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Biologically‐active near‐ultraviolet emitting spirooxindole‐pyrrolidine/pyrrolothiazole‐β‐ketothiolester have been synthesised via Chemo‐/regio‐/stereoselective manner. Excited‐state intramolecular proton transfer (ESIPT) of β‐ketothiolester exhibits excitation‐dependent emission with intermolecular hydrogen bonding ability with solvents. The emission could be tunable between 330 nm to 460 nm. Selected fluorescent compounds 4{4,2,1}, 4{12,2,2}, 5{4,2,1} and 5{12,2,2} shows cytotoxicity effect on PC3 cells, where the highest IC50 value (6 μM) was found for the probe 5{12,2,2}. The fluorescent behavior of 5{4,2,1} and 5{12,2,2} acted as an imaging molecule against cancer cells. [ABSTRACT FROM AUTHOR]

Aza-BODIPY biotin-based nano-self-assembly has been designed with a biotin receptor for selective NIR turn-on fluorescence activity against cancer cells. The nanostructured aza-BODIPY assemblies exhibit distinctive fluorescence characteristics via an avidin-induced partial disintegration process. The in vitro studies for nanoprobes NSA-DPR1a and NSA-DPR1b showed effective recognition and can discriminate biotin receptor-positive cancer cells (MDA-MB-231 and MCF7) compared to non-cancerous cells (MCF10A). [ABSTRACT FROM AUTHOR]

γ-Glutamyltranspeptidase (γ-GGT), as a key enzyme, exhibits markedly higher expression levels in tumor cells compared to normal cells. Under normal conditions, γ-GGT activity on the cell membrane is relatively low, but it undergoes a significant upregulation in cancer cells, making it a potential cancer biomarker. Particularly in A549 cells, a prominent cancer cell line, the pronounced upregulation of γ-GGT expression emphasizes its potential as a unique recognition target and a robust marker for A549 cells. This study successfully synthesized a highly selective γ-GGT fluorescent probe, the exhibits commendable sensitivity (LOD = 0.0021U/mL) and selectivity, achieving efficient detection at the cellular level and providing accurate insights into differential expression between normal and cancer cells. The alterations in fluorescence lifetime observed before and after the probe's reaction with γ-GGT serve as a crucial foundation for fluorescence lifetime imaging on living cells. The probe has become a powerful tool for precise localization of tumor cells, particularly demonstrating its capability for specific recognition in A549 cells. Overall, this research highlights the potential of γ-GGT as a target for fluorescent probes, emphasizing its prospects in specific recognition, particularly in A549 cells, with profound implications for advancing early cancer diagnosis and treatment methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • LD-VP emits fluorescence at 520 nm in dioxane and 600 nm in viscous media without any interference from biological entities. • The LD-VP probe is pH-independent. • The quantum yield of probe LD-VP has changed from 0.5 % to 30% as the viscosity rises from 0.9 cP to 953 cP. • Probe LD-VP has provided green images in nonpolar intracellular milieu detection and red images for high viscosity. • Probe LD-VP concurrently labeled mitochondria, lysosomes, and lipid droplets in red and green channels based on intracellular viscosity and polarity. The viscosity and polarity of cells are inherent physical parameters, and changes to these attributes are frequently linked to malfunctioning conditions or different diseases. Cancer cells often harbor elevated nonpolar lipid droplets (LDs), acting as energy reserves. The rise in lipid droplets (LDs) and viscosity, distinctive traits of cancer cells, has motivated us to develop a fluorescent probe based on naphthalimide. The fluorescent marker LD-VP exhibits fluorescence signals at 520 nm in nonpolar dioxane and 600 nm in highly viscous glycerol. This implies that probe LD-VP can furnish details regarding cellular microviscosity and lipid droplets within live cells by providing dual-channel images. The probe LD-VP is chemically inert and harmless, enabling its safe utilization in live cell imaging. We conducted fluorescence imaging based on viscosity using probe LD-VP in the red channel, which is found to be co-localized in both mitochondria and lysosomes. Moreover, the probe effectively marks lipid droplets in the green channel. The probe LD-VP represents a distinctive fluorescent tool capable of monitoring both viscosity and lipid droplet expression in live cells. This tool holds the potential for visualizing physiological abnormalities or pathological conditions. [ABSTRACT FROM AUTHOR]

A purely organic supramolecular assembly emitting three‐photon room‐temperature phosphorescence (RTP) is constructed from a macrocyclic host, cucurbit[8]uril (CB[8]), and 4‐bromophenyl pyridine salt having an alkyl chain length of 6 or 12 carbon atoms (6C and 12C, respectively). Benefiting from macrocyclic host confined guests, the encapsulation of 12C and 6C in the CB[8] cavity results in three‐photon absorption and subsequent near‐infrared (NIR) phosphorescence emission. Notably, secondary assembly with sulfonated β‐cyclodextrin (SCD) further enhances the phosphorescence emission of the multilevel supramolecular assembly. NIR‐delayed fluorescence via a light‐harvesting phosphorescent energy transfer system is achieved by adding Nile blue as a substrate. Comparison of 12C/CB[8]/SCD and 6C/CB[8]/SCD shows that a long hydrophobic layer is more conducive to stabilizing NIR‐delayed fluorescence emission. These findings indicate that multilevel supramolecular assemblies can be used for three‐photon‐excited NIR‐delayed fluorescence and RTP imaging of cancer cells, which greatly expands the biological applications of pure organic RTP materials. [ABSTRACT FROM AUTHOR]

Lipid droplets (LDs) have emerged as a hot target for cancer therapeutics in recent years owing to findings that have shown them to be key organelles involved in maintaining cellular stability and regulating inter-organelle communication through molecular trafficking. LDs emerge from the endoplasmic reticulum (ER) as a form of cellular homeostasis control. We herein report the study of a library of asymmetric squaraines as superior fluorescence probes to track and image LDs in their native state and environment within cancer cells. The probes are highly selective towards LDs and displayed prominent bright fluorescence with just 1 μM probe concentration. They also possess bimodal LD and ER staining capability via the simple diffusion of small lipophilic molecules. The probes almost instantly stained LDs, while the ER staining rate is dependent on the probe's lipophilicity and the incubation duration. These "on-demand" organelle-selective probes are highly desirable tools for revealing the role of LDs in governing many cellular processes, especially in malignant cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The probe P-1 can selectively detect H 2 O 2 with colorimetric change. • the P-1 can be used for on-site and visual detection of H 2 O 2. • The P-1 can image H 2 O 2 in cells and distinguish cancer cells and normal cells. • The P-1 probe was applied to monitor H 2 O 2 of tumor in mice. We designed and developed the probe P-1 for detecting H 2 O 2. The probe can selectively detect H 2 O 2 with colorimetric change. In addition, the combination of portable test strips with a smartphone platform provided great convenience for on-site and visual detection of H 2 O 2 with satisfactory sensitivity and reliability. The P-1 can image exogenous and endogenous H 2 O 2 in cells and distinguish cancer cells and normal cells by fluorescence image of H 2 O 2 and flow cytometry. Meanwhile, the P-1 probe has been successfully applied to monitor H 2 O 2 levels of tumor in mice, and the results showed the level of H 2 O 2 in tumor tissue increased significantly. Therefore, P-1 provided a potential chemical tool to understand pathological and physiological mechanisms of diseases by imaging H 2 O 2. [ABSTRACT FROM AUTHOR]

The utilization of nanomaterial-based probes in detecting glutathione (GSH) and cell imaging has aroused extensive attention owing to the excellent properties of nanoprobes. Herein, we have synthesized manganese dioxide-S, O co-doped graphitic carbon nitride quantum dots (MnO2-S, O-CNQDs) nanocomposite by in situ synthesis of MnO2 nanosheets in S,O-CNQDs dispersion solution. It was found that GSH could specifically bind to MnO2-S, O-CNQDs so that the fluorescence of S, O-CNQDs could be recovered. As such, a "turn-on" MnO2-S, O-CNQDs nanoprobe can be fabricated and applied to rapidly determine trace amounts of GSH. Under the optimal conditions, MnO2-S, O-CNQDs shows sensitive response to GSH in the range 10–270 μM with a detection limit of 0.307 μM (S/N = 3). The developed MnO2-S, O-CNQDs probe has demonstrated great potential to detection of GSH in biological samples and glutathione injections. What is more, MTT assay indicates that MnO2-S, O-CNQDs has low biotoxicity. The non-fluorescence MnO2-S, O-CNQDs reacts with GSH to recover the fluorescence of S, O-CNQDs in HepG2 cells. Thus, the "turn-on" fluorescence change of MnO2-S, O-CNQDs offers a potentially useful tool to monitor GSH of cancer cells. [ABSTRACT FROM AUTHOR]

Inside living cells, regulation of catalytic activity of artificial enzymes remains challenging due to issues such as biocompatibility, efficiency, and stability of the catalyst, by which the practical applications of artificial enzymes have been severely hindered. Here, an artificial enzyme, PTT‐SGH, with responsiveness to reactive oxygen species (ROS), was obtained by introducing a catalytic histidine residue to pentaerythritol tetra(3‐mercaptopropionate) (PTT). The artificial enzyme formed large aggregates in cells via the intracellular ROS‐mediated oxidation of thiol groups. The process was significantly facilitated in tumor cells because of the higher ROS concentration in the tumor microenvironment. The catalytic activity of this artificial enzyme was intensively enhanced through deprotonation of cross‐linked PTT‐SGH, which showed typical esterase activities. Selective fluorescence imaging of tumor cells was achieved using the artificial enzyme to trigger the cleavage of the ester bond of the caged fluorophore inside living cells. [ABSTRACT FROM AUTHOR]

Cancer represents a leading cause of death worldwide. Hence, a better understanding of the molecular mechanisms causing and propelling the disease is of utmost importance. Several cancer entities are associated with altered K+ channel expression which is frequently decisive for malignancy and disease outcome. The impact of such oncogenic K+ channels on cell patho-/physiology and homeostasis and their roles in different subcellular compartments is, however, far from being understood. A refined method to simultaneously investigate metabolic and ionic signaling events on the level of individual cells and their organelles represent genetically encoded fluorescent biosensors, that allow a high-resolution investigation of compartmentalized metabolite or ion dynamics in a non-invasive manner. This feature of these probes makes them versatile tools to visualize and understand subcellular consequences of aberrant K+ channel expression and activity in K+ channel related cancer research. [Display omitted] • K+ ions and K+ channels modulate cancer malignancy. • K+ channels are located throughout (intra-) cellular membranes. • Fluorescent biosensors allow high resolution imaging of subcellular signaling events. • Biosensors are valuable tools to investigate metabolic consequences of oncogenic K+ channels. [ABSTRACT FROM AUTHOR]

The fabrication of silver nanoclusters with good cellular uptaking behaviors and the property of easy separation and redispersion without aggregation is a thorny problem. In this work, the nanosilica supported silver nanoclusters were prepared by method of situ photochemical reduction of silver precursor on the carboxylated silica nanoparticles. The composite silver nanoclusters showed excellent fluorescent emission properties, good photostability and can be separated from aqueous phase by centrifugation, then can be redispersed in the water environment without affecting its fluorescence emission properties. Further, the vitro cancer cell imaging experiments showed that the composite silver clusters have good cellular uptaking behaviors and excellent biocompatibility. Thus, the composite silver cluster showed good potential application prospects in the field of biomarkers. [ABSTRACT FROM AUTHOR]

A novel NIR probe based on oxazolonaphthoimidazo[1,2- a ]pyridine-malononitrile (ONIM) conjugate linked by vinyl linkage was designed and synthesized for the detection of cyanide ion. [Display omitted] • An orange emitting sensor ONIM (712 nm) with D-π-A framework is synthesized. • The ONIM emission is retained in the solid state. • ONIM could sense cyanide ion without interference of other anions. • Sensing mechanism of cyanide sensing was confirmed by 1H NMR and DFT calculations. • Live cell imaging in human breast cancer cell MDA-MB 231 and as solid state sensor was achieved. Cyanide is undoubtedly dangerous and fast acting chemical employed in various industrial applications with toxic side effects, which raises urgent need for its monitoring. In this context, oxazolonaphthoimidazo[1,2- a ]pyridine-malononitrile (ONIM) conjugate linked by vinyl linkage was designed, synthesized and characterised by FT-IR, NMR and mass spectrometry. The developed probe has been evaluated for the colorimetric and fluorometric detection of cyanide ion. An obvious color change with unique rapid " turn-off " fluorometric response was observed within 5 s upon addition of CN– thus reflecting its better acuteness and sensitivity over other competing anions. The developed probe exhibits a detection limit of 9.54 nM which is very low in comparison to maximum permitable amount of cyanide in drinking water (1.9 µM). The probe is stable within the p H range of 2–9 and suitable for the recognition of CN– in the p H range of 7 to 10, specially at neutral p H conditions. The chemodosimetric approach based detection mechanism was authenticated by 1H NMR titration and DFT calculations. The solid state applications were established by utilising ONIM impregnated TLC plates and filter paper in cyanide recognition. The solid state emissive behaviour of ONIM offers on-spot detection of the cyanide anion. Additionally, the practicability of ONIM has been extended in live cell imaging of CN– in human breast cancer cell (MDA-MB-231), which revealed a " turn-off " fluorescence response for the probe in the presence of CN– ion. [ABSTRACT FROM AUTHOR]

A novel cancer cell and lysosome dual-targeted photosensitizer (PS) termed by BMP was developed for fluorescence imaging and photodynamic therapy (PDT). BMP consists of a porphyrin(Zn) core with appropriate singlet-triplet state distribution enables it to function as an imaging agent as well as a PS, a biotin moiety that can target cancer cells, and a morpholine group specific to lysosomes. Intracellular experiments demonstrated that the dual-targeted photosensitizer BMP could preferably accumulate in cancer cells and subsequently locate within lysosome organelles. Upon irradiation, BMP could generate red fluorescence emission (Φ em = 6.3%) and singlet oxygen (1O 2 , Φ Δ = 55%) for the dual functionality of cell imaging and PDT, respectively. Notably, BMP exhibited much higher photocytotoxicity toward cancer cells (A549 cells) compared to normal cells (BEAS-2B cells). Importantly, 1O 2 produced by BMP induced oxidative damage of lysosomes, and subsequently triggered cell death of A549 cells, as evidenced by the loss of morphological integrity and cell rupture. A cancer cell and lysosome dual-targeted photosensitizer BMP was designed to generate red emission and singlet oxygen (1O 2) simultaneously, which were utilized successfully for dual-targeted fluorescence imaging and photodynamic therapy. [Display omitted] • A dual-targeted photosensitizer was designed and synthesized by modularization. • Biotin acted as a targeting ligand for cancer cells, and morpholine was selected as the lysosome-specific group. • Red fluorescence and singlet oxygen generation were achieved for fluorescence imaging and PDT of cancer cells simultaneously. [ABSTRACT FROM AUTHOR]

Fluorescent carbon dots (CDs) were prepared for targeted cancer imaging and in vivo imaging. The CDs were prepared via one-step hydrothermal pyrolysis of urea and sodium citrate dihydrate. The CDs revealed nice crystalline structure, excellent aqueous stability and good photoluminescence property and high quantum yield. The fluorescent images indicated that the anti-HE4-CDs were specifically internalized by the HO-8910 ovarian cancer cells. Furthermore, the CDs revealed vivid fluorescent signal in the animal imaging test and promising potential in brain imaging. Finally, the CDs also suggested low toxicity after treatment for 1 day, 7 days and 21 days. Therefore, the prepared CDs could be a promising imaging probe for targeted cancer cell imaging and in vivo imaging. Fluorescent carbon dots were prepared for targeted cancer imaging and in vivo imaging. The CDs were prepared via one-step hydrothermal pyrolysis of urea and sodium citrate dihydrate with excellent aqueous stability, good photoluminescence property and high quantum yield. The CDs revealed vivid fluorescent signal in the animal imaging test and promising potential in brain imaging. [ABSTRACT FROM AUTHOR]

Photostable and near‐infrared (NIR)‐emitting organic fluorophores with large Stokes shifts are in great demand for long‐term bioimaging at deeper depths with minimal autofluorescence and self‐quenching. Herein, a new class of benzorhodamines and their analogues that are photostable and emit in the NIR region (up to 785 nm) with large Stokes shifts (>120 nm) is reported. The synthesis involves condensation of 7‐alkylamino‐2‐naphthols with 2‐[4‐(dimethylamino)‐2‐hydroxybenzoyl]benzoic acid, which leads to bent‐shaped benzorhodamines that emit orange fluorescence (≈600 nm); however, introduction of steric hindrance near the condensation site switched the regioselectivity, to provide a linear benzorhodamine system for the first time. The linear benzorhodamine derivatives provide bright fluorescence images in cells and in tissue. A carboxy‐benzorhodamine was applied for photothermal therapy of cancer cells and xenograft cancer mice. [ABSTRACT FROM AUTHOR]

A unique fluorescence chemosensing method has been introduced to explain a new strategy for simultaneous selective determination of cysteine and serine in two different emission channels through an "on‐off‐on" mechanism. Dansyl chloride‐picolylamine conjugate (DNPC) ensembles with Cu2+ (DNPC‐Cu2+) and shows a turn‐on fluorescence while binding with serine or cysteine. Fluorescence, NMR titrations and DFT calculations has been performed in order to understand the sensing mechanism and the electronic properties of the receptor‐donor complex. The chemosensing method has been successfully applied in human cancer cells to detect and quantify cysteine and serine differentially. [ABSTRACT FROM AUTHOR]

The anticancer mechanism of NO is difficult to study owing to its short lifetime and high reactivity. Thus, a theranostic anticancer NO donor assembled with NO on-demand release abilities, accurate lysosome location capabilities and signal feedback behavior was developed. Profiting from the theranostic properties, the specific mechanism was comprehensively studied. Spectral and cell imaging studies revealed that the as prepared NO donors could release NO in solution or within cancer cells. Fluorescence co-dyeing experiments demonstrated that Mo-Nap-NO entered lysosomes specifically and disrupted them after being triggered by light. Upon irradiation with 460 nm visible light, both the donors demonstrated considerable in vitro anticancer effects. A further mechanistic study showed that after entering the lysosome and being triggered by 460 nm irradiation, NO ruptured the lysosome, resulting in the release of cathepsin D into the cytosol, which activated the caspase3 mediated apoptosis pathway. [ABSTRACT FROM AUTHOR]

Protein C receptor (PROCR) is a recently discovered transmembrane biomarker for several tissue stem cells and is highly expressed in triple-negative breast cancer (TNBC) patient-derived xenografts. Herein, to enrich the toolbox for the biochemical evaluation of PROCR, we have developed a peptide-functionalized fluorogenic 2D material based on the self-assembly between a fluorescent peptide probe and thin-layer molybdenum disulfide. The material developed was suitable for the sensitive detection of PROCR recombinant protein in buffer solution and the fluorescence imaging of TNBC cells that express high levels of PROCR. [ABSTRACT FROM AUTHOR]

Fluorogenic substrates are used to visualize the activity of cancer-associated enzymes and to interpret biological events. Certain types of glutathione S-transferase (GST), such as Pi class GST (referred to as GSTP1), are more highly expressed in a wide variety of human cancer tissues compared to their corresponding normal tissues. Pi class GST is thus a cancer cell molecular marker and potential target for overcoming resistance to chemotherapy. Here, we report that 4-bromo-1,8-naphthalimide (BrNaph) is a practical fluorogenic GST substrate. We have found that HE-BrNaph , an N -hydroxyethyl derivative, shows remarkable fluorescence enhancement upon GST-catalyzed S N Ar replacement of the bromo group with a glutathionyl group. This substitution was highly selective and occurred only in the presence of GSH/GSTs; no non-enzymatic reaction was observed. We demonstrated that HE-BrNaph allows visualization of GST activity in living cells and enables to distinguish cancer cells from normal cells. Further, various N -substitutions in BrNaph retain susceptibility to enzymatic activity and isozyme selectivity, suggesting the applicability of BrNaph derivatives. Thus, BrNaph and its derivatives are GST substrates useful for fluorescence imaging and the intracellular detection of GSTP1 activity in living cells. Image 1 • HE-BrNaph shows a large fluorescence enhancement upon catalysis by GST. • HE-BrNaph was used for live cell imaging of GSTP1 activity. • Various N -substitutions in BrNaph were tolerated by the enzymatic reaction and maintained isozyme selectivity. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO) has been studied on the treatment of numerous diseases such as cancers, rheumatoid arthritis, and so on. However, real-time tracking and controlled release of CO gas for a safe and efficient therapy are till a challenging task. Although many CO-releasing molecules (CORMs) have been widely developed and used because of the release of CO by external stimuli, CORMs still have some disadvantages, such as fast CO release, potential toxicity and poor solubility. Herein, light-triggered CO-releasing hybrid material (UIO-66-NH 2 /CORM@FA-CS-5-FAM) based on UIO-66-NH 2 nanoparticles and [Mn(CO) 3 (CH 3 CN)(HPYDC)]·CH 3 CN (H 2 PYDC = 2, 5-pyridinedicarboxylic acid, abbreviated as CORM) coated with FA-CS-5-FAM was constructed. The composition characteristics of the hybrid material include: a chitosan (CS) increases the residence time of drugs on the application/absorption sites, folic acid (FA) targets the cancer cells and 5-carboxyfluorescein (5-FAM) is used as an imaging agent. Comparison with the free CORM, UIO-66-NH 2 /CORM@FA-CS-5-FAM nanocomposite exhibits a long-time CO release and possesses the excellent characteristics of targeted cancer cells and fluorescence imaging. Cell viability assays indicate that UIO-66-NH 2 /CORM@FA-CS-5-FAM shows good biocompatibility and anticancer activity. Light-triggered CO-releasing hybrid material (UIO-66-NH 2 /CORM@FA-CS-5-FAM) exhibits a long-time CO release and possesses the excellent characteristics of targeted cancer cells and fluorescence imaging. [Display omitted] • UIO-66-NH 2 /CORM@FA-CS-5-FAM nanocomposite exhibits a long-time CO release irradiated by UV and visible light. • The nanocomposite possesses the excellent characteristics of targeted cancer cells and fluorescence imaging. • The nanocomposite shows good biocompatibility and anticancer activity. [ABSTRACT FROM AUTHOR]

Fluorescent carbon quantum dots (CQDs) can be prepared by sonochemistry with low cost and high efficiency. However, ultrasonic synthesis of CQDs with responsive fluorescence towards environmental stimuli remains a big challenge. Herein, we report a simple one-step method to fabricate versatile nitrogen-doped CQDs (NCQDs) by ultrasonic treatment of dopamine in dimethylformamide for 8 h. The obtained NCQDs simultaneously possess superior water dispersibility and stability, bright and stable fluorescence against variations of pH and ionic strength, low cytotoxicity and high photostability. Moreover, the fluorescence of NCQDs showed sensitive quenching phenomenon towards Fe2+ ions both in water and in the interior of cancer cells. The emission intensity of NCQDs exhibited good linear relationship (R 2 = 0.9987) with the concentration of Fe2+ ions in the range of 0–50 μM. The limit of detection can reach as high as 38 nM. Meanwhile, the NCQDs also exhibited temperature-dependent fluorescence with favorable linear relationship (R 2 = 0.9965) in the range of 283–358 K, and thus can server as a nanothermometer to sense temperature both in water and in cells. Unlabelled Image • Ultrasonic synthesis of versatile fluorescent NCQDs from dopamine was reported. • NCQDs showed high water dispersibility, stable fluorescence, and low cytotoxicity. • The fluorescence of NCQDs exhibited sensitive quenching behavior towards Fe2+ ions. • N-CQDs also presented temperature-dependent fluorescence behavior. [ABSTRACT FROM AUTHOR]

In this study, a pH-sensitive fluorescent probe was created through the host-guest assembly of an amphiphilic hydroxyphenyl benzotriazole derivative (HBT-11) and cucurbit[7]uril (CB7). The fluorescence of HBT-11 is highly dependent on the molar ratio (r) of CB7 to HBT-11. If r < 1, the peak positions remain unchanged while the intensity increases with r. If r > 1, the emission peaks shift to longer wavelengths. The complexation also results in a shift in the p K a of HBT-11. The 1:1 mixture of CB7 and HBT-11 has a p K a close to neutral pH. The supramolecular probe allows for discrimination of malignant A549 and benign HEK 293T cells owing to a pronounced 8-fold light-up effect in malignant A549 cells attributed to the pH-responsive fluorescence. Given that the selective light-up mechanism is based on the pH-sensitive fluorescence of the supramolecular probe, this approach is expected to be applicable to other cancer cells. [Display omitted] • A pH-sensitive supramolecular fluorescence probe was constructed. • The fluorescent intensity of the probe was greatly enhanced as pH < p K a. • The probe was applied to discriminate malignant and benign cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • This nanozyme demonstrates H 2 O 2 -responsive turn-on fluorescence imaging. • The POD-like activity is 229.9% higher than the natural peroxidase enzyme (Horseradish Peroxidase, HRP) • The double-benefit is achieved through a self-regulating electron transfer process. The detection and treatment based on tumor microenvironment (TME) are essential in cancer therapy. Currently, nanomaterials with mimic-enzyme property have attracted tremendous interest and the regulation of the sensing and catalytical activity inside the living cells remains a challenge. Herein, a reactive oxygen species (ROS) driven nanozyme, with selective activated fluorescence imaging and multiple enzyme activity (including peroxidase, superoxide dismutase and catalase), was achieved via the confinement of CDs on the ultrathin CuAl-LDH (denoted as CDs/LDHzyme). This unique CDs/LDHzyme demonstrate H 2 O 2 -responsive turn-on fluorescence via the self-regulating electron transfer process between Cu2+ and CDs. Furthermore, generated Cu+ through this electron transfer process can be beneficial for the POD-like activity, resulting an outstanding catalytic efficiency with the maximum initial velocity (V max) as high as 2.002 × 10−7 M s−1, which is 229.9% higher than the natural peroxidase enzyme (Horseradish Peroxidase, HRP). Structure characterization and energy level calculation can further prove the mechanism of this self-regulating electron transfer process. These findings open an avenue to enable the utilization of nanozyme as a remedial nanoplatform to the selective fluorescence imaging and nanozyme-initiated chemodynamic therapy (NCDT). [ABSTRACT FROM AUTHOR]

Fluorescent probes sensitive to microenvironments have constantly been attractive, due to their significant benefits in monitoring changes in the pathophysiological microenvironment and their use in the early detection of associated disorders. In this work, we explored three new molecular rotors that could be potential candidates for detecting lipid droplets (LDs) in cancer cells based on coumarin derivatives connected with electron-donating polycyclic units including, tetraphenylethylene (LD-TPE), pyrene (LD-PYR), and 4,5-diphenylimidazole (LD-DIP). Gratifyingly, LD-PYR showed exceptional polarity and viscosity sensitivity and demonstrated bright fluorescence in highly viscous environments due to the suppression of the twisted intramolecular charge transfer (TICT) phenomenon and intramolecular rotation. Moreover, microenvironment-guided specific LD bioimaging by LD-PYR exhibited a reasonable ability to distinguish between cancer and noncancer cells. These data suggested that LD-PYR has interesting clinical diagnostic and microenvironment-related biological applications. [Display omitted] • Highly polarity and viscosity-sensitive fluorescence probes have been introduced. • LD-PYR probe shows bright fluorescence in a lipophilic environment due to TICT suppression. • LD-PYR demonstrates good biocompatibility in both cancer cell and normal cell lines. • LD-PYR can selectively image lipid droplet in cancer cells. [ABSTRACT FROM AUTHOR]

Benefiting from the excellent photostability and biocompatibility, fluorescent nanoclusters have recently emerged as a highly attractive bio-sensing and imaging material, especially in early diagnosis of cancer. However, their clinic applications were limited by the unsatisfactory specificity and the complex synthesis. In this study, novel methionine coated gold nanoclusters (Met-AuNCs) have been prepared via an easily-achievable one-pot synthetic method. The prepared Met-AuNCs showed high imaging-specificity: after incubating with Met-AuNCs for 1 h, cancer cells (including A549, Hela, MCF-7, HepG2) were fluorescent, while the normal cells (WI-38 and CHO) showed no fluorescence. According to a series of controlled experiments, the reason for the high imaging-selectivity was proposed to originate from the specific recognition of L-type amino acid transporter overexpressed in cancer cells. [ABSTRACT FROM AUTHOR]

This work reports an approach for imaging the localization, distribution, and level of miRNA in different organelles based on an activated fluorescence signal triggered by an alteration of the specific binding-induced conformation of the designed activatable probe. We selected miR-150 as an miRNA example to image its localization, distribution, and level in human cervical cancer cells (HeLa cells). The results indicate that miR-150 is localized and distributed in different subcellular organelles (mainly in mitochondria and lysosomes) and that its levels (actually its concentrations) in lysosomes are higher than those in mitochondria in both HeLa and MCF-7 cells. Moreover, the level of miRNA in cells is displayed in a height-dependent (in z-direction) manner. This approach can also be used to image the localization and distribution of various miRNAs (such as miR-150 and miR-214) in different organelles in cancer cells simultaneously. The probes exhibit high resistance to cellular endo- and exonucleases, with high specificity; the capability of avoiding false signals, with a high signal-to-background ratio; and a good ability to operate in complicated environments. The developed approach may provide a useful tool for studying the localization and distribution and evaluating the level of multiple tumor-related miRNAs in cells. [ABSTRACT FROM AUTHOR]

Particles which bear tumor cell targeting and multimode imaging capabilities are promising in tumor diagnosis and cancer therapy. A simple and versatile method to fabricate gold/polydopamine-Methylene Blue@Bovine Serum Albumin–glutaraldehyde–Transferrin composite particles (Au/PDA-MB@BSA-GA-Tf NPs) for tumor cell targeting and fluorescence (FL) / surface-enhanced Raman scattering (SERS) dual-modal imaging were reported in this work. Polydopamine (PDA) spheres played an important role in gold ion reduction, gold nanoparticle (Au NPs) binding and methylene blue (MB) adsorption, MB were employed as both fluorescence label and Raman reporter. In addition, glutaraldehyde (GA) crosslinked bovine serum albumin (BSA) in the outer layer of Au/PDA-MB nanoparticles can prevent MB from dissociation and leakage. The composite nanoparticles were further conjugated with transferrin (Tf) to target transferrin receptor (TfR)-overexpressed cancer cells. The targeting ability as well as the intracellular location of the probe was investigated through SERS mapping and fluorescence imaging. Their excellent biocompatibility was demonstrated by low cytotoxicity against breast cancer cell (4T1 cell). [ABSTRACT FROM AUTHOR]

Conjugated polymer nanoparticles have been regarded as promising fluorescent materials for biological application, due to their high emission efficiency, good photostability and low cytotoxicity. In this contribution, we synthesized a conjugated polymer which integrates blue-, green- and red-emitting components into the backbone in an appropriate molar ratio. After being transferred from solution to nanoparticles, its fluorescence color turns from blue to pink with enhanced fluorescence quantum yield. After incorporation of an amphiphilic polymer as matrix, white-emissive polymer nanoparticles are obtained as a result of optimized energy transfer degree among the three components. Finally, their good performance on cell imaging are demonstrated by incubation with HeLa cells, after being proved to be safe for biological application. [ABSTRACT FROM AUTHOR]

Fluorescence imaging with tumor-specific fluorescent probe has emerged as a tool to aid surgeons in the identification and removal of tumor tissue. We report here a new lysosome-targeting fluorescent probe (NBOH) with BODIPY fluorephore to distinguish tumor tissue out of normal tissue based on different pH environment. The probe exhibited remarkable pH-dependent fluorescence behavior in a wide pH range from 3.0 to 11.0, especially a sensitive pH-dependent fluorescence change at pH range between 3.5 and 5.5, corresponding well to the acidic microenvironment of tumor cells, in aqueous solution. The response time of NBOH was extremely short and the photostability was proved to be good. Toxicity test and fluorescence cell imaging together with a sub-cellular localization study were carried out revealing its low biotoxicity and good cell membrane permeability. And NBOH was successfully applied to the imaging of tumor tissue in tumor-bearing mice suggesting potential application to surgery as a tumor-specific probe. [ABSTRACT FROM AUTHOR]

Nowadays, cancer has become a serious threat to public health worldwide. Early and precise diagnosis is critical for the detection, monitoring and management of cancer. Herein, a facile strategy for developing a fluorescence/MRI dual-modal nanoprobe (FA-PEI-NaGdF 4 :Eu nanoparticles) has been reported for targeted cancer cell imaging. The fluorescence/MRI nanoprobes have strong fluorescence and the high signal-to-noise ratio, which is suitable for the fluorescence imaging. Moreover, the FA-PEI-NaGdF 4 :Eu nanoprobes have high longitudinal relaxivity, making them suitable for T 1 -weighted MR imaging. Additionally, due to modification with FA, the fluorescence/MRI nanoprobes could target cancer cells that possessed large numbers of folate receptors. The results of the cytotoxicity assay revealed that the nanoprobes had the excellent biocompatibility. With the high biocompatibility, excellent imaging performance and superior targeting, the FA-PEI-NaGdF 4 :Eu nanoprobes can be used as a promising candidate for targeted fluorescence/MRI cancer cell imaging and would bring more opportunities for the biomedical applications. [ABSTRACT FROM AUTHOR]

Surface modified ZnO nanomaterial is widely used in the field of bioimaging worldwide due to its optical properties, electronic characteristics and biocompatibility. Fluorescent enhanced, Polyquaternium-7(PQ7) capped, ZnO hexagonal nano disks (ZnO-PQ7) were synthesised by simple wet chemical method. The structural and optical properties of ZnO-PQ7 hexagonal nano disks were characterized using XRD, UV-Visible, Fluorescence, HRTEM, EDAX and FTIR studies. The size of synthesised ZnO-PQ7 were around 30-45 nm as confirmed by HRTEM studies. Fluorescence emission intensity increased with increase in PQ7 concentration. ZnO-PQ7 was further conjugated with folic acid (FA) to target human breast cancer cell line (MCF-7) via EDC/NHS coupling chemistry. Conjugation of folic acid with ZnO-PQ7 was confirmed by FTIR studies. The cell viability study using Methyl thiazolyltetrazolium(MTT) assay has demonstrated that the ZnO-PQ7 conjugated FA composites (ZnO-PQ7-FA) exhibit low toxicity towards MCF-7 up to a concentration of 125 μg/mL. Confocal laser scanning microscopic images confirmed the uptake of ZnO-PQ7-FA nanoparticles by MCF-7 cells. This study reveals ZnO-PQ7-FA nano disks as a potential imaging agent for detection of cancer cells. The synthesis route reported in this article is simple and easy to follow for the synthesis of ZnO-PQ7-FA in bulk quantities with high purity. [ABSTRACT FROM AUTHOR]

HClO is recognized as an indicator for phagocytosis and inflammatory response. Excess HClO ruptures lysosomes and leads to cell apoptosis, which has been proposed as a cure for cancer treatment. As a consequence, the real-time and in situ cell imaging for HClO is highly appealed in the field of anticancer pharmacy. In this work, a series of silane-modified rhodamine fluorescers with various functional groups were designed, hoping to find a fluorescer with near IR emission for bio-imaging in live cells, along with unique sensing response towards ClO− over competing species. These silane-modified rhodamine fluorescers were carefully characterized, their photophysical parameters and responses towards ClO− and competing species were compared systematically. An optimal probe showed emission quantum yield of 0.26 with emission wavelength at 681 nm. Emission "turn-on" effect was observed, with calibration equation of F = 0.720*[ClO−]2+40.047*[ClO−]+54.982, R2 = 0.999, and the limit of detection (LOD) was calculated as 0.03 μM. Corresponding sensing mechanism was revealed as an HClO-mediated cyclization reaction. Fluorescence imaging for Hela cells and A549 lung cancer cells was performed. The lysosome-targetable feature was confirmed. • A series of silane-modified rhodamine fluorescers with near IR emission for bio-imaging in live cells were reported. • An optimal probe showed emission quantum yield of 0.26 with emission wavelength at 681 nm. • Sensing calibration equation was a non-linear one and the limit of detection (LOD) was calculated as 0.03 μM. • Sensing mechanism was revealed as an HClO-mediated cyclization reaction. [ABSTRACT FROM AUTHOR]

Aptamer-functionalized fluorescent silver nanoclusters (Ag NCs) possessing specific recognition ability of aptamer and fluorescence emissions have been developed for applications in biorelated areas. However, only one color emission hampered their further use in multiplexed analysis. To address this issue, AS1411 aptamer-tagged Ag NCs with green color emissions and MUC 1 aptamer-tagged Ag NCs with yellow color emissions were synthesized by one-pot approach in this work. With the rational design of the DNA template and optimization of the synthetic buffer, as well as the NaBH 4 -to-Ag + ratio, the growth time and purity of the obtained aptamer-functionalized Ag NCs were improved. Under the optimal conditions, the quantum yields of AS1411 aptamer-functionalized green Ag NCs and MUC 1 aptamer-functionalized yellow Ag NCs were 20.33% and 8.65% with 9,10-diphenyl anthracene and fluorescein as the reference standards, respectively. The green and yellow emission properties of Ag NCs were related to the surface oxidation states of the Ag NCs. Furthermore, the binding ability of AS1411 aptamer and MUC 1 aptamer to cancer cells enabled specific cellular imaging. Aptamer-functionalized Ag NCs with multicolor emissions could broaden the applications of Ag NCs in multiplexed analysis and multicolor imaging of tumor cells, especially with the selection of more targeted aptamers. [ABSTRACT FROM AUTHOR]

A simple and efficient fluorescent chemosensor for Al 3 + is reported in the paper. The chemosensor is obtained by dehydration reaction of 2-hydroxy-1-naphthaldehyde and 2-aminophenol. The chemosensor has high selectivity and sensitivity for Al 3 + and displays fluorescence “off–on” switch signal. The detection limit of the chemosensor for Al 3 + can reach 1.0 × 10 − 7 M in DMSO/H 2 O (1:9, v/v) solution. The mass spectra and Job's plot analysis confirm the 1:1 stoichiometry between chemosensor and Al 3 + . Potential utilization of the probe as an intracellular sensor of Al 3 + in human cancer (HiSa) cells is also examined by confocal fluorescence microscopy. [ABSTRACT FROM AUTHOR]

Fluorescence recognition of Zn in 100 % aqueous medium using 2-((1, 3 dihydroxy-2-(hydroxymethyl)propan-2 ylimino) methyl) phenol (SALTM) as ratiometric probe is reported. Moreover, SALTM can discriminate Zn from Cd very effectively. The binding constant and detection limit of the probe for Zn is 2.2 × 10 M and 2.79 × 10 M respectively. Interestingly, corresponding naphthalene derivative (HNTM) having less water solubility fails to be a ratiometric sensor. SALTM can detect intracellular Zn in HeLa cervical cancer cells under fluorescence microscope. Moreover, DFT and TD-DFT studies support experimental findings. [ABSTRACT FROM AUTHOR]

Achieving highly selective and sensitive detection/visualization of intracellular biological events through the use of cell-penetrable, bioanalyte-activatable, tum-on probes is dependent on the presence of specific event-linked cellular biomarkers, if and only if there exist activatable probes that appropriately respond to the biomarker analyte. Here is described the evaluation of, and use in cellular imaging studies, a previously undisclosed naphthalimide probe QMeNN, whose fluorescence is deactivated by photoinduced electron transfer (PeT) quenching that results from the presence of a covalently linked biomarkerspecific quinone trigger group. Highly selective and rapid activation of the quinone group by the human cancer tumor-linked NAD(P)H:quinone oxido-reductase isozyme 1 (hNQO1) results in fast trigger group removal to yield a highly fluorescent green-energy-range reporter that possesses a high molar absorptivity; there is a 136-fold increase in brightness for the enzymatically produced reporter versus probe precursor, a value 4 times greater than previously reported for the hNQO1 analyte. The novel probe is taken up and activated rapidly within only hNQO1 -positive human cancer cells; addition of an hNQO1 inhibitor prevents the selective activation of the probe. Comparison of cytosolic fluorescence intensity in positive cells versus background in negative cells yields a quantitative metric (positive-to-negative ratio, PNR) for judging hNQO1 activity. We show it is possible to determine hNQOl presence in previously studied colorectal cancer cells and the unexplored ovarian cancer cell line NIH:OVCAR-3, with respective PNR values of 926 and 34 being obtained. Even with 10 min probe incubation, ready discrimination of positive cells from negative cells is achieved. Cell viability is unaffected by probe presence, thereby highlighting the practicality of probe use in live-cell imaging applications. [ABSTRACT FROM AUTHOR]

T cells are pivotal in the immune defense against cancers and infectious agents. To mount an effector response against cancer cells, T cells need to migrate to the cancer-site, engage in contacts with cancer cells, and perform their effector functions. Adoptive T cell therapy is an effective strategy as treatment of complications such as relapse or opportunistic infections after hematopoietic stem cell transplantations. This requires a sufficient amount of cells that are able to expand and respond to tumor or viral antigens. The cytokines interleukin (IL)-2 and IL-7 drive T cell differentiation, proliferation, and survival and are commonly used to expand T cells ex vivo. Here, we have used microchipbased live-cell imaging to follow the migration of individual T cells, their interactions with allogeneic monocytes, cell division, and apoptosis for extended periods of time; something that cannot be achieved by commonly used methods. Our data indicate that cells grown in IL-7+IL-2 had similar migration and contact dynamics as cells grown in IL-2 alone. However, the addition of IL-7 decreased cell death creating a more viable cell population, which should be beneficial when preparing cells for immunotherapy. [ABSTRACT FROM AUTHOR]

Hypoxia is a trait that widely exists in 90% of solid tumors. Under hypoxic conditions, biological reductase enzymes in tumors will be overexpressed (e.g., azoreductase). This feature is often used to design fluorescence probes to recognize hypoxic cells from normoxic cells. The presently reported fluorescence probes are mostly designed by covalent bonds, which requires tedious synthesis. In this study, a fluorescence nanoprobe was prepared by encapsulating azobenzene into assemblies of polymeric amphiphiles bearing fluorophores (denoted by PAF). The nanoprobes without azobenzene are strongly emitted in aqueous solution, and the emission was effectively quenched when azobenzene was included in the nanoprobes. The nanoprobes with azobenzene showed quite different emission intensities when cultured in hypoxic and normoxic cells, leading to fluorescence quantum yields (QYs) of 18.0% vs. 1.5%, respectively. Here, we demonstrated a facile method to prepare an azoreductase-responsive fluorescent nanoprobe that can selectively light up malignant cells from benign cells. [Display omitted] • A turn-on fluorescence probe is designed by supramolecular assembly. • The probe has good light stability, high selectivity and excellent biocompatibility. • The probe was successfully applied to selectively light up malignant cells. [ABSTRACT FROM AUTHOR]

In this study, we describe a solutionprocedure for the preparationand surface modification of photostable colloidal silicon quantumdots (SiQDs) for imaging of cancer cells. Photoluminescent SiQDs weresynthesized by reduction of halogenated silane precursors using amicroemulsion process. It was shown that 1,8-nonadiyne molecules couldbe grafted onto the surface of hydrogen-terminated SiQDs via ultraviolet(UV)-promoted hydrosilylation, demonstrated by Fourier transform infraredspectroscopy (FTIR) measurements. In addition, various azide moleculeswere coupled onto nonadiyne-functionalized particles, rendering particlesdispersible in selected polar and nonpolar solvents. The photoluminescenceof functionalized SiQDs was stable against photobleaching and didnot vary appreciably within biologically applicable pH and temperatureranges. To demonstrate compatibility with biological systems, water-solubleSiQDs were used for fluorescent imaging of HeLa cells. In addition,the SiQDs were shown to be non-cytotoxic at concentrations up to 240μg/mL. The results presented herein provide good evidence forthe versatility of functionalized SiQDs for fluorescent bioimagingapplication. [ABSTRACT FROM AUTHOR]

A novel simple and green method was developed to synthesize highly luminescent carbon dots using ascorbic acid as a carbon source in aqueous solution. The as-prepared C-dots showed downconversion and upconversion fluorescence properties. They were applied to imaging of human breast cancer cells and normal human mammary cells, showing low cytotoxicity and good biocompatibility. [ABSTRACT FROM AUTHOR]

Abstract: Herein, one multifunctional AS1411-functionalized fluorescent gold nanoparticles (named NAANPs) is synthesized and successfully applied for both targeted cancer cell imaging and efficient photodynamic therapy (PDT). The NAANPs are obtained by functionalizing the gold nanoparticles with AS1411 aptamer and then bound with one porphyrin derivative N-methylmesoporphyrin IX (NMM). Using HeLa cells over expressing nucleolin as representative cancer cells, the formed NAANPs can target to the cell surface via the specific AS1411-nucleolin interaction, which can discriminate the cancer cells from normal ones (e.g. HEK293) unambiguously. That the fluorescence intensity of NMM increased significantly upon binding to AS1411 G-quadruplex makes the NAANPs appropriate fluorescence reagent for cell imaging. Meanwhile, NMM can also be used as a photosensitizer, thus irradiation of the NAANPs by the white light from a common electric torch can lead to efficient production of cytotoxic reactive oxygen species for establishing a new type of PDT to cancer cells. Gold nanoparticles play the roles of both carrier and enhancer of the functional groups onto the cells. In addition, they not only possess inherently certain cytotoxicity to the cancer cells, but also boost the cellular uptake of the fluorescent groups. As a result, the efficiency of both the targeted cell imaging and PDT could be ensured. [Copyright &y& Elsevier]

Abstract: Multifunctional fluorescent silica nanoparticles with phenylboronic acid tags were developed for labeling sialic acid on the surface of living cancer cells. In this paper, fluorescent silica nanoparticles (FSNPs) with strong and stable emission at 515nm were firstly prepared through a reverse microemulsion process, and then modified with highly selective phenylboronic acid (PBA) tags on their surface via an aqueous ‘thiol-ene’ click reaction. These nanoparticles had a hydrodynamic diameter of 92.6±9.1nm, and a bright fluorescence signal, which is 366 times higher than that of a single dye molecule. Meanwhile, these PBA-tagged FSNPs were found very stable in aqueous solution as well as in cell culture medium, verified by transmission electron microscopy, X-ray photoelectron spectroscopy and zeta potential analysis. The over-expressed sialic acid (SA) on the membrane of living HeLa cells was visualized in situ by a confocal laser scanning microscopy, ascribed to the specific interaction between PBA and SA. Thus, the PBA-FSBPs showed a great potential in probing SA expressed on living cells with high selectivity and sensitivity. [Copyright &y& Elsevier]

Abstract: A new phenanthrene based chemosensor has been synthesized and investigated to act as highly selective fluorescence and visual sensor for Cu2+ ion with very low detection limit of 1.58nM; this has also been used to image Cu2+ in human cervical HeLa cancer cells. [Copyright &y& Elsevier]

Abstract: We report fluorescence behavior in non-functionalized carbon nanoparticles (NCNP) prepared from lamp soot and their application in imaging of normal and cancer cells. Structural characterization of these particles by Raman spectroscopy showed characteristic peaks located at 1350 and 1590cm−1 corresponding to the diamond-like (D) and graphite-like (G) bands of the carbon allotropes respectively with the characteristic ratio I D /I G =2.24. X-ray diffraction study confirmed the presence of amorphous as well as graphitized carbon in these nanostructures with minimum grain size ≈2nm. A typical luminescence lifetime measured by time resolved fluorescence spectroscopy was obtained 3.54ns. The photoluminescence behavior of these particles was excitation dependent and gave off blue, green and red fluorescence under UV, blue and green excitation, respectively. Cellular uptake of these NCNP yielded excellent results for cell imaging of human embryonic kidney, lung carcinoma and breast adenocarcinoma cells. Cell imaging was further correlated with cytotoxicity in the above mentioned cell lines and also in leukemia cell lines. Dose dependant cytotoxicity was observed after 24h up to 48h of incubation of nanoparticles. Fluorescence microscopy of nanoparticle-cell interaction clearly indicated aggregation of the particles. [Copyright &y& Elsevier]

Abstract: An organic chromophore (4-[N, N- bis(2′-chloroethyl)anilino] ethenyl N-methyl pyridinium-N- methyl iodide) L was synthesized and fully characterized by elemental analysis, IR, 1HNMR spectra and single crystal X-ray diffraction analysis. One and two-photon fluorescence spectra for it were studied. Interestingly, L exhibited obvious two-photon absorption in the range from 700–850nm in DMSO solution. The interactions between the chromophore and calf thymus DNA were investigated by absorption, fluorescence spectra and viscosity experiments. The results showed that the chromophore could interact with DNA in the mode of intercalation and be effectively used as fluorescent staining dye for cell imaging applications. Furthermore, the cell viability data for MCF-7 (Human breast carcinoma) cells indicated that the low-micromolar concentrations of the L are essentially non-toxic and can be applied in brighter two-photon fluorescent (TPF) bioimaging. [Copyright &y& Elsevier]