mitochondria are verycomplicated. Those reasons mentioned above make the detection of O2-.rather difficult. Reportsabout small molecular fluorescent probes for O2-.in cells and living organisms with highselectivity and sensitivity are still rare. However, two-photon fluorescent probes whoseexcitation wavelength in near infrared region have many advantages over one-photon fluorescentprobes. For example, little photodamage, increased penetration depth, decreased biologicalback ground of large molecules, high resolution, reduced photobleaching and so on. Amongtwo-photon fluorescent materials, derivatives of fluorene and carbazole own a number ofadvantages, including perfect rigid coplanar structure, large action cross section, largedelocalizability and are easy to be modified. These advantages are indicative of their wideapplication in two photon fluorescent probes.To overcome these limitations of detecting O2-.in mitochondria, it is crucial to design andsynthesize two photon fluorescent probes for O2-.with large action cross sections, goodbiocompatibility and high selectivity, which is currently one of Hot spots and pain points in lifescience studies. Accordingly, we carried out three aspects of investigation:Firstly, we designed and synthesized a new two photon fluorescent probe MF-DBZ todetect O2-.in mitochondria. This probe consists of three moieties: a two photon fluorophorefluorene, a O2-.responsive group benzothiazoline, and a location group triphenylphosphine.Synthesis of this probe was comparably simple. Investigations on synthesis path were carried out.Structure of probe was characterized by NMR, IR and MS.Secondly, two photon fluorescent probe MF-DBZ were applied to detect O2-.in chemical and biological system. fluorescence Spectra showed that this probe possessed potent selectivityto O2-.and could respond to fluctuation of O2-.concentrations quickly. In addition, laser confocalmicroimaging experiments indicated that this probe could respond to O2-.in mitochondria ofliving cells with high selectivity.Thirdly, we designed and synthesized a new two photon fluorescent probe MitoCA to detectO2-.in mitochondria. This probe consists of three moieties, a two photon fluorophore carbazole,O2-.responsive group benzothiazolinone, and location group triphenylphosphine. It wascharacterized by NMR, IR and MS. Fluorescence of probe was very weak, a dramatic increase influorescence was observed when reacting with O2-.. Studies on spetra properties of this probeindicated that this probe has high selectivity and sensitivity. |
PDF Full Text Request