Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 51
Filter
Add more filters










Publication year range
1.
Carbohydr Polym ; 269: 118242, 2021 Oct 01.
Article in English | MEDLINE | ID: mdl-34294284

ABSTRACT

To promote bactericidal activity, improve photostability and safety, novel antibacterial nanoparticle system based on photodynamic action (PDA) was prepared here through conjugation of photosensitizer hematoporphyrin (HP) onto carboxymethyl chitosan (CMCS) via amide linkage and followed by ultrasonic treatment. The system was stable in PBS (pH 7.4) and could effectively inhibit the photodegradation of conjugated HP because of aggregation-caused quenching effect. ROS produced by the conjugated HP under light exposure could change the structure of nanoparticles by oxidizing the CMCS skeleton and thereby significantly promote the photodynamic activity of HP and its photodynamic activity after 6 h was higher than that of HP·2HCl under the same conditions. Antibacterial experiments showed that CMCS-HP nanoparticles had excellent photodynamic antibacterial activity, and the bacterial inhibition rates after 60 min of light exposure were greater than 97%. Safety evaluation exhibited that the nanoparticles were safe to mammalian cells, showing great potential for antibacterial therapy.


Subject(s)
Anti-Bacterial Agents/pharmacology , Chitosan/analogs & derivatives , Hematoporphyrins/pharmacology , Nanoparticles/chemistry , Photosensitizing Agents/pharmacology , Animals , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/radiation effects , Anti-Bacterial Agents/toxicity , Chitosan/chemical synthesis , Chitosan/pharmacology , Chitosan/radiation effects , Chitosan/toxicity , Escherichia coli/drug effects , Hematoporphyrins/chemical synthesis , Hematoporphyrins/radiation effects , Hematoporphyrins/toxicity , Light , Mice , Microbial Sensitivity Tests , NIH 3T3 Cells , Nanoparticles/radiation effects , Nanoparticles/toxicity , Particle Size , Photosensitizing Agents/chemical synthesis , Photosensitizing Agents/radiation effects , Photosensitizing Agents/toxicity , Reactive Oxygen Species/metabolism , Staphylococcus aureus , Surface-Active Agents/chemical synthesis , Surface-Active Agents/pharmacology , Surface-Active Agents/radiation effects , Surface-Active Agents/toxicity
2.
ACS Appl Mater Interfaces ; 12(20): 22552-22559, 2020 May 20.
Article in English | MEDLINE | ID: mdl-32345006

ABSTRACT

Organic materials that show substantial reactivity under visible light have received considerable attention due to their wide applications in chemical and biological systems. Hemicyanine pigments possess a strong intramolecular donor-acceptor structure and thereby display intense absorption in the visible spectral region. However, most excitons are consumed via the twisted intramolecular charge-transfer (TICT) process, making hemicyanines generally inert to light. Herein, we describe the development of an amphiphilic hemicyanine dye whose aggregation could be easily regulated using salt or counterions. More importantly, its intrinsic photoreactivity was successfully induced by steric restriction and cofacial arrangement within the H-aggregate, thus creating an effective photobactericide. This strategy could be extended to the development of photocatalysts for photosynthesis and a photosensitizer for photodynamic therapy.


Subject(s)
Aniline Compounds/pharmacology , Anti-Bacterial Agents/pharmacology , Coloring Agents/pharmacology , Stilbenes/pharmacology , Aniline Compounds/radiation effects , Anti-Bacterial Agents/radiation effects , Coloring Agents/radiation effects , Escherichia coli/drug effects , Hydroxyl Radical/metabolism , Light , Microbial Sensitivity Tests , Stilbenes/radiation effects , Surface-Active Agents/pharmacology , Surface-Active Agents/radiation effects
3.
Nat Methods ; 16(5): 417-420, 2019 05.
Article in English | MEDLINE | ID: mdl-30988469

ABSTRACT

We report the identification of a photocleavable anionic surfactant, 4-hexylphenylazosulfonate (Azo), which can be rapidly degraded by ultraviolet irradiation, for top-down proteomics. Azo can effectively solubilize proteins with performance comparable to that of sodium dodecyl sulfate (SDS) and is compatible with mass spectrometry. Azo-aided top-down proteomics enables the solubilization of membrane proteins for comprehensive characterization of post-translational modifications. Moreover, Azo is simple to synthesize and can be used as a general SDS replacement in SDS-polyacrylamide gel electrophoresis.


Subject(s)
Azo Compounds/chemistry , Electrophoresis, Polyacrylamide Gel/methods , Proteomics/methods , Sodium Dodecyl Sulfate/chemistry , Surface-Active Agents/chemistry , Azo Compounds/radiation effects , Hydrophobic and Hydrophilic Interactions , Mass Spectrometry , Membrane Proteins/analysis , Photolysis , Sodium Dodecyl Sulfate/radiation effects , Solubility , Surface-Active Agents/radiation effects , Ultraviolet Rays
4.
Methods Mol Biol ; 1943: 101-122, 2019.
Article in English | MEDLINE | ID: mdl-30838612

ABSTRACT

Polymerized micelles obtained by photopolymerization of diacetylenic surfactants and which are forming polydiacetylenic systems (PDAs) have recently gained interest as stabilized monodisperse systems showing potential for the delivery of hydrophobic drugs as well as of larger biomolecules such as nucleic acids. Introduction of pH-sensitive histidine groups at the surface of the micellar PDA systems allows for efficient delivery of siRNA resulting in specific gene silencing through RNA interference. Here, we describe the detailed experimental procedure for the reproducible preparation of these photopolymerized PDA micelles. We provide physicochemical characterization of these nanomaterials by dynamic light scattering, transmission electron microscopy, and diffusion ordered spectroscopy. Moreover, we describe standardized biological tests to evaluate the silencing efficiency by the use of a cell line constitutively expressing the luciferase reporter gene.


Subject(s)
Nanoparticles/chemistry , Polyacetylene Polymer/chemistry , Transfection/methods , A549 Cells , Cations/chemistry , Cations/radiation effects , Genes, Reporter/genetics , Humans , Hydrophobic and Hydrophilic Interactions , Light , Luciferases/genetics , Micelles , Polyacetylene Polymer/radiation effects , Polymerization/radiation effects , RNA Interference , RNA, Small Interfering/chemistry , RNA, Small Interfering/genetics , Surface-Active Agents/chemistry , Surface-Active Agents/radiation effects
5.
Carbohydr Polym ; 206: 309-318, 2019 Feb 15.
Article in English | MEDLINE | ID: mdl-30553327

ABSTRACT

In this paper, a novel photo-controlled drug-loaded nanomicelles were self-assembled by the amphiphile of hyaluronan-o-nitrobenzyl-stearyl chain (HA-NB-SC) with doxorubicin (DOX) encapsulated within the hydrophobic core. DOX-loaded HA-NB-SC nanomicelles are ∼139 nm in diameter. CD44-overexpressed HeLa cells can easily take up HA-NB-SC micelles through recognition of HA moiety. DOX-loaded HA-NB-SC nanomicelles could be disassembled upon UV light (365 nm) and consequently, release DOX at desired pathological sites. Furtherly, nitrosobenzaldehyde derivative, photo-induced products of HA-NB-SC and DOX could inhibit the proliferation of HeLa cells together. This strategy may shed some light on delivery of hydrophobic anti-cancer drugs in a controlled manner.


Subject(s)
Antineoplastic Agents/pharmacology , Doxorubicin/pharmacology , Drug Carriers/chemistry , Hyaluronic Acid/analogs & derivatives , Nanostructures/chemistry , Surface-Active Agents/chemistry , Antineoplastic Agents/chemistry , Doxorubicin/chemistry , Drug Carriers/chemical synthesis , Drug Carriers/radiation effects , Drug Carriers/toxicity , Drug Liberation , HEK293 Cells , HeLa Cells , Humans , Hyaluronic Acid/chemical synthesis , Hyaluronic Acid/radiation effects , Hyaluronic Acid/toxicity , Light , Micelles , Nanostructures/radiation effects , Nanostructures/toxicity , Nitrobenzoates/chemical synthesis , Nitrobenzoates/chemistry , Nitrobenzoates/radiation effects , Nitrobenzoates/toxicity , Particle Size , Surface-Active Agents/chemical synthesis , Surface-Active Agents/radiation effects , Surface-Active Agents/toxicity
6.
Chemphyschem ; 19(5): 643-650, 2018 Mar 05.
Article in English | MEDLINE | ID: mdl-29205715

ABSTRACT

The self-assembly of tyrosyl bolaamphiphiles is exploited to create a colloidal protein-like host matrix, upon which sacrificial electron-donor molecules associate to create a photosystem II (PSII) mimetic electron-relay system. This system harnesses the tyrosine phenol groups abundant on the surface of the assemblies to mediate photoinduced intermolecular electron transfer. Compared with the l-tyrosine molecules, the tyrosyl bolaamphiphile assembly facilitates electron transfer from the sacrificial electron donor to the oxidized photosensitizer. The enhanced electron relay is likely to be driven by the host function of the assembly associated with the sacrificial electron donor and by the suppression of the oxidative cross-linking of phenoxyl radicals. The tyrosyl bolaamphiphile assembly is advantageous in the construction of a PSII mimetic system with a protein-like nature and displaying biochemical functions.


Subject(s)
Biomimetic Materials/radiation effects , Surface-Active Agents/radiation effects , Tyrosine/analogs & derivatives , Tyrosine/radiation effects , Biomimetic Materials/chemistry , Cadaverine/analogs & derivatives , Cadaverine/chemistry , Cadaverine/radiation effects , Cobalt/chemistry , Coordination Complexes , Electrons , Fluorescence , Fluorescent Dyes/chemistry , Fluorescent Dyes/radiation effects , Molecular Structure , Organometallic Compounds/chemistry , Organometallic Compounds/radiation effects , Oxidation-Reduction , Photosensitizing Agents/chemistry , Photosensitizing Agents/radiation effects , Photosystem II Protein Complex/chemistry , Surface-Active Agents/chemistry , Tyrosine/chemistry
7.
Chem Commun (Camb) ; 54(3): 275-278, 2018 Jan 02.
Article in English | MEDLINE | ID: mdl-29231935

ABSTRACT

Two novel bola-amphiphilic oligo-p-(phenyleneethynylene) (OPE) dicarboxylates have been synthesized having non-polar and mixed-polar side chains. This led to gelation in both with vesicular morphology. Upon in situ loading of a suitable dye and redox-active molecule, pure white light emitting and charge transfer (CT)-gels, respectively, were realized.


Subject(s)
Alkynes/chemistry , Benzene Derivatives/chemistry , Luminescent Agents/chemistry , Surface-Active Agents/chemistry , Alkynes/chemical synthesis , Alkynes/radiation effects , Azo Compounds/chemistry , Benzene Derivatives/chemical synthesis , Benzene Derivatives/radiation effects , Gels , Light , Luminescent Agents/chemical synthesis , Luminescent Agents/radiation effects , Nitriles/chemistry , Surface-Active Agents/chemical synthesis , Surface-Active Agents/radiation effects
8.
Biomacromolecules ; 17(6): 1959-68, 2016 06 13.
Article in English | MEDLINE | ID: mdl-27030485

ABSTRACT

Light-induced DNA compaction as part of nonviral gene delivery was investigated intensively in the past years, although the bridging between the artificial light switchable compacting agents and biocompatible light insensitive compacting agents was not achieved until now. In this paper, we report on light-induced compaction and decompaction of DNA molecules in the presence of a new type of agent, a multivalent cationic peptidomimetic molecule containing a photosensitive Azo-group as a branch (Azo-PM). Azo-PM is synthesized using a solid-phase procedure during which an azobenzene unit is attached as a side chain to an oligo(amidoamine) backbone. We show that within a certain range of concentrations and under illumination with light of appropriate wavelengths, these cationic molecules induce reversible DNA compaction/decompaction by photoisomerization of the incorporated azobenzene unit between a hydrophobic trans- and a hydrophilic cis-conformation, as characterized by dynamic light scattering and AFM measurements. In contrast to other molecular species used for invasive DNA compaction, such as widely used azobenzene containing cationic surfactant (Azo-TAB, C4-Azo-OCX-TMAB), the presented peptidomimetic agent appears to lead to different complexation/compaction mechanisms. An investigation of Azo-PM in close proximity to a DNA segment by means of a molecular dynamics simulation sustains a picture in which Azo-PM acts as a multivalent counterion, with its rather large cationic oligo(amidoamine) backbone dominating the interaction with the double helix, fine-tuned or assisted by the presence and isomerization state of the Azo-moiety. However, due to its peptidomimetic backbone, Azo-PM should be far less toxic than photosensitive surfactants and might represent a starting point for a conscious design of photoswitchable, biocompatible vectors for gene delivery.


Subject(s)
Azo Compounds/chemistry , DNA/chemistry , Light , Peptidomimetics/chemistry , Surface-Active Agents/chemistry , Azo Compounds/radiation effects , Chemical Precipitation , DNA/genetics , DNA/radiation effects , Dynamic Light Scattering , Gene Transfer Techniques , Hydrophobic and Hydrophilic Interactions , Molecular Dynamics Simulation , Nucleic Acid Conformation , Peptidomimetics/radiation effects , Photochemical Processes , Surface-Active Agents/radiation effects
9.
Chem Commun (Camb) ; 51(58): 11595-8, 2015 Jul 25.
Article in English | MEDLINE | ID: mdl-26095460

ABSTRACT

A series of polydiacetylene (PDA) - based micelles were prepared from diacetylenic surfactant bearing polyethylene glycol, by increasing UV-irradiation times. These polymeric lipid micelles were analyzed by physicochemical methods, electron microscopy and NMR analysis. Cellular delivery of fluorescent dye suggests that adjusting the polymerization state is vital to reach the full in vitro potential of PDA-based delivery systems.


Subject(s)
Drug Delivery Systems , Micelles , Polyethylene Glycols/chemistry , Polymers/chemistry , Polyynes/chemistry , Surface-Active Agents/chemistry , Cell Line , Cell Survival/drug effects , Fluorescent Dyes/administration & dosage , Fluorescent Dyes/chemistry , HeLa Cells , Humans , Oxazines/administration & dosage , Oxazines/chemistry , Polyacetylene Polymer , Polyethylene Glycols/radiation effects , Polymerization , Polymers/radiation effects , Polyynes/radiation effects , Surface-Active Agents/radiation effects , Ultraviolet Rays
10.
J Hazard Mater ; 282: 241-8, 2015 Jan 23.
Article in English | MEDLINE | ID: mdl-25262384

ABSTRACT

Four different oxidation process, namely direct photolysis (DP) and three advanced oxidation processes (heterogeneous photocatalysis - HP, eletrochemical oxidation - EO and photo-assisted electrochemical oxidation - PEO) were applied in the treatment of wastewater containing nonylphenol ethoxylate (NPnEO). The objective of this work was to determine which treatment would be the best option in terms of degradation of NPnEO without the subsequent generation of toxic compounds. In order to investigate the degradation of the surfactant, the processes were compared in terms of UV/Vis spectrum, mineralization (total organic carbon), reaction kinetics, energy efficiency and phytotoxicity. A solution containing NPnEO was prepared as a surrogate of the degreasing wastewater, was used in the processes. The results showed that the photo-assisted processes degrade the surfactant, producing biodegradable intermediates in the reaction. On the other hand, the electrochemical process influences the mineralization of the surfactant. The process of PEO carried out with a 250W lamp and a current density of 10mA/cm(2) showed the best results in terms of degradation, mineralization, reaction kinetics and energy consumption, in addition to not presenting phytotoxicity. Based on this information, this process can be a viable alternative for treating wastewater containing NPnEO, avoiding the contamination of water resources.


Subject(s)
Endocrine Disruptors , Ethylene Glycols , Surface-Active Agents , Ultraviolet Rays , Waste Disposal, Fluid/methods , Water Pollutants, Chemical , Carbon/analysis , Cell Survival/drug effects , Electrochemistry , Endocrine Disruptors/chemistry , Endocrine Disruptors/radiation effects , Endocrine Disruptors/toxicity , Ethylene Glycols/chemistry , Ethylene Glycols/radiation effects , Ethylene Glycols/toxicity , Lactuca/drug effects , Lactuca/genetics , Lactuca/growth & development , Mutagenicity Tests , Onions/drug effects , Onions/genetics , Onions/growth & development , Oxidation-Reduction , Photolysis , Plant Roots/drug effects , Plant Roots/genetics , Plant Roots/growth & development , Surface-Active Agents/chemistry , Surface-Active Agents/radiation effects , Surface-Active Agents/toxicity , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/radiation effects , Water Pollutants, Chemical/toxicity
11.
Carbohydr Polym ; 117: 201-210, 2015 Mar 06.
Article in English | MEDLINE | ID: mdl-25498626

ABSTRACT

In this study, we synthesized photocleavable amphiphilic block copolymers containing photodegradable linkers, 5-hydroxy-2-nitrobenzyl alcohol, as junction points between hydrophilic dextran (or maltodextrin) and hydrophobic poly(4-substituted-ɛ-caprolactone) chains, by using a combination of ring-opening polymerization and nucleophilic substitution reactions. When the polymer solutions were exposed to ultraviolet (UV) irradiation, major structural and morphological changes were observed in the particles. The copolymers were biodegradable and biocompatible, and they can self-assemble into spherical photoresponsive micelles. Fluorescence emission measurements indicated the release of Nile red, a hydrophobic dye, encapsulated by the Dex-ONB-PXCL micelles, in response to irradiation caused by the disruption of the micelles. Light-triggered bursts were observed for indomethacin (IMC)-loaded Dex-ONB-PXCL micelles during the first 5 h. The nanoparticles were associated with nonsignificant toxicity at concentrations of less than 100 µg mL(-1). The confocal microscopy and flow cytometry results showed that the uptake of DOX-loaded micelles by HeLa cells was slightly less than that of free DOX, and it was predominantly retained in the cytoplasm.


Subject(s)
Caproates/chemistry , Dextrans/chemistry , Drug Carriers/chemical synthesis , Lactones/chemistry , Micelles , Polymers/chemical synthesis , Surface-Active Agents/chemical synthesis , Benzyl Alcohols/chemistry , Doxorubicin/administration & dosage , Doxorubicin/pharmacology , Drug Carriers/radiation effects , HeLa Cells , Humans , Nitrobenzenes/chemistry , Photolysis , Polymers/radiation effects , Surface-Active Agents/radiation effects , Ultraviolet Rays
12.
Chemosphere ; 119 Suppl: S101-8, 2015 Jan.
Article in English | MEDLINE | ID: mdl-24880608

ABSTRACT

In this work the photoelectrooxidation (PEO) was applied in the treatment of a solution containing nonylphenol ethoxylate surfactant (NP4EO). The use of different lamps (125 and 250 W), current density (5 and 10 mA cm(-2)) and treatment time (0, 60, 120, 180 and 240 min) were investigated. The samples were characterized by UV/Vis, total organic carbon (TOC), gas chromatography associated to mass spectroscopy (GC/MS) and ecotoxicity. The reaction kinetics were calculated and the light flux and pH were measured. The results of analysis by UV/Vis show that there is degradation of nonylphenol ethoxylated in the treatment time of 240 min for all configurations, and the configurations that used a 250 W lamp and a current density of 10 mA cm(-2) obtained better results, with a reduction of 83% in TOC, indicating a high mineralization of the surfactant. It was further found in the GC/MS that the configurations that used the 125 W lamp promoted a smaller incident light flux on the solution, and, regardless of the applied current density, it was generated the reaction intermediate nonylphenol, more toxic than the parent compound. The opposite can be observed when a 250 W lamp was used, which produced a higher incident light flux. Based on the degradation products detected, a simplified mechanism for degradation of nonylphenol ethoxylate was proposed. Although a treatment time of 240 min with photoelectrooxidation with different configurations was not effective in the complete mineralization of the compound, a promising process was developed with the treatment using a lamp of 250 W and a current density of 10 mA cm(-2), which generated a solution with less toxicity than the original one.


Subject(s)
Ethylene Glycols/chemistry , Ethylene Glycols/radiation effects , Surface-Active Agents/chemistry , Surface-Active Agents/radiation effects , Electrochemical Techniques , Gas Chromatography-Mass Spectrometry , Hydrogen-Ion Concentration , Kinetics , Photochemical Processes , Solutions , Ultraviolet Rays , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/radiation effects , Water Purification/methods
13.
Small ; 10(15): 3119-30, 2014 Aug 13.
Article in English | MEDLINE | ID: mdl-24729486

ABSTRACT

In this study, amphiphilic Janus-type polymers were synthesized via ring-opening metathesis polymerization (ROMP), multiple vicinal diol formation, and grafting of poly(ethylene glycol) monomethyl ether (mPEG). These amphiphilic polymers formed self-assemblies, which were a mixture of micelles and multimicellar aggregates, in water. By choosing suitable Janus-type polymers and irradiating an aqueous solution of polymers using a sonicator, either small micelles or large multimicellar aggregates were obtained selectively. Hydrophobic substituents controlled the aggregation-disaggregation behavior, leading to the formation of metastable self-assemblies by sonication. The formation of self-assemblies with a uniform size was affected by ultrasonic frequency, rather than power. In vivo optical tumor imaging revealed that the large-size multimicellar aggregates persisting for a long time in blood circulation slowly accumulated in tumor tissues. In contrast, the tumor site was rapidly, clearly visualized using the small-size micelles.


Subject(s)
Fluorescent Dyes/chemical synthesis , Microscopy, Fluorescence/methods , Nanoparticles/chemistry , Neoplasms, Experimental/pathology , Sonication/methods , Cell Line, Tumor , Crystallization/methods , High-Energy Shock Waves , Humans , Nanoparticles/radiation effects , Particle Size , Polymers/chemistry , Surface-Active Agents/chemical synthesis , Surface-Active Agents/radiation effects
14.
Drug Dev Ind Pharm ; 39(9): 1457-63, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23902365

ABSTRACT

Photo-responsive monoolein (MO) cubic phase was developed by incorporating coumarin-Tween 20 conjugate in the cubic phase. 7-chlorocarbonylmethoxycoumarin was obtained from 7-hydroxycoumarin through three-step reactions with the yield of 19.8% and it was conjugated to the head group of Tween 20. The molar ratio of the coumarin derivative/Tween 20 in the conjugate was about 1/1 on ¹H NMR spectrum. The cubic phase was prepared by melting the mixture of MO/conjugate (100/0.88, w/w) and hydrating the molten mixture with 5(6)-carboxyfluorescein (CF) solution. UV irradiation (254 nm and/or 365 nm) for 3 h resulted in 1.27% to 2.69% reduction in the double bond of MO but the cubic phase was stable in terms of its integrity under the UV irradiation. The release of CF from coumarin-Tween 20 conjugate-incorporated cubic phase was somewhat suppressed by being subjected to the UV irradiation. The head groups of coumarin-Tween 20 conjugate will be cross-linked so the diffusion in the water channel will be suppressed.


Subject(s)
Anticoagulants/chemistry , Coumarins/chemistry , Drug Delivery Systems , Glycerides/chemistry , Pharmaceutical Vehicles/chemistry , Polysorbates/chemistry , Ultraviolet Rays , Anticoagulants/radiation effects , Coumarins/radiation effects , Dimerization , Drug Stability , Fluoresceins/chemistry , Fluorescent Dyes/chemistry , Glycerides/radiation effects , Hot Temperature , Hymecromone/analogs & derivatives , Hymecromone/chemical synthesis , Hymecromone/chemistry , Hymecromone/radiation effects , Kinetics , Magnetic Resonance Spectroscopy , Pharmaceutical Vehicles/radiation effects , Phase Transition , Photochemical Processes , Polysorbates/radiation effects , Solubility , Surface-Active Agents/chemistry , Surface-Active Agents/radiation effects , Umbelliferones/chemistry , Umbelliferones/radiation effects
15.
Mutagenesis ; 28(1): 7-14, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22987026

ABSTRACT

Nonylphenolpolyethoxylates (NPEOs) are non-ionic surfactants widely used for industrial and household purposes. In actual environments, NPEOs can be biodegraded, but the products are reported to be more persistent and toxic than the parent compounds. NPEOs are also exposed to sunlight and degraded. Studies on the photodegradation of NPEOs have focused mainly on chemical changes after exposure to light. Toxic changes of photodegraded products correlating to the chemical changes are not completely understood. In this study, we examined the genotoxicity of UVB-irradiated NPEOs having ethylene oxide units 15 and 70 in a human breast adenocarcinoma cell line, MCF-7, based on the phosphorylation of histone H2AX (γ-H2AX), a sensitive marker for DNA damage. We clarified that UVB irradiation drastically changed the genotoxic potential of NPEOs: NPEO(15)'s ability to generate γ-H2AX was significantly reduced, whereas non-genotoxic NPEO(70) became able to generate γ-H2AX. Flow cytometric analysis showed that the γ-H2AX generated by UVB-irradiated NPEO(70)was produced independent of cell cycle phases. In addition, its production involved the activation of ATM or DNA-PK, a general signalling pathway in response to DNA double strand breaks. High-performance liquid chromatography analysis indicated that the formation of NPEO intermediates with a short side-chain like NPEO(15) was the cause of the γ-H2AX generation. This study suggests the importance of taking the genotoxicity of photodegraded intermediates into consideration when conducting risk assessments of environmental pollutants.


Subject(s)
Histones/metabolism , Surface-Active Agents/radiation effects , Surface-Active Agents/toxicity , Ultraviolet Rays , Biomarkers/metabolism , Cell Line, Tumor , Chromatography, High Pressure Liquid , DNA Damage/drug effects , Female , Flow Cytometry , Humans , Mutagenicity Tests/methods , Phosphorylation , Reactive Oxygen Species/metabolism , Surface-Active Agents/chemistry
16.
Ultrason Sonochem ; 19(3): 435-9, 2012 May.
Article in English | MEDLINE | ID: mdl-22154732

ABSTRACT

A novel technique for anionic surfactant assisted separation and preconcentration of metal cations was developed using ultrasound induced nebulization at MHz frequency. The ions of copper, zinc, cadmium, and calcium were used as model analytes. Analysis of the aerosol using flame atomic absorption spectrometry showed enrichment factors for the metal ions studied between 5 and 8, when dilute solutions containing sodium dodecylsulfate and the metal ions were nebulized. The mechanism of metal ion enrichment was explained based on surfactant adsorption and the droplet model for aerosol droplets. It was demonstrated that further increase in the enrichment factor could be achieved by increasing the ultrasound frequency, thus producing smaller droplets.


Subject(s)
Aerosols/chemical synthesis , Metals/isolation & purification , Metals/radiation effects , Models, Chemical , Sonication/methods , Surface-Active Agents/chemistry , Surface-Active Agents/radiation effects , Aerosols/radiation effects , Anions , Computer Simulation , High-Energy Shock Waves , Metals/chemistry , Nebulizers and Vaporizers , Radiation Dosage
18.
Biomacromolecules ; 12(11): 3945-51, 2011 Nov 14.
Article in English | MEDLINE | ID: mdl-21958293

ABSTRACT

AzoTAB, a photosensitive azobenzene cationic surfactant, which phototriggers translation activity through light-regulated condensation of mRNA, is added to a translation solution containing several mRNAs, which can be selectively silenced by specific small RNAs. We find that gene silencing by small RNAs remains functional regardless of AzoTAB concentration and UV illumination. In the absence of UV, the translation of all genes present in the medium is partially to fully inhibited depending on AzoTAB concentration. In contrast, the application of a short UV stimulus (365 nm for 1.5 min) results in the selective photoactivation of genes that are not silenced by small RNA. These results show that light-regulated condensation by AzoTAB works as a sequence-independent series photoswitch added to parallel sequence-specific regulation by small RNAs.


Subject(s)
Azo Compounds/chemistry , Protein Biosynthesis , RNA, Small Interfering/chemistry , Surface-Active Agents/chemistry , Ultraviolet Rays , Azo Compounds/radiation effects , Green Fluorescent Proteins/chemistry , Green Fluorescent Proteins/genetics , Nucleic Acid Conformation , RNA Interference , RNA, Messenger , Surface-Active Agents/radiation effects
19.
Lab Chip ; 11(16): 2666-9, 2011 Aug 21.
Article in English | MEDLINE | ID: mdl-21727984

ABSTRACT

We describe a method to induce by light a reversible switch from a continuous two-phase laminar flow to a droplet generating regime, in microfluidic devices with a usual water-in-oil flow focusing geometry. It consists in adding a photosensitive surfactant to the aqueous phase to modulate using light the interfacial energy between flowing liquids and the microfluidic substrate. We show that UV irradiation induces liquid fragmentation into monodisperse water microdroplets and that many cycles of reversible and rapid switches (<2 s) between continuous laminar flows and stable droplet regimes can be realized. By spatially controlling the application of the light stimulus, we also demonstrate the first spatially resolved remote induction of droplet generation.


Subject(s)
Light , Microfluidics/methods , Surface-Active Agents/chemistry , Surface-Active Agents/radiation effects , Microfluidics/instrumentation , Molecular Structure , Oils/chemistry , Particle Size , Surface Properties , Ultraviolet Rays , Water/chemistry , Wettability
20.
Ultrason Sonochem ; 18(5): 958-62, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21317016

ABSTRACT

A metal ion (Cu(2+)) and a complex copper species, copper (II) bis-bipyridine, were used as alternate counterions in an aqueous surfactant solution of sodium dodecylbenzenesulfonate (SDBS) to investigate the dynamics of counterion interactions in an acoustic field. Sonoluminescence spectral studies showed that such counterions were able to replace sodium ions at the interface, even when the interface was rapidly oscillating under the acoustic field. Ultrasound induced nebulisation was then used to probe the interfacial profile of surfactant and bound counterions in a dynamic environment. At low bulk concentrations, the copper (II) bis-bipyridine cation was more effective at enhancing the loading of the dodecylbenzenesulfonate anion on the interface, due to its documented greater binding ability. However, at higher bulk concentrations, the movement of this cation is limited by its larger size and the smaller Cu(2+) cation is more effective in enhancing the loading of the dodecylbenzenesulfonate anion. The results show that under dynamic conditions, the surface concentrations are governed by mass transfer kinetics rather than equilibrium thermodynamics.


Subject(s)
Copper/chemistry , Copper/radiation effects , Gases/chemical synthesis , Gases/radiation effects , Sonication/methods , Surface-Active Agents/chemistry , Surface-Active Agents/radiation effects , Binding Sites/radiation effects , Ions , Radiation Dosage
SELECTION OF CITATIONS
SEARCH DETAIL
...