Red Emissive Two-Photon Probe for Real-Time Imaging of Mitochondria Trafficking

Mitochondria trafficking plays an essential role for supplying energy in the neuronal system. We report here a red emissive two-photon probe for mitochondria (CMT-red) that showed high selectivity and robust staining ability for mitochondria, high photostability under a two-photon microscopy imaging condition, and low cytotoxicity. This probe can be easily loaded into live cells and tissue and used for real-time, high resolution imaging of the mitochondria trafficking in primary cortical neurons as well as in rat hippocampal tissue

Ratiometric Two-Photon Fluorescent Probe for Quantitative Detection of β‑Galactosidase Activity in Senescent Cells

We reported a ratiometric two-photon fluorescent probe (SG1) for β-galactosidase (β-gal) and its application to quantitative detection of β-gal activity during cellular senescence in live cells and in aged tissues. This probe is characterized by a significant two-photon excited fluorescence, a marked blue-to-yellow emission color change in response to β-gal, easy loading, insensitivity to pH and reactive oxygen species (ROS), high photostability, and low cytotoxicity. In addition, we show that SG1 labeling is an effective tool for quantitative detection of senescence-associated β-gal activity at the subcellular level in situ. This finding demonstrates that SG1 will find useful applications in biomedical research, including studies of cell aging

Two-Photon Dye Cocktail for Dual-Color 3D Imaging of Pancreatic Beta and Alpha Cells in Live Islets

Insulin-secreting beta cells together with glucagon-producing alpha cells play an essential role in maintaining the optimal blood glucose level in the body, so the development of selective probes for imaging of these cell types in live islets is highly desired. Herein we report the development of a 2-glucosamine-based two-photon fluorescent probe, <b>TP-β</b>, that is suitable for imaging of beta cells in live pancreatic islets from mice. Flow cytometry studies confirmed that <b>TP-β</b> is suitable for isolation of primary beta cells. Moreover, two-photon imaging of <b>TP-β</b>-stained pancreatic islets showed brightly stained beta cells in live islets. Insulin enzyme-linked immunosorbent assays revealed that <b>TP-β</b> has no effect on glucose-stimulated insulin secretion from the stained islet. Finally, to develop a more convenient islet imaging application, we combined our recently published alpha-cell-selective probe <b>TP-α</b> with <b>TP-β</b> to make a “TP islet cocktail”. This unique dye cocktail enabled single excitation (820 nm) and simultaneous dual-color imaging of alpha cells (green) and beta cells (red) in live pancreatic islets. This robust TP islet cocktail may serve as a valuable tool for basic diabetic studies