Biocompatibility of fluorinated poly(organophosphazene)

Fluorescent Solvatochromic Probes for Long-Term Imaging of Lipid Order in Living Cells

High-resolution spatio-temporal monitoring of the cell membrane lipid order provides visual insights into the complex and sophisticated systems that control cellular physiological functions. Solvatochromic fluorescent probes are highly promising noninvasive visualization tools for identifying the ordering of the microenvironment of plasma membrane microdomains. However, conventional probes, although capable of structural analysis, lack the necessary long-term photostability required for live imaging at the cellular level. Here, an ultra-high-light-resistant solvatochromic fluorescence probe, 2-N,N-diethylamino-7-(4-methoxycarbonylphenyl)-9,9-dimethylfluorene (FπCM) is reported, which enables live lipid order imaging of cell division. This probe and its derivatives exhibit sufficient fluorescence wavelengths, brightness, polarity responsiveness, low phototoxicity, and remarkable photostability under physiological conditions compared to conventional solvatochromic probes. Therefore, these probes have the potential to overcome the limitations of fluorescence microscopy, particularly those associated with photobleaching. FπCM probes can serve as valuable tools for elucidating mechanisms of cellular processes at the bio-membrane level.

[Synthesis of cationic manganese porphyrin bearing alkylsulfonio groups and evaluation of their antioxidant activities]

A water-soluble cationic 5, 10, 15, 20-tetrakis(2-dimethylsulfoniophenyl)-porphinatomanganese(III) ion (MnT2M(2)SuP) and a 5, 10, 15, 20-tetrakis(4-dimethylsulfoniophenyl)porphinatomanganese(III) ion (MnT4M(2)SuP) were synthesized as superoxide dismutase (SOD) mimics which were introduced into PEG-liposome composed of dimyristoylphosphatidylcholine (DMPC) and Pluronic F-68 to examine the effect of the liposome on the capacity for use as drug delivery system (DDS) to maintain and perpetuate blood circulation. Fluorescence spectra in pseudo blood circulation experiments indicated that MnT4M(2)SuP continued to be bundled in PEG-liposome, while fluorescence from cross-section of cell observed by confocal laser scanning microscope indicated that PEG-liposome was ingested into a cell. SOD activity was determined by stopped-flow analysis, which allowed the determination of k(cat) values for the reaction of the metalloporphyrins with superoxide anion radical (.O(2)(-)). Solution of PEG-liposome loaded with MnT2M(2)SuP or MnT4M(2)SuP were the most effective catalyst as a SOD mimic to decompose .O(2)(-) at second-order rate constants of 3.5-4.5 x 10(7) M(-1)s(-1).