The Synthesis And Application Of Organelle-Targetable Fluorescent Probes Based On Naphthalimide

With continuously deepening exploration in life sciences, the fluorescent imaging and detecting of living cells extended into more microscopic structures. As a result, organell etargetable fluorescent probes emerged and have developed rapidly in recent years. While naphthalimide chromophores have been widely developed into probes because of its good fluorescence quantum yield, light stability and two-photon properties, the organelle-targetable naphthalimide probes with identification functions have been scarcely developed. In this paper, we designed two organelle targetable fluorescent probes based on naphthalimide, which are used for tracing mitochondrial membrane potential and detecting NO around the cell membrane.In this paper, we designed and synthesized a bipolar fluorescent probe named MITFPS, which is based on naphthalimide and could stably target to mitochondria. Spectrum test showed that MITFPS has two-photon activities and its fluorescence intensity is sensitive to the polarity of the solvent. Fluorescence lifetime test proved that the fluorescence lifetime of MITFPS is shortened while the solvent polarity is enhanced. The co-localization and cell fixation experiments demonstrated that MITFPS can stably target to mitochondrias. Fluorescence imaging showed that significant morphological’changes occur on the mitochondrias of MCF-7 cells after stimulated by dexamethasone. In addition, MITFPS is capable to indicate the changes of pathologic mitochondrial membrane potential through two-photon fluorescence lifetime imaging.A fluorescent probe named MEM-STNO, was synthesized for the first time in this paper. It is a cell membrane-targetable probe for detecting nitric oxide around the cell membrane. MEM-STNO has an amphipathic structure, which is based on naphthalimide and takes the classic NO acceptor o-diaminobenzene as the receptor unit. Nitric oxide response experiment proved that MEM-STNO is highly sensitive to nitric oxide. The response increased its fluorescence intensity for nearly 21 times.The confocal fluorescent imaging of MCF-7 and nerve cells suggested that MEM-STNO can target on different kinds of cell membranes and stain for as long as 60 min. Exogenous nitric oxide to stimulate cell experiment demonstrated that MEM-STNO can quickly detect the nitric oxide around cell membranes and get fluorescence enhanced signals.