De Novo-Designed Near-Infrared Nanoaggregates for Super-Resolution Monitoring of Lysosomes in Cells, in Whole Organoids, and in Vivo

Abstract

As the cleaners of cells, lysosomes play an important role in circulating organic matter within cells, recovering damaged organelles, and removing waste via endocytosis. Because lysosome dysfunction is associated with various diseaseslysosomal storage diseases, inherited diseases, rheumatoid arthritis, and even shockit is vital to monitor the movement of lysosomes in cells and in vivo. To that purpose, a method of optical imaging, super-resolution imaging technology (e.g., SIM and STORM), can overcome the limitations of traditional optical imaging and afford a range of possibilities for fluorescence imaging. However, the short wavelength excitation and easy photobleaching of super-resolution fluorescence probes somewhat problematize super-resolution imaging. As described herein, we designed a low-toxicity, photostable, near-infrared small molecule fluorescence probe HD-Br for use in the super-resolution imaging of lysosomes. The interaction of lysosomes and mitochondria was dynamically traced while using the probe’s properties to label the lysosomes. Because the probe has the optimal near-infrared excitation and emission wavelengths, liver organoid 3D imaging and Caenorhabditis elegans imaging were also performed. Altogether, our findings indicate valuable approaches and techniques for super-resolution 3D and in vivo imaging.

Fluorescent Probes for Super-Resolution Microscopy of Lysosomes

“…In this work, 4-bromoresorcinol was treated with the commercially available heptamethine dye IR-780 under appropriate conditions, yielding the hemicyanine product, HD-Br. 21 Based on passive targeting of lysosome via the endocytosis mechanism, the dye formed a nanoaggregate in the aqueous solution that could specifically target the lysosomes. Using this probe, a SIM-based imaging of mitochondria–lysosome contact (MLC) and mitochondria–lysosome interactions in mitophagy was performed.…”

A dual-labeling probe to track functional mitochondria–lysosome interactions in live cells

“…Due to the limitation of Abbe's diffraction limit (<200 nm) 7 , this event cannot be captured under epi-illumination fluorescence microscopy or confocal microscopy 8 . To date, such MLC events have only been defined by the physical distance observed by superresolution microscopy 9 and electron microscopy 2 . However, precise MLC sites cannot be directly visualized using current biochemical and cellular approaches.…”

An Activatable and Switchable Nanoaggregate Probe for Detecting H2S and Its Application in Mice Brains

“…This phenomenon reflected a typical formation of Htype aggregation. [46,47] As for the fluorescence spectra, a certain aggregation-induced quenching phenomenon was also observed, which further indicated that the increase of water content would cause the aggregation ( Figure S19b). Next, in order to ensure whether the aggregation of HSDP formed nanoparticles in aqueous solution, dynamic light scattering (DLS) and transmission electron microscope (TEM) experiments were performed.…”