Malachite Green Derivative Research Articles

Esterase-Activated, pH-Responsive, and Genetically Targetable Nano-Prodrug for Cancer Cell Photo-Ablation.

Activatable prodrugs have drawn considerable attention for cancer cell ablation owing to their high specificity in drug delivery systems. However, phototheranostic prodrugs with dual organelle-targeting and synergistic effects are still rare due to low intelligence of their structures. Besides, the cell membrane, exocytosis, and diffusional hindrance by the extracellular matrix reduce drug uptake. Moreover, the up-regulation of heat shock protein and short singlet-oxygen lifetime in cancer cells hamper photo-ablation efficacy, especially in the mono-therapeutic model. To overcome those obstacles,we prepare an esterase-activated DM nano-prodrug, which is conjugated by diiodine-substituted fluorogenic malachite green derivative (MG-2I) and phototherapeutic agent DPP-OH via hydrolyzable ester linkage, having pH-responsiveness and genetically targetable activity for dual organelles-targeting to optimize photo-ablation efficacy. The DM nanoparticles (NPs) present improved pH-responsive photothermal/photodynamic property by the protonation of diethylaminophenyl units in acidic environment. More importantly, the MG-2I and DPP-OH moieties can be released from DM nano-prodrug through overexpressed esterase; then specifically target lysosomes and mitochondria in CT-26 Mito-FAP cells. Hence, near-infrared DM NPs can trigger parallel damage in dual-organelles with strong fluorescence and effective phototoxicity, thus inducing serious mitochondrial dysfunction and apoptotic death, showing excellent photo-ablation effect based on esterase-activated, pH-responsive, and genetically targetable activities.

Photoinduced adsorption of oligonucleotides on polyvinyl chloride films containing malachite green derivative.

DNA adsorption on the micrometer scale in a simple and cost-effective manner has received considerable interest. We prepared a film by casting an organic solvent containing polyvinyl chloride and a malachite green derivative, which can be photoionized to afford a cationic moiety for interaction with DNA. In this article, we report photoinduced oligonucleotide adsorption on a film that offers spatial and temporal control over oligonucleotide adsorption. Fluorescence microscopy was used to observe the oligonucleotide adsorption. Oligonucleotides of various sequences and lengths were also examined. UV irradiation using a photomask having 100 μm-diameter holes promoted the oligonucleotide adsorption on the film, whereas there was hardly any oligonucleotide adsorbed on the non-irradiated area. We found that the nucleobase contributed to the adsorption and part of the anchor in the oligonucleotide chain was responsible for the adsorption on the film.

Near‐Infrared and Dual Emissions of Diphenylamino Group‐Substituted Malachite Green Derivatives

AbstractNovel triarylmethanols and triarylmethyl cations with diphenylamino groups were designed and synthesized. The triarylmethyl cations exhibited near‐infrared (NIR) emission in toluene solution, solid film state, and polystyrene (PS) film. The emission intensities of the triarylmethyl cations were strongest in the PS film. The relative quantum yield of the PS film increased as the number of diphenylamino groups increased. In addition, triarylmethanols exhibit dual emission in their aggregated state owing to the intermolecular interactions between triphenyl amine moieties and/or hydroxy groups. These findings are interesting because NIR and dual emissions are not observed in the dimethylamino group‐substituted triarylmethyl cation, which is referred to as the “malachite green,” and the corresponding triarylmethanol, respectively.

PH-triggered solubility and cytotoxicity changes of malachite green derivatives incorporated in liposomes for killing cancer cells.

Three different malachite green leuco derivatives (MG-Xs) are incorporated in liposomes. In all three cases, a substituent (X) is covalently linked to the central carbon atom, abbreviated as MG-OH, MG-OCH3, and MG-CN. The three MG-X compounds are solubilized separately in liposome membranes and become cationic (MG+) and water soluble under acidic conditions. MG+ is consequently released from the liposome to the aqueous exterior. Their release behavior corresponds to their ionization ability: MG-OH > MG-OCH3 > MG-CN. The cellular uptake of the liposomes, the cytotoxic effect, and the location of MG+ in cancer cells are investigated using murine cells derived from colon cancer (Colon 26 cells) and human embryonic kidney cells (HEK 293 cells). The toxic effect on cancer cells is correlated to the ionization ability of MG-Xs. The liposomes effectively deliver MG+via the endocytic pathway, resulting in the cytotoxicity of liposomes containing MG-OH which is higher than that of free MG-OH and MG+. The difference in the phospholipids constituting the liposome membranes barely had an effect on the ionization ratio and the cytotoxicity of MG-OH. Confocal fluorescence microscopic observations revealed that MG+ is ultimately transported into the nuclei after being released in acidic cellular compartments.

Endosomal escape by photo-activated fusion of liposomes containing a malachite green derivative: a novel class of photoresponsive liposomes for drug delivery vehicles.

We conducted photo-activated delivery of drugs based on the fusion of liposomes with endocytic membranes, thus allowing the direct release of encapsulated drugs inside the cytoplasm. As described in our earlier works, liposomes can be photoresponsive and fusogenic following the incorporation of a malachite green derivative carrying a long alkyl chain (MGL) into the lipid membrane. We prepared MGL liposomes using 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine and encapsulated doxorubicin (DOX). Though the shape of MGL liposomes became elliptical after encapsulating DOX, UV irradiation did not enhance DOX leakage from MGL liposomes. We demonstrated the cellular uptake of MGL liposomes into murine cells derived from colon cancer (Colon 26 cells) using flow cytometry, and we found that the uptake was governed by a clathrin-dependent endocytosis pathway. Confocal fluorescence microscopic observations of Colon 26 cells treated with MGL liposomes encapsulating DOX revealed that DOX was localized in endosomes under dark conditions, while DOX was observed in the cytosol and nucleus after UV irradiation. The viability of Colon 26 cells treated with MGL liposomes encapsulating DOX was reduced by UV irradiation, indicating photo-induced enhancement of anti-cancer efficacy.

Self-Reporting Chemically Induced Protein Proximity System Based on a Malachite Green Derivative and the L5** Fluorogen Activating Protein.

A unique chemically induced proximity method is engineered based on mutant antibody VL domain using a fluorogenic malachite green derivative as the inducer, which gives fluorescent signals upon VL domain dimerization while simultaneously inducing downstream biological effects.

Irradiation-induced fusion between giant vesicles and photoresponsive large unilamellar vesicles containing malachite green derivative

Light-initiated fusion between vesicles has attracted much attention in the research community. In particular, fusion between photoresponsive and non-photoresponsive vesicles has been of much interest in the development of systems for the delivery of therapeutic agents to cells. We have performed fusion between giant vesicles (GVs) and photoresponsive smaller vesicles containing malachite green (MG) derivative, which undergoes ionization to afford a positive charge on the molecule by irradiation. The fusion proceeds as the concentration of GV lipid increases toward equimolarity with the lipid of the smaller vesicle. It is also dependent on the molar percentage of photoionized MG in the lipid of the smaller vesicle. On the other hand, the fusion is hardly affected by the anionic component of the GV. The photoinduced fusion was characterized by two methods, involving the mixing of lipid membranes and of aqueous contents. Fluorescence microscopy revealed that irradiation triggered the fusion of a single GV with the smaller vesicles containing MG.

Photoinduced DNA Solubilization in Chloroform Solution by Complexing with Photoionizable Malachite Green Derivative

Direct solubilization of DNA in organic solvents has attracted growing interest owing to its ability to improve the properties and versatility of DNA in nonaqueous systems, especially when irradiated. In this study, we demonstrate photoinduced DNA solubilization in a chloroform solution containing photoionizable malachite green leuconitrile carrying a long alkyl chain (MGL). Ultraviolet (UV) irradiation of MGL afforded a cationic surfactant, which then interacted with oppositely charged DNA. DNA solubilization in a chloroform/1-hexanol mixture suggested the formation of a DNA–ionized MGL complex. Fluorescence spectroscopy was used to obtain the evidence for the DNA–ionized MGL complex.

Malachite Green Derivatives for Dye-Sensitized Solar Cells: Optoelectronic Characterizations and Persistence on TiO2

Abstract Derivatives of malachite green, a well-known triphenylmethine dye, have been adapted for third-generation photovoltaic applications as dye-sensitized solar cells (DSSC). The solar cells were developed based on a concentrated Br3−/Br− liquid electrolyte coupled to different trifluoroacetate (TFA−), triflate (TfO−), bromide (Br−) and tetrafluoroborate (BF4−) malachite green salts as dye sensitizers and mesoporous TiO2 anatase as electron collector, and their optoelectronic properties were characterized. The adsorption patterns of such salts at the TiO2 nanoparticle surface were studied by zeta (ζ) potential measurements on colloidal suspensions under neat conditions, and compared to the desorption rates of the dyes when exposed to the DSSC electrolyte. The different affinities of the ionic pairs for the oxide surface and the bulk were found crucial for the stability of the self-assembled monolayer of carboxylic acid-anchored chromophores at the surface, and for the photoconversion efficiency associated therewith. This study aimed at depicting the behavior of the ionic pairs at the surface and gave insights for their physical and chemical stabilization in the DSSC environment.

A prototype reversible polymersome-stabilized H2S photoejector operating under pseudophysiological conditions.

Persistent self-assembled polymersome capsules are shown to solubilise and stabilize a new hydrosulfide-containing (), as well as hydroxylated (), malachite green derivatives in their leuco-forms in aqueous buffer solution. Photoirradiation resulted in reversible hydroxide release/hydrogen sulfide generation. Notably, the efficient augmentation of H2S concentration to physiologically-relevant levels is shown.

Malachite Green Derivative–Functionalized Single Nanochannel: Light‐and‐pH Dual‐Driven Ionic Gating (Adv. Mater. 46/2012)

Malachite Green Derivative–Functionalized Single Nanochannel: Light‐and‐pH Dual‐Driven Ionic Gating (Adv. Mater. 46/2012)

Malachite Green Derivative–Functionalized Single Nanochannel: Light‐and‐pH Dual‐Driven Ionic Gating

A highly efficient and perfectly reversible ionic gate that can be activated by pH or UV light is demonstrated. Switching between the OFF state and the ON state is mainly dependent on the surface charge transition brought about by a malachite green derivative attached to the interior surface of an ion track-etched conical nanochannel, which makes it suitable for confined spaces. Applications in electronics, actuators, and biosensors can be foreseen.

Malachite Green Derivatives for Two‐Photon RNA Detection

The design, preparation and characterisation of a library of malachite green (MG) derivatives for two-photon RNA labelling is described. Some of these MG derivatives exhibit an increased affinity for an MG-aptamer, as well as improved two-photon sensitivity when compared to the classical malachite green chloride. The underlying mechanisms and potential benefits for in vivo RNA visualisation are discussed.

UV-Responsive Polymeric Superamphiphile Based on a Complex of Malachite Green Derivative and a Double Hydrophilic Block Copolymer

We have prepared a UV-responsive polymeric superamphiphile, formed by a malachite green derivative and the double hydrophilic block copolymer methoxy-poly(ethylene glycol)(114)-block-poly(l-lysine hydrochloride)(200) (PEG-b-PLKC) on the basis of electrostatic interactions. The malachite green derivative undergoes photo-ionization upon UV irradiation, which makes it more hydrophilic, resulting in changes in the self-assembly behavior of the polymeric superamphiphile. For this reason, the polymeric superamphiphile originally self-assembles to form sheetlike aggregates, which disassemble after UV irradiation because of the increased solubility of the malachite green derivative. By use of Nile red as a probe, the polarity of the polymeric superamphiphile solution is confirmed to be increased after UV irradiation by fluorescence spectra, which also explains the disassembly of the polymeric superamphiphile.

光によるベシクルの形態変化：マラカイトグリーン誘導体の光イオン化反応がもたらすベシクル膜の融合、出芽、溶解

光によるベシクルの形態変化：マラカイトグリーン誘導体の光イオン化反応がもたらすベシクル膜の融合、出芽、溶解

Morphological Changes in Vesicles and Release of an Encapsulated Compound Triggered by a Photoresponsive Malachite Green Leuconitrile Derivative

Photoinduced morphological changes in phosphatidylcholine vesicles are triggered by a Malachite Green leuconitrile derivative dissolved in the lipidic membrane, and are observed at Malachite Green derivative/lipid ratios <5 mol %. This Malachite Green derivative is a photoresponsive compound that undergoes ionization to afford a positive charge on the molecule by UV irradiation. The Malachite Green derivative exhibits amphiphilicity when ionized photochemically, whereas it behaves as a lipophilic compound under dark conditions. Cryo-transmission electron microscopy was used to determine vesicle morphology. The effects of the Malachite Green derivative on vesicles were studied by dynamic light scattering and fluorescence resonance energy transfer. Irradiation of vesicles containing the Malachite Green derivative induces nonspherical vesicle morphology, fusion of vesicles, and membrane solubilization, depending on conditions. Furthermore, irradiation of the Malachite Green derivative induces the release of a vesicle-encapsulated compound.

Light-Controlled Single-Walled Carbon Nanotube Dispersions in Aqueous Solution

We have succeeded in dispersing single-walled carbon nanotubes (SWNTs) into an aqueous solution of poly(ethylene glycol)-terminated malachite green derivative (PEG-MG) through simple sonication. It was found that UV exposure caused reaggregation of these predispersed SWNTs in the same aqueous medium, as adsorbed PEG-MG photochromic chains could be effectively photocleavaged from the nanotube surface. The observed light-controlled dispersion and reaggragation of SWNTs in the aqueous solution should facilitate the development of SWNT dispersions with a controllable dispersity for potential applications.

Self‐Assembled Monolayers of a Malachite Green Derivative: Surfaces with pH‐ and UV‐Responsive Wetting Properties

Surfaces that respond to pH and UV stimuli are fabricated from self-assembled monolayers (SAMs) of a malachite green derivative on a rough surface (see figure). The wetting properties of the SAMs exhibit an uncommon response to pH and UV illumination, and range from superhydrophobicity to superhydrophilicity.

Photochemical micelle control by long‐alkyl‐chain Malachite Green

AbstractWe have designed a Malachite Green leuconitrile carrying a long‐alkyl‐chain which controls micelle formation photochemically. The Malachite Green derivative, when ionized photochemically, exhibits some hydrophilicity by its triphenylmethyl cation and some hydrophobicity by its long alkyl chain. The behavior of the photoresponsive Malachite Green surfactant was studied in mixed micelle solutions containing cetyltrimethylammonium chloride (CTAC) and a small quantity of the Malachite Green. We found that UV irradiation drastically decreased the critical micelle concentration (cmc) of the mixed micelle solutions and that the Malachite Green derivative realized photoinduced uptake of oily substances based on its photogenerated amphiphilicity. The mechanism of the photoinduced enhancement of solubilizing oily substances is discussed at the viewpoint of the microscopic location of the Malachite Green surfactant in the micelle. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Reversible Self-Organization of a UV-Responsive PEG-Terminated Malachite Green Derivative: Vesicle Formation and Photoinduced Disassembly

This paper describes the assembly and disassembly of vesicles formed by a UV-responsive poly(ethylene glycol) terminated malachite green derivative. The UV-responsive amphiphile with both a hydrophobic malachite green group and a hydrophilic PEG group can self-organize into vesicles in water before UV irradiation. However, upon UV irradiation, the photochromic moiety can be ionized to its corresponding cation, leading to the disassembly of these vesicles. In addition, the cation can thermally recover its electrically neutral form, and the disassembled species can form vesicles reversibly on the basis of a thermal reverse reaction. The reverse reaction is temperature-controlled and can be speeded up by thermal treatment. By using various characterization techniques, e.g., transmission electron microscopy, dynamic light scattering, UV-visible spectroscopy, and NMR spectroscopy, we have confirmed that the vesicle structures can be formed, disassembled, and recovered by the above-mentioned treatments. It is anticipated greatly that this line of research may provide new insights into the mechanism behind stimuli-responsive formation and rupture of molecular assemblies, facilitating the design and synthesis of new surface active molecules for the fabrication of stimuli-responsive materials with designed functions.