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A computational examination of two new polypyridyl ruthenium complexes, containing meldola blue (MDB) and nile blue (NB) chromophores, is here reported in order to assess the applicability of phenoxazine‐containing complexes in photodynamic therapy (PDT). The designed complexes, named Ru‐3ENB and Ru‐3EMDB, are based on a recently synthesized Ru(II)‐based complex bearing a bipyridyl‐ethynyl‐Nile Red (NR) ligand and proposed for PDT applications. DFT outcomes elucidated how the replacement of NR with MDB induces a red shift of the maximum absorption wavelength within the therapeutic window, up to 638 nm. A change in the molecular orbitals involved in the population of excited states was observed upon chromophore substitution that results in ISC kinetic significantly faster than that computed for the synthesized complex Ru‐3ENR. [ABSTRACT FROM AUTHOR]

Nile blue has been widely used in histological staining, fluorescence labeling, and DNA probing, with its intercalation behavior into the DNA helix being well documented. Here, we present a comprehensive investigation to address a current knowledge gap regarding the binding properties of Nile blue to two types of double-stranded RNA (dsRNA): poly(A·U) and poly(I·C), using various biophysical techniques. Absorption and fluorescence spectroscopic studies suggest a significant binding interaction between Nile blue and the two designated dsRNAs, specifically indicating an intercalation binding mode with poly(A·U) and demonstrating a noticeably higher binding affinity compared to poly(I·C). The binding stoichiometry was further determined by Job's plot to be 0.47 for poly(A·U) and 1.0 for poly(I·C). The increased relative viscosity and changes in the circular dichroism (CD) ellipticity of dsRNA after interacting with Nile blue indicate the stacking of Nile blue dyes between the RNA duplexes. These changes suggest a conformational alteration of the dsRNAs and confirm the intercalation mode of binding. The thermal dynamic analysis demonstrates that both binding were favored by negative enthalpy and primarily driven by the hydrophobic effect.

Silver and gold are the most used plasmonic metals for surface-enhanced Raman spectroscopy (SERS), accounting for the vast majority of the published literature in this field. These two metals are preferred due to their excellent plasmonic enhancement, stability, and relative ease of synthesis and functionalization of their associated nanostructures. However, both silver and gold face earth abundance limitations, and so alternatives should be sought, particularly for large-scale plasmonic applications such as plasmon-enhanced photovoltaics or optical cloaking. In this work, a method to produce effective and scalable copper-based substrates for electrochemical SERS (EC-SERS) is introduced, utilizing commercially available carbon screen-printed electrodes (SPE) and physical vapor deposition (PVD). The carbon black particles present on the working electrode of the SPE serve as an efficient scaffold for the fabrication of copper nanostructures. Several test molecules were used to illustrate the performance of these sensors in the SERS analysis. This work also highlights the first reported formation of an electrochemically generated N-heterocyclic carbene (NHC) self-assembled monolayer (SAM) on a nanostructured copper surface under potential control in an aqueous electrolyte. [ABSTRACT FROM AUTHOR]

Targeted medicine uses the distinctive features of cancer cells to find and destroy tumors. We present human epidermal growth factor receptor 2 (HER2)-targeted PLGA–chitosan nanoparticles for cancer therapy and visualization. Loading with two near-infrared (NIR) dyes provides imaging in the NIR transparency window and phototherapy triggered by 808 nm light. Nile Blue (NB) is a biocompatible solvatochromic NIR dye that serves as an imaging agent. Laser irradiation of IR-780 dye leads to a temperature rise and the generation of reactive oxygen species (ROS). Resonance energy transfer between two dyes allows visualization of tumors in a wide range of visible and IR wavelengths. The combination of two NIR dyes enables the use of nanoparticles for diagnostics only or theranostics. Modification of poly(lactic-co-glycolic acid) (PLGA)–chitosan nanoparticles with trastuzumab provides an efficient nanoparticle uptake by tumor cells and promotes more than sixfold specificity towards HER2-positive cells, leading to a synergistic anticancer effect. We demonstrate optical imaging of the HER2-positive mouse mammary tumor and tumor-specific accumulation of PLGA–IR-780–NB nanoparticles in vivo after intravenous administration. We managed to achieve almost complete suppression of the proliferative activity of cells in vitro by irradiation with an 808 nm laser with a power of 0.27 W for 1 min at a concentration at which nanoparticles are nontoxic to cells in the dark. [ABSTRACT FROM AUTHOR]

Developing combined cancer therapy strategies is of utmost importance as it can enhance treatment efficacy, overcome drug resistance, and ultimately improve patient outcomes by targeting multiple pathways and mechanisms involved in cancer growth and progression. Specifically, the potential of developing a combination chemo&photothermal therapy using targeted polymer nanoparticles as nanocarriers offers a promising approach for synergistic cancer treatment by combining the benefits of both therapies, such as targeted drug delivery and localized hyperthermia. Here, we report the first targeted anti-HER2 PLGA nanocarriers, called targosomes, that simultaneously possess photothermal, chemotherapeutic and diagnostic properties using only molecular payloads. Biocompatible poly(lactic- co -glycolic acid), PLGA, nanoparticles were loaded with photosensitizer phthalocyanine, diagnostic dye Nile Blue, and chemotherapeutic drug irinotecan, which was chosen as a result of screening a panel of theragnostic nanoparticles. The targeted delivery to cell surface oncomarker HER2 was ensured by nanoparticle modification with the anti-HER2 monoclonal antibody, trastuzumab, using the one-pot synthesis method without chemical conjugation. The irradiation tests revealed prominent photothermal properties of nanoparticles, namely heating by 35 °C in 10 min. Nanoparticles exhibited a 7-fold increase in binding and nearly an 18-fold increase in cytotoxicity for HER2-overexpressing cells compared to cells lacking HER2 expression. This enhancement of cytotoxicity was further amplified by >20-fold under NIR light irradiation. In vivo studies proved the efficacy of nanoparticles for bioimaging of primary tumor and metastasis sites and demonstrated 93% tumor growth inhibition, making these nanoparticles excellent candidates for translation into theragnostic applications. [Display omitted] • The first targeted PLGA for chemo&photothermal therapy (targosomes) is reported. • HER2-specificity of targosomes results in excellent bioimaging capabilities. • Chemo&photothermal therapy via targosomes is promising for cancer treatment. [ABSTRACT FROM AUTHOR]

The presence of toxic pollutants in the aquatic environment is a significant environmental concern that requires the development of effective methods for their removal. This study focuses on applying perylene and triazine-based porous organic polymer (PT-POP) to effectively eliminate hazardous pollutants from industrial settings. Specifically, PT-POP was synthesized using two monomers, namely 3,4,9,10 perylenetetracarboxylic dianhydride (PTCDA) and 2,4,6 tris(hydrazino)-s-triazine (THTZ). The resulting PT-POP has outstanding adsorption performance and high chemical and thermal stability, making it an attractive adsorbent material. Based on the thermogravimetric analysis, it has been confirmed that PT-POP is thermally stable. The presence of aromatic rings in PT-POP is responsible for the extraordinary stability of the polymer. Then, the performance of PT-POP in the adsorption of cationic Nile blue and anionic Direct Fast Scarlet 4BS (DFS-4BS) was studied. The optimization process involves adjusting several factors, including temperature, concentration, pH, time, and adsorbent dosage. The highest adsorption capacities (qM) for the Nile blue dye and the DFS-4BS dye were 280.16 mg. g−1 and 87.50 mg. g−1, respectively. The adsorption behavior best fits the pseudo-second-order kinetic model, and the Langmuir isotherm showed the most agreement with adsorption isotherms for both. The thermodynamic study shows that the adsorption process for both dyes is spontaneous and endothermic, as evidenced by the negative value of ΔG and the positive value of ΔH. The findings show that PT-POP is more inclined toward cationic dyes due to its negative surface charge.

In this study, we synthesized carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide) copolymer hydrogels and carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide)/kaolin nanocomposite with a free radical mechanism to adsorb pollutants of Nile blue dye. Nanocomposite hydrogels performed best at pH = 11, a temperature of 25 °C, a contact time of 90 min, a concentration of pollutant 10 ppm, and an adsorbent dose of 1.5 mg. The increased adsorption rate of NB dye pollutants after adding kaolin-type clay nanoparticles from 96.49 to 98.91% showed the successful addition of nanoparticles to hydrogel copolymer structures. The best isotherm performance was the Langmuir isotherm model, and maximum adsorption capacity for carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide) copolymer hydrogels and for carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide) nanocomposite hydrogel was 138.49 and 149.82, respectively. In the analysis of kinetic models, Elovich's kinetic model had the best performance, where the α value for carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide) copolymer hydrogels are 0.783 and for carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide)/kaolin nanocomposite hydrogel obtained a value of 9.58, which indicates a high adsorption value. On the other hand, the enthalpy parameters (ΔH°) for adsorption process using carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide) and carboxymethyl cellulose-graft-poly(methacrylic acid-co-acrylamide)/kaolin nanocomposite hydrogels were − 61.512 kJ/mol and − 77.281 kJ/mol, respectively. The negativity of ΔH° indicates that the process is exothermic at 5–50 °C using both adsorbers. Furthermore, this process could be spontaneous because the Gibbs free energy (ΔG°) for adsorption processes was negative in experiment temperature range. [ABSTRACT FROM AUTHOR]

Background/aim: Photodynamic therapy (PDT) has received great attention over the past decade in the treatment of diseases such as leukemia which is a cancer of the blood and bone marrow cells that causes a significant number of deaths worldwide. In this study, it was aimed to investigate the effects of Nile blue-mediated PDT (NB-mediated PDT) on HL60 cells. Materials and methods: The effect of NB-mediated PDT on cell proliferation was evaluated with cell volume analysis using flow cytometry at 24 h. Cell apoptosis, ROS production, mitochondrial membrane potential, and cell cycle analysis were evaluated using annexin V-FITC, H2 DCFDA, JC-1, and PI staining, respectively, by flow cytometry and fluorescence microscopy. The morphological and ultrastructural analyses were examined by Giemsa staining and SEM. CD11b staining is used to determine the differentiation of leukemia cells. Results: NB-mediated PDT induced an apoptotic response at 12.5 µM in HL60 cells. When Giemsa staining and SEM images were evaluated, apoptotic bodies, holes, and occasional folds were detected on the surfaces of cells in the NB-mediated PDT group. Conclusion: The NB-mediated PDT had no effect on the differentiation of leukemia cells, but this therapy affects the growth of HL60 cells in vitro, which may provide a new idea for removing leukemic cells from bone marrow intended for autologous transplant. [ABSTRACT FROM AUTHOR]

The unique discriminating ability of hydroxyapatite (HAP) to single- and double-stranded nucleic acid implies its potential as a biosensing material for nucleic acid analysis. Herein, a novel immobilization- and label-free electrochemical strategy has been developed for miRNA let-7a detection based on the specific adsorption of magnetic Fe3O4@hydroxyapatite (Fe3O4@HAP) to a duplex structure. Typically, the highly efficient homogeneous reaction between probe DNA (pDNA) and target miRNA let-7a produces the nucleic acid duplex, which is specifically adsorbed on the surface of Fe3O4@HAP. Thereafter, the electroactive intercalator Nile blue (NB) is introduced as the label-free signal molecule and inserts between the stacked base pairs of the pDNA–miRNA duplex. Thus, the Fe3O4@HAP bearing pDNA–miRNA and numerous intercalated NBs are adsorbed by the magnetic glassy carbon electrode, giving rise to an intense sensing signal without the need of nuclease-assisted cyclic amplification. With this advantage, the sensing system shows a wide linear range from 1.0 fM to 100 nM and a low detection limit of 0.051 fM for miRNA let-7a analysis. What is more, the synergy of the base-pairing-driven hybridization, the specific intercalation of NB to the duplex structure, and the selective adsorption of Fe3O4@HAP contribute to a high sensing specificity of the biosensing strategy. The sensing method provides a state-of-the-art strategy for the sensitive and facile bioanalysis and clinical diagnosis of miRNA. [ABSTRACT FROM AUTHOR]

Therapy for aggressive metastatic breast cancer remains a great challenge for modern biomedicine. Biocompatible polymer nanoparticles have been successfully used in clinic and are seen as a potential solution. Specifically, researchers are exploring the development of chemotherapeutic nanoagents targeting the membrane-associated receptors of cancer cells, such as HER2. However, there are no targeting nanomedications that have been approved for human cancer therapy. Novel strategies are being developed to alter the architecture of agents and optimize their systemic administration. Here, we describe a combination of these approaches, namely, the design of a targeted polymer nanocarrier and a method for its systemic delivery to the tumor site. Namely, PLGA nanocapsules loaded with a diagnostic dye, Nile Blue, and a chemotherapeutic compound, doxorubicin, are used for two-step targeted delivery using the concept of tumor pre-targeting through the barnase/barstar protein "bacterial superglue". The first pre-targeting component consists of an anti-HER2 scaffold protein, DARPin9_29 fused with barstar, Bs-DARPin9_29, and the second component comprises chemotherapeutic PLGA nanocapsules conjugated to barnase, PLGA-Bn. The efficacy of this system was evaluated in vivo. To this aim, we developed an immunocompetent BALB/c mouse tumor model with a stable expression of human HER2 oncomarkers to test the potential of two-step delivery of oncotheranostic nano-PLGA. In vitro and ex vivo studies confirmed HER2 receptor stable expression in the tumor, making it a feasible tool for HER2-targeted drug evaluation. We demonstrated that two-step delivery was more effective than one-step delivery for both imaging and tumor therapy: two-step delivery had higher imaging capabilities than one-step and a tumor growth inhibition of 94.9% in comparison to 68.4% for the one-step strategy. The barnase*barstar protein pair has been proven to possess excellent biocompatibility, as evidenced by the successful completion of biosafety tests assessing immunogenicity and hemotoxicity. This renders the protein pair a highly versatile tool for pre-targeting tumors with various molecular profiles, thereby enabling the development of personalized medicine. [ABSTRACT FROM AUTHOR]

The demand for new fluorophores for different biological target imaging is increasing. Benzo[a]phenoxazine derivatives are fluorochromophores that show promising optical properties for bioimaging, namely fluorescent emission at the NIR of the visible region, where biological samples have minimal fluorescence emission. In this study, six new benzo[a]phenoxazinium chlorides possessing sulfonamide groups at 5-amino-positions were synthesized and their optical and biological properties were tested. Compared with previous probes evaluated using fluorescence microscopy, using different S. cerevisiae strains, these probes, with sulfonamide groups, stained the vacuole membrane and/or the perinuclear membrane of the endoplasmic reticulum with great specificity, with some fluorochromophores capable of even staining the plasma membrane. Thus, the addition of a sulfonamide group to the benzo[a]phenoxazinium core increases their specificity and attributes for the fluorescent labeling of cell applications and fractions, highlighting them as quite valid alternatives to commercially available dyes. [ABSTRACT FROM AUTHOR]

In this study, an alternative precursor for production of biomass-derived activated carbon was introduced using dragon fruit (Hylocereus costaricensis) peels. Chemical activators such as FeCl3, MgCl2, ZnCl2 were used in the thermal carbonization process to convert carbon into porous carbon (PC). However, heteroatom-doped PC catalysts including N-, B-, and P-doped carbon catalysts in the field of dye removal is highly desirable. Several approaches (XRD, FE-SEM/TEM, XPS, FT-IR, EDS, and elemental mapping) were employed to examine the surface morphology, surface properties, and elemental composition of the PC catalyst. The catalytic activity of metal-free PC catalyst was demonstrated for methylene blue (MB), crystal violet (CV), and Nile blue (NB) in a mild environment The corresponding rate constant (kapp) values were estimated as 0.2473, 0.3248, and 0.3056 min−1, respectively, for MB, CV, and NB, which were significantly greater than those of numerous reports. It exhibited the best catalytic activity and recyclability. Moreover, the approach proposed here could create new opportunities for the remediation of organic dyes in lakes and industrial wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • The inclusion complex of Nile blue (NB) with p -sulfonatothiacalix[4]arene (TSC4X) was prepared using co-precipitation method. • Various spectroscopic methods such as FTIR, 1H NMR, TGA etc., have been utilized to characterise the formation of inclusion complex. • The molecular association constant was found to be 2720 M−1 at 298.15 k. • Molecular Docking study has also been performed. • BSA binding study have been shown as an application of the prepared inclusion complex. Herein, we explored the construction of a supramolecular encapsulated complex between Nile blue (NB) and p-sulfonatothiacalix[4]arene (TSC4X). The developed inclusion complex (NB-TSC4X) was established by fluorescence spectroscopy, TGA, FTIR, 1H NMR, and Docking studies. Benesi-Hildebrand calculation showed a linear plot that indicated a 1:1 stoichiometric ratio having a fairly high stability constant of 2720 M−1 in the solution phase. Docking analysis helps us to find out the optimized structure of the inclusion complex. Finally, the binding interaction of the inclusion complex with bovine serum albumin (BSA) was evaluated. In brief, this work uncloses a new strategy to enhance the performance of fluorescent dye. [ABSTRACT FROM AUTHOR]

Targeted medicine uses the distinctive features of cancer cells to find and destroy tumors. We present human epidermal growth factor receptor 2 (HER2)-targeted PLGA–chitosan nanoparticles for cancer therapy and visualization. Loading with two near-infrared (NIR) dyes provides imaging in the NIR transparency window and phototherapy triggered by 808 nm light. Nile Blue (NB) is a biocompatible solvatochromic NIR dye that serves as an imaging agent. Laser irradiation of IR-780 dye leads to a temperature rise and the generation of reactive oxygen species (ROS). Resonance energy transfer between two dyes allows visualization of tumors in a wide range of visible and IR wavelengths. The combination of two NIR dyes enables the use of nanoparticles for diagnostics only or theranostics. Modification of poly(lactic-co-glycolic acid) (PLGA)–chitosan nanoparticles with trastuzumab provides an efficient nanoparticle uptake by tumor cells and promotes more than sixfold specificity towards HER2-positive cells, leading to a synergistic anticancer effect. We demonstrate optical imaging of the HER2-positive mouse mammary tumor and tumor-specific accumulation of PLGA–IR-780–NB nanoparticles in vivo after intravenous administration. We managed to achieve almost complete suppression of the proliferative activity of cells in vitro by irradiation with an 808 nm laser with a power of 0.27 W for 1 min at a concentration at which nanoparticles are nontoxic to cells in the dark.

Herein, a novel strategy for sensitive determination of uranium in natural water was proposed using electropolymerization of Nile blue modified glassy carbon electrode (PNB/GCE) and differential pulse adsorptive stripping voltammetry (DPAdSV). The preparation of modified electrodes, electrolyte, reproducibility, and substance interferences was studied. The PNB/GCE were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and DPAdSV. The DPAdSV peak current was proportional to the concentration of uranium in the range of 0.30–100 μg·L−1 with the detection limit of 0.19 μg·L−1 and R2 = 0.997. Finally, the PNB/GCE was successfully applied to determination of uranium in natural water samples. [ABSTRACT FROM AUTHOR]

In this study, zeolite clay was modified with Fe-Al LDH (layered double hydroxide or hydrotalcite) under ultrasonic process and was then used to remove methyl violet (MV) and Nile blue (NB) dyes from aqueous media. Various analyses such as FT-IR, EDX, SEM, and XRD were done to evaluate the adsorbent properties. The highest sorption efficiency of MV and NB dyes was 99.15% and 98.16%, respectively, which indicate significant adsorption efficiencies. The highest adsorption efficiency of MV dye was obtained at pH 8, adsorbent dosage of 1 g/L, contact time of 40 min, dye concentration of 20 mg/L and temperature of 25 °C. Also, the highest adsorption efficiency of NB dye was obtained at pH 9, adsorbent dosage of 1.25 g/L, contact time of 40 min, dye concentration of 20 mg/L and temperature of 25 °C. In addition, the maximum adsorption capacity of MV and NB dyes was found to be 81.98 and 60.61 mg/g, respectively, which are significant values. Moreover, the maximum desorption efficiencies of MV and NB were achieved 99.14% and 98.67%, respectively. Furthermore, the sorption mechanism showed that the intraparticle and film diffusion processes are important in the adsorption process. The aforementioned adsorbent can be effectively reused for five consecutive cycles. Equilibrium and kinetic studies indicated that the Freundlich isotherm model and pseudo-second-order kinetic model fit the experimental data well. [ABSTRACT FROM AUTHOR]

Plastic materials originated from petrochemicals causes serious environmental problems due to their non-degradable nature. Bio based polymers or biodegradable polymers are found to be better solution in terms of protecting the environment from petroleum based plastic products. Polyhydroxybutyrates (PHBs) are synthesized and deposited as cytoplasmic inclusions in various bacteria like Bacillus sp. Biodegradable plastic have been available for many years in the market, however, their high cost has meant they have not replaced the traditional non-degradable plastics. The aim of this research is to produce biodegradable plastic by Bacillus sp. using sugarcane bagasse. Pure culture of different isolates obtained from soil, were screened by sub culturing in a modified nutrient agar medium containing glucose and Nile Blue A stain to confirm that the isolated strain were capable of producing PHB. The strain was identified as Bacillus velezensis when subjected to molecular characterization. Optimization of growth parameter such as substrate concentration (0.5, 1, 2, 3 and 4%) and temperature (30, 35, 40, 45 and 50) for production of bioplastic, was further conducted. The maximum PHB accumulation when pretreated sugar cane bagasse was used as carbon source was at 30°C and pH 8.0 after 48h incubations with total yield of 50.23%. Biodegradability test showed that soil borne organism are capable of utilizing the PHB. The results of this study confirmed that cheaply available agro-residues can be used for the production of PHB. [ABSTRACT FROM AUTHOR]

The lipid content of mammalian cells varies greatly between cell type. Current methods for analysing lipid components of cells are technically challenging and destructive. Here, we report a facile, inexpensive method to identify lipid content - intracellular flow cytometric lipid analysis (IFCLA). Distinct lipid classes can be distinguished by Nile Blue fluorescence, Nile Red fluorescence or violet autofluorescence. Nile Blue is fluorescent in the presence of unsaturated fatty acids with a carbon chain length greater than 16. Cis-configured fatty acids induce greater Nile Blue fluorescence than their trans-configured counterparts. In contrast, Nile Red exhibits greatest fluorescence in the presence of cholesterol, cholesteryl esters, some triglycerides and phospholipids. Multiparametric spanning-tree progression analysis for density-normalized events (SPADE) analysis of hepatic cellular lipid distribution, including vitamin A autofluorescence, is presented. This flow cytometric system allows for the rapid, inexpensive and non-destructive identification of lipid content, and highlights the differences in lipid biology between cell types by imaging and flow cytometry. [ABSTRACT FROM AUTHOR]

Therapy for aggressive metastatic breast cancer remains a great challenge for modern biomedicine. Biocompatible polymer nanoparticles have been successfully used in clinic and are seen as a potential solution. Specifically, researchers are exploring the development of chemotherapeutic nanoagents targeting the membrane-associated receptors of cancer cells, such as HER2. However, there are no targeting nanomedications that have been approved for human cancer therapy. Novel strategies are being developed to alter the architecture of agents and optimize their systemic administration. Here, we describe a combination of these approaches, namely, the design of a targeted polymer nanocarrier and a method for its systemic delivery to the tumor site. Namely, PLGA nanocapsules loaded with a diagnostic dye, Nile Blue, and a chemotherapeutic compound, doxorubicin, are used for two-step targeted delivery using the concept of tumor pre-targeting through the barnase/barstar protein “bacterial superglue”. The first pre-targeting component consists of an anti-HER2 scaffold protein, DARPin9_29 fused with barstar, Bs-DARPin9_29, and the second component comprises chemotherapeutic PLGA nanocapsules conjugated to barnase, PLGA-Bn. The efficacy of this system was evaluated in vivo. To this aim, we developed an immunocompetent BALB/c mouse tumor model with a stable expression of human HER2 oncomarkers to test the potential of two-step delivery of oncotheranostic nano-PLGA. In vitro and ex vivo studies confirmed HER2 receptor stable expression in the tumor, making it a feasible tool for HER2-targeted drug evaluation. We demonstrated that two-step delivery was more effective than one-step delivery for both imaging and tumor therapy: two-step delivery had higher imaging capabilities than one-step and a tumor growth inhibition of 94.9% in comparison to 68.4% for the one-step strategy. The barnase*barstar protein pair has been proven to possess excellent biocompatibility, as evidenced by the successful completion of biosafety tests assessing immunogenicity and hemotoxicity. This renders the protein pair a highly versatile tool for pre-targeting tumors with various molecular profiles, thereby enabling the development of personalized medicine.

The morphologies of the internal organs of echinoderm larvae and juveniles are difficult to study using conventional optical microscopes because of their structural complexity and opaqueness. This paper describes an easy and rapid protocol involving Nile blue staining followed by benzyl alcohol/benzyl benzoate (BABB) clearing to overcome this limitation. This method was developed for a three‐dimensional (3D) analysis of the internal structures of advanced larvae and juveniles of echinoderms (the sea lily Metacrinus rotundus, the sea urchin Hemicentrotus pulcherrimus, and the sand dollar Scaphechinus mirabilis) and is suitable for obtaining serial optical images by confocal microscopy without the use of specific antibodies or special reagents for labeling. Nile blue is an easy‐to‐use stain that offers several advantages for confocal microscopy such as it can stain various tissues with strong fluorescent signals without substantial bleaching during observation. We found that the strong fluorescence signal of Nile blue quickly yielded clear high‐resolution optical section images for 3D reconstruction. BABB clearing rendered opaque larvae highly transparent. The clearing procedure was also easy and quick. During the process, agarose embedding prior to staining and clearing was found to be critical for handling the samples of less than 500‐μm length and stabilizing their orientations. To conclude, the protocol described is useful for performing a rapid and accurate 3D morphological analysis of echinoderm larvae and juveniles. [ABSTRACT FROM AUTHOR]

Niemann-Pick type C (NPC) disease is an autosomal recessive lysosomal storage disease that is caused by a mutation of the NPC1 or NPC2 gene, in which un-esterified cholesterol and sphingolipids accumulate mainly in the liver, spleen, and brain. Abnormal lysosomal storage leads to cell damage, neurological problems, and premature death. The time of onset and severity of symptoms of NPC disease are highly variable. The molecular mechanisms that are responsible for NPC disease pathology are far from being understood. The present study generated and characterized a zebrafish mutant that lacks Npc2 protein that may be useful for studies at the organismal, cellular, and molecular levels and both small-scale and high-throughput screens. Using CRISPR/Cas9 technology, we knocked out the zebrafish homolog of NPC2. Five-day-old npc2 mutants were morphologically indistinguishable from wildtype larvae. We found that live npc2–/– larvae exhibited stronger Nile blue staining. The npc2–/– larvae exhibited low mobility and a high anxiety-related response. These behavioral changes correlated with downregulation of the mcu (mitochondrial calcium uniporter) gene, ppp3ca (calcineurin) gene, and genes that are involved in myelination (mbp and mpz). Histological analysis of adult npc2–/– zebrafish revealed that pathological changes in the nervous system, kidney, liver, and pancreas correlated with inflammatory responses (i.e., the upregulation of il1, nfκβ, and mpeg; i.e., hallmarks of NPC disease). These findings suggest that the npc2 mutant zebrafish may be a model of NPC disease.

Many dyes produced during the 19th century were named after locations. Manufacturers proliferated the number of synonyms used and in time, the original names were forgotten. Therefore, in the headings below, the original names are followed by the current name(s) in parentheses. The stories of some of these dyes that survived into the 21st century are recounted here. Numerical identity data are provided. Chemical structures also are provided and for simplicity, ionic structures, which can be multiple and pH variable, are presented as their parents. [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB) is the most widely studied biodegradable plastic that does not release any toxins or residues in the environment like petroleum based plastics. This work has been undertaken to screen PHB accumulating microorganisms from marine sponges and a total of sixteen isolates were collected and purified. Screening of isolated strains was done by Nile blue staining and observed under Leica LSCM to confirm the production of PHB. Yellow pigmented AB8a isolate from Oceanopia arenosa scored positive for PHB accumulation and subjected to morphological, biochemical and phylogenetic characterization. The biopolymer was extracted by dispersion of sodium hypochlorite and chloroform solution and characterized by FT-IR and 1H NMR for the confirmation as PHB. The highest PHB production (70.25%/100 ml) was achieved at pH 7.0 by applying dextrose as medium at incubation temperature 30°C and 150 rpm agitation speed. The FTIR spectrum of the PHB sample showed major peaks at 3457, 1692, 1550, 1454, 1420, 1190 and 1050 cm-1, whereas the remaining peaks are closely laid between 3450 cm-1 and 600 cm-1. ¹H NMR spectrum of PHA isolated from dextrose media indicated characteristic signals of PHB. The spectrum also revealed the presence of three groups of signals characteristic of PHB by the doublet at 1.3 ppm attributed to the methyl group coupled to one proton; and the spectrum of the quadruplet at 2.57 ppm, the methylene group adjacent to an asymmetric carbon atom bearing a single proton and the multiplet at 5.28 ppm indicated signals of PHB. The PHB accumulated bacterium identified as Bacillus flexus strain based on characterization studies and 16S rRNA sequence analysis and confirmed the presence of intracellular accumulated polymer substantiated as PHB. [ABSTRACT FROM AUTHOR]

Niemann-Pick type C (NPC) disease is an autosomal recessive lysosomal storage disease that is caused by a mutation of the NPC1 or NPC2 gene, in which un-esterified cholesterol and sphingolipids accumulate mainly in the liver, spleen, and brain. Abnormal lysosomal storage leads to cell damage, neurological problems, and premature death. The time of onset and severity of symptoms of NPC disease are highly variable. The molecular mechanisms that are responsible for NPC disease pathology are far from being understood. The present study generated and characterized a zebrafish mutant that lacks Npc2 protein that may be useful for studies at the organismal, cellular, and molecular levels and both small-scale and high-throughput screens. Using CRISPR/Cas9 technology, we knocked out the zebrafish homolog of NPC2. Five-day-old npc2 mutants were morphologically indistinguishable from wildtype larvae. We found that live npc2–/– larvae exhibited stronger Nile blue staining. The npc2–/– larvae exhibited low mobility and a high anxiety-related response. These behavioral changes correlated with downregulation of the mcu (mitochondrial calcium uniporter) gene, ppp3ca (calcineurin) gene, and genes that are involved in myelination (mbp and mpz). Histological analysis of adult npc2–/– zebrafish revealed that pathological changes in the nervous system, kidney, liver, and pancreas correlated with inflammatory responses (i.e., the upregulation of il1 , nf κβ, and mpeg ; i.e., hallmarks of NPC disease). These findings suggest that the npc2 mutant zebrafish may be a model of NPC disease. [ABSTRACT FROM AUTHOR]

Conjugation of quantum dot (QD) with oxidized nile blue (NB) is known to be able to strongly decrease fluorescence intensity of QD. In the present study, NB‐conjugated QD (QD‐NB) was functionalized with anti‐human epidermal growth factor receptor 2 aptamer to form aptamer‐functionalized QD‐NB (Apt‐QD‐NB), as a new biosensing platform to monitor aptamer‐dependent internalizations and reduction‐dependent transformations. Our study shows that more QD fluorescence signals in cells can be induced by the specific internalization of higher amounts of Apt‐QD‐NB and that the higher ratio of reduced NB over oxidized NB resulting from the different reducing environment of the cells can lead to brighter QD signals. Apt‐QD‐NBs are expected to be used as optical labels that can monitor intracellular metabolic pathways at the single‐cell level, because the use of Apt‐QD‐NBs to investigate drug effectiveness and cellular redox conditions offers exciting opportunities for drug screening. [ABSTRACT FROM AUTHOR]

Determination of the adipogenic potential and behavior of adipose-derived mesenchymal stem/stromal cells (ASCs) is particularly relevant for their potential clinical application in regenerative medicine, especially when regeneration is supported by biomaterials or scaffolds. Scaffolds need to be able to induce tissue repair and limit undesired adipogenic differentiation. Depending on the scaffold employed, determination of cell behavior may be hindered by material interference with staining, which will limit either cells identification or dye quantification. Collagen is a promising biomaterial in regenerative medicine, however, histological analysis of cells cultured on collagen-based scaffolds is challenging. Here we describe a new histological method based on iron hematoxylin combined with Oil red O (ORO) staining, for the determination of the adipogenic differentiation of ASCs cultivated on a collagen-based 2D scaffold. ASCs were seeded on collagen films or plastic, differentiated into adipocytes for 14 days, and then stained with either ORO or iron hematoxylin and ORO combined. The collagen films avidly absorbed the ORO dye; conventional staining and quantification by dye extraction failed to discriminate between differentiated and undifferentiated cells on the films. On the contrary, the iron hematoxylin-ORO combination provided a quantitative and more reliable determination of adipocytes based on single cell count. This method is particularly recommended for determining the adipogenic differentiation potential of ASCs and other cell types grown on highly absorptive materials that need to be validated for their potential use in bioengineering and regenerative medicine. [ABSTRACT FROM AUTHOR]

In vivo detection of cellular senescence is accomplished by using mesoporous silica nanoparticles loaded with the NIR‐FDA approved Nile blue (NB) dye and capped with a galactohexasaccharide (S3). NB emission at 672 nm is highly quenched inside S3, yet a remarkable emission enhancement is observed upon cap hydrolysis in the presence of β‐galactosidase and dye release. The efficacy of the probe to detect cellular senescence is tested in vitro in melanoma SK‐Mel‐103 and breast cancer 4T1 cells and in vivo in palbociclib‐treated BALB/cByJ mice bearing breast cancer tumor. [ABSTRACT FROM AUTHOR]

Cyclooxygenase-2 (COX-2) has been used as an excellent traceable biomarker, and exists maximally in Golgi apparatus (Cancer cells). Celecoxib (CCB) is a selective inhibitor for COX-2, and has been used as one of non-steroidal anti-inflammatory drug. Herein we report the conjugation of nile blue (NB) with CCB via a six-carbon linkage to form a fluorescence probe NB-C6-CCB for the detection of COX-2. NB-C6-CCB displays strong fluorescence with the emission peak centered at near-infrared wavelength (700 nm) in tumor cells or tumor tissues with high expression of COX-2. Importantly, NB-C6-CCB can discriminate cancer cells (MCF-7) fluorescence intensity from normal ones (COS-7) in the co-culture medium under confocal microscope. Subcellular localization of the NB-C6-CCB preferentially points to the Golgi apparatus and increases the fluorescent intensity. The competitive analysis (with CCB) and Native-PAGE analysis confirmed that NB-C6-CCB shows selective binding affinity towards COX-2 enzyme. Competitive analysis with CCB (flow cytometry assay) revealed the fluorescence intensity fluctuation due to pretreatment of CCB with different concentrations, indicating that the NB-C6-CCB is a precise or sensitive probe for the COX-2. Tumor tissue (depth: 500 µm), organs and mice imaging tests show excellent near-infrared visualization, specific localization and identification of tumors. [ABSTRACT FROM AUTHOR]

Thiophenols as high toxic environmental pollutants are poisonous for animals and aquatic organisms. Therefore, it is indispensable to monitor thiophenols in the environment. Herein, a novel near-infrared fluorescent probe was developed for the detection of thiophenols, which was easily prepared by one-step coupling of 2,4-dinitrobenzenesulfonyl chloride with Nile blue. The probe showed a significant near infrared (∼675 nm) fluorescence "turn-on" response to thiophenols with some good features including chromogenic reaction, high sensitivity and selectivity, fast response, near-infrared emission along with low detection limit (1.8 nM). The probe was employed to rapidly and visually determine thiophenols in several industrial wastewaters with good recoveries (90–110%). Moreover, this probe has been demonstrated good capability for imaging thiophenol in HeLa cells. Image 1 • A chromogenic and near-infrared fluorescence "turn-on" probe for specific detection of ArSH. • Low LOD (1.8 nM) and high selectivity for ArSH were achieved. • The probe can determine ArSH in industrial wastewater with good recovery. • The probe realized near-infrared fluorescence imaging of thiophenol in HeLa cells. [ABSTRACT FROM AUTHOR]

Ophthalmic delivery via iontophoresis is currently achieved by placing an electrode on the cornea with a counter electrode on the ear or forehead. Here we test the feasibility of placing both electrodes diametrically opposite on a contact lens to create field gradients to transport ionic drugs into the cornea. Commercial lenses loaded with nile blue and fluorescein as hydrophobic and hydrophilic drug analogs, respectively were placed on cadaver rabbit eyes. Electric field gradients were created by placing cathode and anode on the lens diametrically opposite to each other. The incorporation of an electric field (0.125 m–0.250 mA), showed an increased uptake of nile blue and the quantity was a function of the duration of the electric field and the amount of applied current. Similar increases in flux were observed for fluorescein. Confocal fluorescence imaging also shows increased penetration of the dyes in presence of the field. An equivalent circuit model suggests that the field gradients are much stronger in the direction perpendicular to the cornea, which results is minimal short circuiting of current through the tear film. The incorporation of an electric field into a lens could be a less invasive and more effective approach to achieve ophthalmic drug delivery via iontophoresis. [ABSTRACT FROM AUTHOR]

Azo dyes and herbicides are significant environmental contaminants which are characterized by the presence of one or more azo bonds (−N=N−) and aromatic species in their structure. The aim of present work is to use inexpensive and environmentally friendly nanocomposite as an adsorbent. Double-oxidized graphene oxide (GO) sheets are coated by polydopamine to adsorb the studied pollutants Nile blue (NB) and Paraquat (PQ) from wastewater. Characterizations of the synthesized GO coated with polydopamine were investigated by several techniques such as FT-IR, FE-SEM, XRD, adsorption isotherm. The effect of solution initial pH, initial concentration, and contact time was investigated. Results indicate that adsorption capacity in ambient temperature could reach 131.58, 101.01 mg/g for Nile blue and Paraquat, respectively. The efficiency of Langmuir isotherm model for these pollutants was acquired from the equilibrium adsorption data. Indeed, based on the experimental results, the possible adsorption mechanism was also suggested. [ABSTRACT FROM AUTHOR]

We used UV-vis absorption spectroscopy, fluorescence spectrophotometry and molecular docking calculations to investigate intermolecular interaction between the cationic dye, Nile blue (NB), and synthetic polynucleotides, poly(A-T), poly(G-C) and calf thymus DNA (Ct-DNA) at physiological pH. Strong hypsochromic absorbance and fluorescence quenching were observed that showed strong binding of NB to these polynucleotides and DNA. The binding affinity values derived from maximum absorption of the spectra of NB bound to various polynucleotides and Ct-DNA concentrations suggests that NB exhibits greater binding affinity to poly(G-C) than to poly(A-T). The thermodynamic parameters suggested that hydrogen bonds and van der Waals forces might play a major role in the binding of NB to DNA. The molecular docking results suggested that NB was an intercalator of the stacked base pairs of Ct-DNA. [ABSTRACT FROM AUTHOR]

The redox dye Nile blue has been adsorbed and electrochemically polymerised at a roughened gold electrode. The resulting modified electrodes were subjected to Raman spectroelectrochemical study with 785 nm laser line excitation. For both types of electrodes, well-expressed and rich in features Raman spectra were obtained. The spectra are closely related to those of another oxazine type redox dye Meldola blue. At solution pH 7.0, the overall intensity of the Raman spectra for both types of modified electrodes appears higher than in a pH 1.0 solution. Probably, this is caused by different light absorbance properties of this dye in two solutions. In a pH-neutral solution, the dye possess light absorbance in the red range of the visible spectrum, thus, resonance enhancement is possible. The intensity of the Raman spectra also increases by the shift of the electrode potential to higher positive values. This effect could be understood taking into account an intensifying colouration of the dye at a stepwise increase of the electrode potential due to a continuous growth of the content of oxidised forms within the electrode-bound layer. [ABSTRACT FROM AUTHOR]

• The novel and dual responsive fluorescent probe NapL is sensitive for Cu2+ and pH. • The probe NapL has been successfully used for the detection of Cu2+ in MCF-7 breast cancer cells under neutral conditions with low toxicity. • The probe NapL has been successfully used to make convenient and low-cost pH test strip for detecting pH range (7.4–2.1). A dual responsive and "turn-on" fluorescent probe NapL with large Stokes shift (115 nm) and large fluorescence emission (585 nm) was designed, synthesized and investigated. NapL has high selective and suitable sensitive (LOD = 82.6 nM) towards Cu2+ over a wide pH range (7.4–12.1) through a fluorescence "turn-on" mechanism and with rapid response to Cu2+ (30 s) in complex environments. Furthermore, NapL is sensitive toward pH changes within range (7.4–2.1) with obvious "turn - on" effect (about 37- fold). The sensitive detection characteristics of Cu2+ can be ascribed to the coordination performance of N and O atoms to Cu2+, whereas pH responsiveness is ascribed to the protonation of imino group. NapL has been made into convenient and low-cost pH test strip for detecting pH range (7.4–2.1), and it has also been successfully used for the detection of Cu2+ in MCF-7 breast cancer cells under neutral conditions. [ABSTRACT FROM AUTHOR]

Background: Synthetic dyes are serious pollutants and wide ranges of methods have been employed for their removal from aquatic systems. We studied the adsorption of "Nile blue A" (NBA), an anionic dye, from aqueous solution by oxidized multi-walled carbon nanotubes (MWCNTs). Methods: Scanning electron microscope and Fourier transform infrared spectroscopy were used to characterize function groups produced at MWCNTs surface. Kinetics and adsorption isotherms of NBA, the effect of temperature, pH, contact time and initial dosage of nanotubes on the adsorption capacity were also assessed. The experimental data were analyzed by Langmuir and Freundlich models. Results: Most of the dye was removed in the first 5 min and best adsorption percentage was at pH 7.0. The equilibrium reached at 45 min. The experimental data were analyzed by Langmuir and Freundlich models and the results fitted well with the Freundlich model. The adsorption kinetic data were analyzed using first-order and the pseudo-second order model and the adsorption kinetic data of NBA dye onto MWCNTs fitted the pseudo-second order model. The maximum adsorption capacity was obtained as 169.49 mg g-1. Conclusion: Freundlich model suggested that the adsorption process followed heterogeneous distribution onto MWCNTs and pseudo-second model of adsorption implied that chemical processes controlled the rate-controlling step. Oxidized MWCNTs could be used as an effective adsorbent for the removal of "Nile Blue A" dye. Oxidization of MWCNTs by nitric acid, improves the efficiency of NBA removal due to increases in functional groups and total number of adsorption sites.

Targeted medicine uses the distinctive features of cancer cells to find and destroy tumors. We present human epidermal growth factor receptor 2 (HER2)-targeted PLGA-chitosan nanoparticles for cancer therapy and visualization. Loading with two near-infrared (NIR) dyes provides imaging in the NIR transparency window and phototherapy triggered by 808 nm light. Nile Blue (NB) is a biocompatible solvatochromic NIR dye that serves as an imaging agent. Laser irradiation of IR-780 dye leads to a temperature rise and the generation of reactive oxygen species (ROS). Resonance energy transfer between two dyes allows visualization of tumors in a wide range of visible and IR wavelengths. The combination of two NIR dyes enables the use of nanoparticles for diagnostics only or theranostics. Modification of poly(lactic-co-glycolic acid) (PLGA)-chitosan nanoparticles with trastuzumab provides an efficient nanoparticle uptake by tumor cells and promotes more than sixfold specificity towards HER2-positive cells, leading to a synergistic anticancer effect. We demonstrate optical imaging of the HER2-positive mouse mammary tumor and tumor-specific accumulation of PLGA-IR-780-NB nanoparticles in vivo after intravenous administration. We managed to achieve almost complete suppression of the proliferative activity of cells in vitro by irradiation with an 808 nm laser with a power of 0.27 W for 1 min at a concentration at which nanoparticles are nontoxic to cells in the dark.