Mega-stokes pyrene ceramide conjugates for STED imaging of lipid droplets in live cells

Abstract

Lipid droplets are dynamic subcellular organelles that participate in a range of physiological processes including metabolism, regulation and lipid storage.

Facilely prepared aggregation-induced emission (AIE) nanocrystals with deep-red emission for super-resolution imaging

“…This is quite favorable to avoid autofluorescence interference and can also reduce the re-excitation process by STED beam. [12,37] Then, UV-vis absorption and PL spectra of DTPA-BT-H, DTPA-BT-MO and DTPA-BT-F in solvents with varied polarities were studied (Figure S11, Supporting Information), and the corresponding Lippert-Mataga plots were also obtained (Figure S12, Supporting Information). As we anticipated, red-shifted emission can be found in all the molecules when increasing the solvent polarity from hexane to dimethyl sulfoxide (DMSO), especially in the case of DTPA-BT-F, further suggesting its strong TICT effect in polar media.…”

“…This is quite favorable for avoiding auto-fluorescence interference and can also reduce the re-excitation process by the STED beam. 12,37 Then, UV-vis absorption and PL spectra of DTPA-BT-H, DTPA-BT-MO and DTPA-BT-F in solvents with varied polarities were studied (Fig. S11, ESI†), and the corresponding Lippert–Mataga plots were also obtained (Fig.…”

STED Nanoscopy Imaging of Cellular Lipid Droplets Employing a Superior Organic Fluorescent Probe

“…The fwhm resolution of the STED image is up to 65 ± 7 nm, which is substantially higher than the confocal image of 250 ± 6 nm (Figure c,d) and belongs to one of the leading results of LDs imaging (Table S1). − Notably, this high-resolution STED image is obtained under a relative weak STED laser intensity (16 MW cm –2 ), which is highly desired for live cell imaging with decreased photodamage. Further enhancing the fwhm resolution better than 65 nm may be realized by STED imaging with time-gated detection.…”

“…In the case of the STED nanoscopy imaging technique, it has two intrinsic requirements for fluorescent probes: (1) the probe should be able to be efficiently depleted by a STED laser; and (2) the probe should display very high photostability because of the tremendous energy of STED laser. , Since the traditional organic fluorescent probes could not satisfy these harsh demands, great efforts have been donated to develop new organic fluorescent probes capable for STED nanoscopy imaging. As a result, a few superior fluorescent probes have been reported very recently for STED nanoscopy imaging of various cellular organelles, e.g., LDs, − mitochondrial membrane, − cytoskeleton, , and so on. − Besides these organic molecular fluorescent probes, some organic/inorganic nanoparticles-based fluorescent probes have also emerged as powerful tools for STED imaging. − These works highlight the advantage of STED nanoscopy imaging over the traditional confocal/two-photon imaging, and significantly promote the relative study of cell biological on the nanoscale. However, fluorescent probes that are competent for STED nanoscopy imaging are quite limited.…”

Fluorescent Probes for STED Optical Nanoscopy

“…In Figure 4 , Lipi-DSB remains in a bright fluorescent state, while mitochondria stained with TMRM (Tetramethyl rhodamine methyl ester) are bleached out after 20 frames of STED illumination. O’Connor et al also developed a pyrene-based ceramide conjugate PyLa-C17Cer probe with a large Stokes shift and stains LD (Lipid Droplet) [ 95 ]. Thanks to its high target specificity, low cytotoxicity, and high photostability compared to PyLa, PyLa-C17Cer is more suitable for live cell imaging.…”