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A through-bond energy transfer-based ratiometric fluorescent pH probe: For extreme acidity and extreme alkaline detection with large emission shifts
摘要： A ratiometric fluorescence pH probe 1 based on through-bond energy transfer (TBET) with a 2-(2-hydroxyphenyl)benzoxazole (HBO) as donor and a Rhodamine derivative as acceptor is developed through simple condensation reaction. The probe exhibits a ratiometric fluorescence emission (I593/I422) characteristics and linear response to extreme acidity range of 5.00-2.88, and a ratiometric fluorescence emission (I555/I422) characteristics and linear response to extreme alkaline range of 10.00-13.78, respectively. Moreover, 1 possesses highly selective response to pH over metal ions, good reversibility and excellent photostability. Probe 1 is cellpermeable and can distinguish near pH 5.55 fluctuations in Hela cells. Furthermore, 1 can be immobilized on a test paper, which shows a rapid and reversible colorimetric response to HCl/NH3 vapor by the naked-eye.
关键词： ratiometric fluorescent response,pH sensing,large emission shifts,through-bond energy transfer,fluorescent probe
更新于2025-11-21 11:24:58
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Fluorescent membrane markers elucidate the association of Borrelia burgdorferi with tick cell lines
摘要： This study aimed to describe the association of Borrelia burgdorferi s.s. with ixodid tick cell lines by flow cytometry and fluorescence and confocal microscopy. Spirochetes were stained with a fluorescent membrane marker (PKH67 or PKH26), inoculated into 8 different tick cell lines and incubated at 30°C for 24 h. PKH efficiently stained B. burgdorferi without affecting bacterial viability or motility. Among the tick cell lines tested, the Rhipicephalus appendiculatus cell line RA243 achieved the highest percentage of association/internalization, with both high (90%) and low (10%) concentrations of BSK-H medium in tick cell culture medium. Treatment with cytochalasin D dramatically reduced the average percentage of cells with internalized spirochetes, which passed through a dramatic morphological change during their internalization by the host cell as observed in time-lapse photography. Almost all of the fluorescent bacteria were seen to be inside the tick cells. PKH labeling of borreliae proved to be a reliable and valuable tool to analyze the association of spirochetes with host cells by flow cytometry, confocal and fluorescence microscopy.
关键词： Fluorescent membrane marker,Tick cell lines,Borrelia burgdorferi,Phagocytosis
更新于2025-11-21 11:24:58
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Genetically encoded fluorescent indicators for imaging intracellular potassium ion concentration
摘要： Potassium ion (K+) homeostasis and dynamics play critical roles in biological activities. Here we describe three genetically encoded K+ indicators. KIRIN1 (potassium (K) ion ratiometric indicator) and KIRIN1-GR are F?rster resonance energy transfer (FRET)-based indicators with a bacterial K+ binding protein (Kbp) inserting between the fluorescent protein FRET pairs mCerulean3/cp173Venus and Clover/mRuby2, respectively. GINKO1 (green indicator of K+ imaging) is a single fluorescent protein-based K+ indicator constructed by insertion of Kbp into enhanced green fluorescent protein (EGFP). These indicators are suitable for detecting K+ at physiologically relevant concentrations in vitro and in cells. KIRIN1 enabled imaging of cytosolic K+ depletion in live cells and K+ efflux and reuptake in cultured neurons. GINKO1, in conjunction with red fluorescent Ca2+ indicator, enable dual-color imaging of K+ and Ca2+ dynamics in neurons and glial cells. These results demonstrate that KIRIN1 and GINKO1 are useful tools for imaging intracellular K+ dynamics.
关键词： FRET-based sensors,potassium ion imaging,single fluorescent protein sensors,intracellular K+ dynamics,genetically encoded indicators
更新于2025-11-21 11:24:58
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Discovery of Turn-On Fluorescent Probes for Detecting Bcl-2 Protein
摘要： Bcl-2 (B cell lymphoma-2 gene) family proteins play a central role in regulating programmed cell death. In cancer, anti-apoptotic Bcl-2 proteins, such as Bcl-2 and Mcl-1, are overexpressed. However, there are few developed labeling techniques for tracing the dynamic processes of Bcl-2. To study the physiological process of Bcl-2 protein, a novel series of small molecule fluorescent probes (1-3) were designed and evaluated for their labeling properties. It’s interesting that our probes can be applied to identify tumor tissue slices and differentiate the tumor and normal tissues effectively, a feature that renders these probes compatible for future cancer diagnosis in clinical practice.
关键词： fluorescent probes,cell imaging,Bcl-2 protein
更新于2025-11-21 11:24:58
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Design and synthesis of a new fluorescent probe for cascade detection of Zn <sup>2+</sup> and H <sub/>2</sub> PO <sub/>4</sub><sup>?</sup> in water and targeted imaging of living cells
摘要： Design and synthesis of new fluorescence probes with good water‐solubility is of great importance to better understanding the significant role of ions which are related to biology and the environment. As important ions, zinc ion (Zn2+) and dihydrogen phosphate ion (H2PO4?) display essential roles in living systems, and quantitative detection of these ions in water is still a challenge. In order to consider the significant role of the galactose moiety in the design of a water‐soluble fluorescence sensor, herein, we have developed a novel probe, Gal‐AQTF, for the cascade detection of Zn2+ and H2PO4? with excellent selectivity in water. Through the introduction of the galactose moiety onto the sensor AQTF, which has been reported earlier by us, the water‐solubility, cell compatibility and targeting ability were enhanced. Gal‐AQTF has been successfully applied in the imaging of the living cells of HepG2 and A549, and illustrated good selectivity for the HepG2 cells which overly express the asialoglycoprotein (ASGP) receptor.
关键词： targeted imaging,Galactose,Zn2+ and H2PO4?,in water,fluorescent probe
更新于2025-11-21 11:24:58
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Green Fluorescent Protein-Based Glucose Indicators Report Glucose Dynamics in Living Cells
摘要： Glucose is the most important energy source for living animals. Here, we developed a series of single fluorescent protein (FP)-based glucose indicators, named as "Green Glifons", to understand the hierarchal and mutual relationships between molecules involved in energy metabolism. Three indicators showed a different EC50 for glucose (50 μM, 600 μM and 4,000 μM), producing a ~7-fold change in fluorescence intensity in response to glucose. The indicators could visualize glucose dynamics in the cytoplasm, plasma membrane, nucleus and mitochondria of living HeLa cells and in vivo, in the pharyngeal muscle of C. elegans and could measure murine blood glucose levels. Finally, the indicators were applicable to dual-color imaging, revealing the dynamic interplay between glucose and Ca2+ in mouse pancreatic MIN6 m9 β cells. We propose that these indicators will facilitate and contribute to in vivo and multi-color imaging of energy metabolism.
关键词： biosensors,artificial sweeteners,dual-color imaging,C. elegans,live cell imaging,glucose,blood glucose level,fluorescent protein
更新于2025-11-21 11:24:58
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Immobilization of Detonation Nanodiamonds on Macroscopic Surfaces
摘要： Detonation nanodiamonds (NDs) are a novel class of carbon-based nanomaterials, and have received a great deal of attention in biomedical applications, due to their high biocompatibility, facile surface functionalization, and commercialized synthetic fabrication. We were able to transfer the NDs from large-size agglomerate suspensions to homogenous coatings. ND suspensions have been used in various techniques to coat on commercially available substrates of pure Ti and Si. Scanning electron microscopy (SEM) imaging and nanoindentation show that the densest and strongest coating of NDs was generated when using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide (EDC/NHS)-mediated coupling to macroscopic silanized surfaces. In the next step, the feasibility of DNA-mediated coupling of NDs on macroscopic surfaces is discussed using fluorescent microscopy and additional particle size distribution, as well as zeta potential measurements. This work compares different ND coating strategies and describes the straightforward technique of grafting single-stranded DNA onto carboxylated NDs via thioester bridges.
关键词： detonation nanodiamonds,bio-conjugation,fluorescent microscopy,de-agglomeration,nanoindentation
更新于2025-11-21 11:24:58
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Intriguing “chameleon” fluorescent bioprobes for the visualization of lipid droplet-lysosome interplay
摘要： The interplay of lipid droplets (LDs) and lysosome plays an important role in cell metabolism, and the visualization of this process can provide useful information of organelle communication and function. However, fluorescent bioprobes based on organic fluorophores that can respond to LD-lysosome interplay are much rare. Herein, fluorescent bioprobes with high photostability, excellent biocompatibility and intracellular polarity sensitivity are achieved by encapsulating a new red fluorogenic molecule TPA-BTTDO within polymeric matrix (DSPE-PEG2000). They can sequentially localize in lysosome and LDs with red and cyan emissions, respectively. By monitoring the emission color change, the interesting dynamic processes of the probes escaping from lysosome and then enriching in LDs, and finally returning to lysosome after LDs consumption are visualized. In addition, the tracing of dynamic movement and consumption of LDs is realized by the probes with a high signal-to-noise ratio. The unique labeling behaviors and distinguished dual emissions of the probes in LDs and lysosome make them promising agents for fluorescence visualization studies of LD-lysosome related bioprocess and metabolism diseases.
关键词： lipid droplet,aggregation-induced emission,nanomaterials,lysosome,fluorescent bioprobe
更新于2025-11-21 11:08:12
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A novel peptide-based fluorescent chemosensor for Cd(II) ions and its applications in bioimaging
摘要： Nowadays, it is of great significance to develop a novel fluorescent chemosensor for Cd(II) ions detection with cost-effective, rapid, facile and applicable to environment and biological milieus. Herein, we report a new peptide-based fluorescent chemosensor DSC (Dan-Ser-Cys-NH2) based on dipeptide (Ser-Cys-NH2) conjugated with dansyl group, which was synthesized using solid phase peptide synthesis (SPPS) technology. As designed, DSC exhibited fluorescent “turn-on” response for Cd2+ in 100% aqueous solution over a wide range of pH values based on photoinduced electron transfer (PET). The stoichiometry binding of DSC and Cd2+ was determined to be 2:1 by Job’s plot and ESI-MS analysis. Furthermore, DSC showed highly sensitive for Cd2+ and a low detection limit of 13.8 nM. What's more, DSC has cell permeability and low cytotoxicity, and fluorescence imaging experiments demonstrated that DSC was capable of monitoring Cd2+ in living HK2 cells by confocal microscopy.
关键词： Fluorescent chemosensor,Cell imaging,Cd(II) ions,Dansyl group,Dipeptide
更新于2025-11-21 11:08:12
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Long-distance tracing of the lymphatic system with a CT/fluorescence dual-modality nanoprobe for surveying tumor lymphatic metastasis
摘要： Noninvasive visualization of deep tissue lymphatic metastasis is crucial for diagnosing malignant tumors and predicting prognosis. However, the limited diffusivity and specificity of imaging contrast agents that are transported in lymph vessels (LVs), even for those agents delivered by nanocarriers, make long-distance tracing of the lymphatic system in vivo challenging. Here, we develop a CT/fluorescence dual-modality phospholipid nanoprobe (PL(I/D)NP) with a negative charge and sub-60 nm size. By using micro-CT, we noninvasively traced the LVs from the subcutaneous injection site in feet to the thoracic ducts with an entire length of ~68 mm and measured the volume of the lymph nodes (LNs) and their separation distance along the LVs. For diagnostic imaging of tumor lymphatic metastasis, all LNs with metastasis were identified in vivo. Thus, with their long-distance diffusivity, high lymphatic capillary specificity and quantifiability, the PL(I/D)NPs combined with noninvasive imaging accurately depicted the changes in the lymphatic system under pathologic conditions, especially cancer metastasis, which indicates their high potential for clinical applicability.
关键词： lymphatic system,nanoparticle,fluorescent imaging,micro-CT,lymphatic metastasis
更新于2025-11-21 11:08:12