Deep-Red-Fluorescent Zinc Probe with a Membrane-Targeting Cholesterol Unit.

Organelle-targeting fluorescence probes are valuable because they can provide spatiotemporal information about the trafficking of analytes of interest. The spatiotemporal resolution can be improved by using low-energy emission signals because they are barely contaminated by autofluorescence noises. In this study, we designed and synthesized a deep-red-fluorescent zinc probe (JJ) with a membrane-targeting cholesterol unit. This zinc probe consists of a boron-azadipyrromethene (aza-BODIPY) fluorophore and a zinc receptor that is tethered to a tri(ethylene glycol)-cholesterol chain. In aqueous solutions buffered to pH 7.4, JJ exhibits weak fluorescence with a peak wavelength of 663 nm upon excitation at 622 nm. The addition of ZnCl2 elicits an approximately 5-fold enhancement of the fluorescence emission with a fluorescence dynamic range of 141000. Our electrochemical and picosecond transient photoluminescence investigations indicate that the fluorescence turn-on response is due to the zinc-induced abrogation of the formation of a nonemissive intramolecularly charge-separated species, which occurs with a driving force of 0.98 eV. The fluorescence zinc response was found to be fully reversible and to be unaffected by pH changes or the presence of biological metal ions. These properties are due to tight zinc binding with a dissociation constant of 4 pM. JJ was found to be nontoxic to HeLa cells up to submicromolar concentrations, which enables cellular imaging. Colocalization experiments were performed with organelle-specific stains and revealed that JJ is rapidly internalized into intracellular organelles, including lysosomes and endoplasmic reticula. Unexpectedly, probe internalization was found to permeabilize the cell membrane, which facilitates the influx of exogens such as zinc ions. Such permeabilization does not arise for a control probe without the tri(ethylene glycol)-cholesterol chain (JJC). Our results show that the membrane-targeting cholesterol unit can disrupt membrane integrity.

Monocycloplatinated Solvento Complex Displays Turn-on Ratiometric Phosphorescence Responses to Histamine.

The study of biological histamine (HA) requires probes capable of ratiometric photoluminescence detection of HA. We discovered that a monocycloplatinated complex having two solvento ligands ([Pt(2-(2-naphthyl)quinolinate)(NCCH3)2]ClO4) could produce ratiometric phosphorescence responses to HA in aerated aqueous solutions buffered to pH 7.4. The HA response was characterized with a hypsochromic shift of an emission peak wavelength from 635 to 567 nm. The corresponding phosphorescence intensity ratio (i.e., I567 nm/ I635 nm) increased from 0.26 to 1.90. Spectroscopic and spectrometric investigations indicated an occurrence of spontaneous displacement of the labile CH3CN ligands with HA. An independently prepared HA adduct supported this notion. The ratiometric phosphorescence responses to HA were highly tolerant to other biological stimuli, including changes in pH and the presence of biometals and biological Lewis bases such as amino acids, nucleosides, biothiols, neurotransmitters, and small molecular metabolites. Of note was the high selectivity toward HA over common biological ligands, including histidine, cysteine, and homocysteine, which was ascribed to tighter HA binding. Our phosphorescence measurements employing Boc-protected derivatives of HA suggested that the bis-chelate motif involving imidazolyl and terminal amino groups was crucial for eliciting the ratiometric phosphorescence signaling. Finally, the bioimaging utility of the HA probe was validated using RAW 264.7 macrophages that were exogenously supplemented with HA or stimulated with thapsigargin to enrich intracellular HA. Ratiometric phosphorescence imaging microscopy experiments demonstrated the ability of the probe for monitoring intracellular HA uptake. In addition, photoluminescence lifetime imaging microscopy techniques could be applied for visualization of HA within the RAW 264.7 cells, because the HA binding elongated the photoluminescence lifetime. Our study demonstrated the promising utility of inner-sphere interactions of phosphorescent Pt(II) complexes for detection of biological HA.

Recurrent skin opening induced by chronic sternal osteomyelitis caused by a bite wound in a cat: A case report.

BACKGROUND: Chronic sternal osteomyelitis is a rare condition in felines, with limited reported cases to date. OBJECTIVES: We report the case of a 2-year-old castrated male, domestic shorthair cat, weighing 4.68 kg, that presented with skin openings every 3-4 months, despite skin debridement and reconstruction. METHODS: A subcutaneous dead space larger than the skin defect was detected. Haematological analysis revealed elevated levels of inflammatory markers. Thoracic radiography revealed sternal deformation and suspected osteomyelitis. Computed tomography revealed a fistula extending from the third to the fourth sternebrae. RESULTS: Bone and soft tissue debridement and abscess flushing were performed along with long-term antibiotic therapy. The cat remained recurrence-free throughout an 18-month post-surgery follow-up period. CONCLUSION: To the best of our knowledge, this is the first report of chronic osteomyelitis occurring in a cat's sternebrae and represents the first successful case of its treatment. This case showcases the potential for improved treatment outcomes in similar cases. Understanding and successful treatment of such cases can pave the way for better management of feline osteomyelitis.

Imaging guided adrenalectomy with Indocyanine green fluorescence in a dog with a pheochromocytoma.

IMPORTANCE: This case report presents the successful surgical removal of a pheochromocytoma in a dog using indocyanine green (ICG) fluorescence imaging. CASE PRESENTATION: A 10-year-old, 6.87 kg, spayed female poodle was referred for an abdominal mass and eight episodes of vomiting. Computed tomography revealed masses in the spleen and left adrenal gland. Based on the plasma normetanephrine levels, the patient was diagnosed with pheochromocytoma. Subsequently, a total splenectomy and left adrenalectomy were performed. A dose of 5 mg/kg ICG was administered intravenously 24 h prior to surgery. Using ICG allowed visualization of tumor margins, aiding in complete resection and minimizing anesthesia-related risks. CONCLUSIONS AND RELEVANCE: No evidence of recurrence or metastasis has been observed for 12 months. To our knowledge, this is the first report of the surgical removal of a pheochromocytoma using intraoperative ICG imaging in veterinary medicine. This case highlights the efficacy of ICG fluorescence imaging as a valuable tool for the surgical management of adrenal tumors in veterinary medicine.

Efficient Ionovoltaic Energy Harvesting via Water-Induced p-n Junction in Reduced Graphene Oxide.

Water motion-induced energy harvesting has emerged as a prominent means of facilitating renewable electricity from the interaction between nanostructured materials and water over the past decade. Despite the growing interest, comprehension of the intricate solid-liquid interfacial phenomena related to solid state physics remains elusive and serves as a hindrance to enhancing energy harvesting efficiency up to the practical level. Herein, the study introduces the energy harvester by utilizing inversion on the majority charge carrier in graphene materials upon interaction with water molecules. Specifically, various metal electrode configurations are employed on reduced graphene oxide (rGO) to unravel its distinctive charge carriers that experience the inversion in semiconductor type upon water contact, and exploit this characteristic to leverage the efficacy of generated electricity. Through the strategic arrangement of the metal electrodes on rGO membrane, the open-circuit voltage (Voc) and short-circuit current (Isc) have exhibited a remarkable augmentation, reaching 1.05 V and 31.6 µA, respectively. The demonstration of effectively tailoring carrier dynamics via electrode configuration expands the practicality by achieving high power density and elucidating how the water-induced carrier density modulation occurs in 2D nanomaterials.

Lateral Electronic Junction of a Single Ultrathin Silicon Induced by Interfacial Dipole of Self-Assembled Monolayer.

Interface engineering is pivotal for enhancing the performance and stability of devices with layered structures, including solar cells, electronic devices, and electrochemical systems. Incorporating the interfacial dipole between the bulk layers effectively modulates the energy level difference at the interface and does not significantly influence adjacent layers overall. However, interfaces can drastically affect adjoining layers in ultrathin devices, which are essential for next-generation electronics with high integrity, excellent performance, and low power consumption. In particular, the interfacial effect is pronounced in ultrathin semiconductors, which have a weak electric field screening effect. Herein, the substantial interfacial impact on the ultrathin silicon is shown, the p- to n-type inversion of the semiconductor solely through the deposition of a self-assembled monolayer (SAM) without external bias. The effects of SAMs with different interfacial dipoles are investigated by using Hall measurement and surface analytic techniques, such as UPS, XPS, and KPFM. Furthermore, the lateral electronic junction of the ultrathin silicon is engineered by the regioselective deposition of SAMs with opposite dipoles, and the device exhibits rectification behavior. When the interfacial dipole of SAM is manipulated, the rectification ratio changes sensitively, and thus the fabricated diode shows potential to be developed as a sensing platform.