Highly Selective and Sensitive Two-Photon Fluorescence Probe for Endogenous Peroxynitrite Detection and Its Applications in Living Cells and Tissues

A new two-photon fluorescence probe for endogenous peroxynitrite (ONOO^–) detection was designed and synthesized. The probe exhibits good selectivity and sensitivity for ONOO^– in phosphate-buffered saline solution with a low detection limit (3.5 × 10^–8 M). Furthermore, the probe displays good performance in detecting endogenous ONOO^–, not only in RAW 264.7 cells but also in rat hippocampal tissue, with a high two-photon cross-section value (δ ≈ 100 GM) at a deep depth of 120 μm

Aggregation-Induced Fluorescence Probe for Monitoring Membrane Potential Changes in Mitochondria

Fluorescent probe <b>2</b> was designed for selectively determining mitochondria membrane potential changes. The probe selectively detects changes in the mitochondria membrane potential in a manner that is more sensitive than that of the commercially available indicator, Rodamine 123. As a result, the probe <b>2</b> is ideal for future studies designed to assess the functions of mitochondria in cells

Mitochondria-Targeted Reaction-Based Fluorescent Probe for Hydrogen Sulfide

In this study, we developed a turn-on mitochondria-targeting hydrogen sulfide, “<b>probe</b> <b>1</b>”, based on the selective thiolysis of 7-nitro-1,2,3-benzoxadiazole amine moiety attached to the piperazine-based naphthalimide scaffold. <b>Probe</b> <b>1</b> exhibited excellent properties with 68-fold fluorescence enhancement, a low detection limit (2.46 μM), a low cytotoxicity, and a good selectivity toward hydrogen sulfide. The success of intracellular imaging indicated that <b>probe</b> <b>1</b> could be used in further applications for the investigation of biological functions and pathological roles of H₂S in living systems

One-Photon and Two-Photon Sensing of Biothiols Using a Bis-Pyrene-Cu(II) Ensemble and Its Application To Image GSH in the Cells and Tissues

Glutathione (GSH), cysteine (Cys), and homocysteine (Hcy) are three major biothiols, which play key roles in various biological systems. Accordingly, the development of imaging probes has been actively studied. We report a new pyrene derivative <b>1</b>, which showed large fluorescence quenching with Cu²⁺ at pH 7.4. The ensemble <b>1</b>-Cu²⁺ was applied to detect biothiols. Among the various amino acids, GSH, Cys, and Hcy induced distinct turn-on fluorescence changes. The <b>1</b>-Cu²⁺ ensemble was further applied for GSH detection in living cells

Correction to “Cyanine-Based Fluorescent Probe for Highly Selective Detection of Glutathione in Cell Cultures and Live Mouse Tissues”

Correction to “Cyanine-Based Fluorescent Probe for Highly Selective Detection of Glutathione in Cell Cultures and Live Mouse Tissues

Nanostructured Phthalocyanine Assemblies with Protein-Driven Switchable Photoactivities for Biophotonic Imaging and Therapy

Switchable phototheranostic nanomaterials are of particular interest for specific biosensing, high-quality imaging, and targeted therapy in the field of precision nanomedicine. Here, we develop a “one-for-all” nanomaterial that self-assembles from flexible and versatile phthalocyanine building blocks. The nanostructured phthalocyanine assemblies (NanoPcTBs) display intrinsically unique photothermal and photoacoustic properties. Fluorescence and reactive oxygen species generation can be triggered depending on a targeted, protein-induced, partial disassembly mechanism, which creates opportunities for low-background fluorescence imaging and activatable photodynamic therapy. <i>In vitro</i> evaluations indicate that NanoPcTB has a high selectivity for biotin receptor-positive cancer cells (e.g., A549) compared to biotin receptor-negative cells (e.g., WI38-VA13) and permits a combined photodynamic and photothermal therapeutic effect. Following systemic administration, the NanoPcTBs accumulate in A549 tumors of xenograft-bearing mice, and laser irradiation clearly induces the inhibition of tumor growth

A Selective Imidazoline-2-thione-Bearing Two-Photon Fluorescent Probe for Hypochlorous Acid in Mitochondria

Hypochlorite (OCl^–) plays a key role in the immune system and is involved in various diseases. Accordingly, direct detection of endogenous OCl^– at the subcellular level is important for understanding inflammation and cellular apoptosis. In the current study, a two-photon fluorescent off/on probe (<b>PNIS)</b> bearing imidazoline-2-thione as an OCl^– recognition unit and triphenylphosphine (TPP) as a mitochondrial-targeting group was synthesized and examined for its ability to image mitochondrial OCl^– in situ. This probe, based on the specific reaction between imidazoline-2-thione and OCl^–, displayed a selective fluorescent off/on response to OCl^– with the various reactive oxygen species in a physiological medium. <b>PNIS</b> was successfully applied to image of endogenously produced mitochondrial OCl^– in live RAW 264.7 cells via two-photon microscopy