Cationic Organochalcogen with Monomer/Excimer Emissions for Dual-Color Live Cell Imaging and Cell Damage Diagnosis

Abstract

Studies on the development of fluorescent organic molecules with different emission colors for imaging of organelles and their biomedical application are gaining lots of focus recently. Here, we report two cationic organochalcogens 1 and 2, both of which exhibit very weak green emission (Φ = 0.12%; Φ = 0.09%) in dilute solution as monomers, but remarkably enhanced green emission upon interaction with nucleic acids and large red-shifted emission in aggregate state by the formation of excimers at high concentration. More interestingly, the monomer emission and excimer-like emission can be used for dual color imaging of different organelles. Upon passively diffusing into cells, both probes selectively stain nucleoli with strong green emission upon 488 nm excitation, whereas upon 405 nm excitation, a completely different stain pattern by staining lysosomes (for 1) or mitochondria (for 2) with distinct red emission is observed because of the highly concentrated accumulation in these organelles. Studies on the mechanism of the accumulation in lysosomes (for 1) or mitochondria (for 2) found that the accumulations of the probes are dependent on the membrane permeabilization, which make the probes have great potential in diagnosing cell damage by sensing lysosomal or mitochondrial membrane permeabilization. The study is demonstrative, for the first time, of two cationic molecules for dual-color imaging nucleoli and lysosomes (1)/mitochondria (2) simultaneously in live cell based on monomer and excimer-like emission, respectively, and more importantly, for diagnosing cell damage.

Structural Modification Orientated Multifunctional AIE Fluorescence Probes: Organelles Imaging and Effective Photosensitizer for Photodynamic Therapy

“…Why are structurally similar compounds with different organelle staining? Referred to the literature reported before, it is essential to understand the structural character of the targets. For mitochondrion, it has a very large membrane potential up to −180 mV, which is more negative than that of other cellular components .…”

“…For mitochondrion, it has a very large membrane potential up to −180 mV, which is more negative than that of other cellular components . For lysosome, it is a spherical vesicle containing hydrolytic enzymes with an acid environment (pH = 4.7) . Many foreign substances need to be encapsulated in lysosomes to be utilized by cells, which is a way of cell self‐protection.…”

“…We could find there was no fluorescence in the cells after incubating HeLa cells with Cytochalasin D for TPE‐IQ‐TPA (Figure ), while the fluorescence nearly all aggregated in the cytomembrane without entering the cells for TPE‐IQ‐CN (Figure ), indicating that endocytosis is the transport mechanism for internalization of TPE‐IQ‐CN and TPE‐IQ‐TPA. According to the time‐dependent and temperature‐independent internalization process in HeLa, it is reasonable that TPE‐IQ‐CN and TPE‐IQ‐TPA pass through the cell membrane via endocytosis and localize in lysosomes . Namely, TPE‐IQ‐CN and TPE‐IQ‐TPA entered cells by endocytosis as foreign matters, which will get to the lysosome when entering cells .…”

Multifunctional N-P-doped carbon dots for regulation of apoptosis and autophagy in B16F10 melanoma cancer cells and in vitro imaging applications

“…Considering similar applications, presently, the fluorescence imaging of cells, biological tissues, and specific localized sub-cellular organelles (nuclei, mitochondria, and/or lysosomes) based on fluorescent molecules have attracted considerable attention across medical fields for an in-depth understanding of biological processes and pathways toward early disease diagnosis and drug development in biomedicine 9 - 11 . Besides, fluorescence imaging can visualize the expression and activity of specific molecules as well as cellular and biological processes that influence tumor behavior and response to therapeutic drugs 12 .…”

Chiral stacking of cyanine or porphyrin as cationic fluorescent dyes in the presence of anionic polysaccharide of hyaluronic acid

“…They are part of an important family of fluorophores, which have been widely used for photosensitization and optical recording materials [2,3,10]. Porphyrins are well known to form chiral aggregate in the presence of DNA and act as the stabilizer for the secondary structure of nucleic acid [11][12][13][14][15]. 5, 10, 15, 20-Tetrakis (1-methylpyridinium-4-yl) porphyrin p-toluene sulfonate (TMPyP) is one of the water soluble cationic porphyrins.…”