Photoacoustic imaging of elevated glutathione in models of lung cancer for companion diagnostic applications.

Companion diagnostics (CDx) are powerful tests that can provide physicians with crucial biomarker information that can improve treatment outcomes by matching therapies to patients. Here, we report a photoacoustic imaging-based CDx (PACDx) for the selective detection of elevated glutathione (GSH) in a lung cancer model. GSH is abundant in most cells, so we adopted a physical organic chemistry approach to precisely tune the reactivity to distinguish between normal and pathological states. To evaluate the efficacy of PACDx in vivo, we designed a blind study where photoacoustic imaging was used to identify mice bearing lung xenografts. We also employed PACDx in orthotopic lung cancer and liver metastasis models to image GSH. In addition, we designed a matching prodrug, PARx, that uses the same SNAr chemistry to release a chemotherapeutic with an integrated PA readout. Studies demonstrate that PARx can inhibit tumour growth without off-target toxicity in a lung cancer xenograft model.

Construction of self-enhanced photoelectrochemical platform for L-cysteine detection via electron donor-acceptor type coumarin 545 aggregates.

Self-enhanced electron donor-acceptor type coumarin 545 aggregates prepared via an anionic surfactant-assisted reprecipitation method provide an underlying approach for the photoelectrochemical detection of L-cysteine, which can be employed in aqueous solution without the addition of electron donors.

Polycationic Monomeric and Homodimeric Asymmetric Monomethine Cyanine Dyes with Hydroxypropyl Functionality-Strong Affinity Nucleic Acids Binders.

New analogs of the commercial asymmetric monomethine cyanine dyes thiazole orange (TO) and thiazole orange homodimer (TOTO) with hydroxypropyl functionality were synthesized and their properties in the presence of different nucleic acids were studied. The novel compounds showed strong, micromolar and submicromolar affinities to all examined DNA ds-polynucleotides and poly rA-poly rU. The compounds studied showed selectivity towards GC-DNA base pairs over AT-DNA, which included both binding affinity and a strong fluorescence response. CD titrations showed aggregation along the polynucleotide with well-defined supramolecular chirality. The single dipyridinium-bridged dimer showed intercalation at low dye-DNA/RNA ratios. All new cyanine dyes showed potent micromolar antiproliferative activity against cancer cell lines, making them promising theranostic agents.

Applying Bayesian forecasting to predictive toxicology: The probability of innate carcinogenicity to humans of colorants synthesized from benzidine.

The preclinical identification of health hazards relies on the performance (the historic concordance to the respective gold standard) of regulatorily recommended bioassays. However, any testing with less than 100% sensitivity (or 100% specificity) can deliver false results (outcomes discordant to the respective gold standard). Conversely, the predictive values approach (a.k.a. Bayesian forecasting) weighs (1) the performance of the predictive bioassay (battery, or framework) with (2) the prevalence of -positivity to the respective gold standard- in the most representative category to which the test substance can be allocated. Thus, the predictive values approach (PVA) provides the numeric probability for the toxicity to humans of chemicals that, circumstantially, are evaluable only through nonclinical data. Consequently, the PVA improves the predictivity of nonclinical toxicology, and increases the impact of hazard identifications entirely based on preclinical data. This article aimed to introduce the PVA through a worked example. Due to their toxicological homogeneity and public health relevance, the superfamily of colorants synthesized from benzidine (BZ) or some mutagenic congeners was selected (colorings hereafter mentioned as BZ-related-colorants). Through the PVA, the numeric probability of innate carcinogenicity to humans of 259 BZ-related-colorants was either estimated from rodent carcinogenesis bioassays (RCBs) or predicted from methods alternative to the RCB. A discussion was provided on (1) some limitations and implications of the PVA, and (2) the probable significance of the predictive values figured here for 259 BZ-related-colorings.

Efficient Design to Monitor the Site-specific Sustained Release of a Non-Emissive Anticancer Drug.

A pH-responsive smart nanocarrier with significant components was synthesized by conjugating the non-emissive anticancer drug methyl orange and polyethylene glycol derived folate moiety to the backbone of polynorbornene. Complete synthesis procedure and characterization methods of three monomers included in the work: norbornene-derived Chlorambucil (Monomer 1), norbornene grafted with polyethylene glycol, and folic acid (Monomer 2) and norbornene attached methyl orange (Monomer 3) connected to the norbornene backbone through ester linkage were clearly discussed. Finally, the random copolymer CHO PEG FOL METH was synthesized by ring-opening metathesis polymerization (ROMP) using Grubbs' second-generation catalyst. Advanced polymer chromatography (APC) was used to find the final polymer's molecular weight and polydispersity index (PDI). Dynamic light scattering, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were utilized to explore the prodrug's size and morphology. Release experiments of the anticancer drug, Chlorambucil and the coloring agent, methyl orange, were performed at different pH and time. Cell viability assay was carried out for determining the rate of survived cells, followed by the treatment of our final polymer named CHO PEG FOL METH.

An anti-aggregation NIR-II heptamethine-cyanine dye with a stereo-specific cyanine for imaging-guided photothermal therapy.

Due to the hydrophobicity of the cyanine dye and the huge conjugated plane, the cyanine dye is prone to H-aggregation in aqueous solution, and the ultraviolet absorption is blue-shifted. Here, a hydrophilic quaternary stereo-specific cyanine (HQS-Cy) dye has been synthesized and polypeptide based nanoparticles have been prepared, which improve the water solubility of the cyanine in two aspects. First, at the molecular level, the sulfonic acid group increases the water solubility of the dye molecule while the dimethyl-ammonium functional group repels the molecule through the charge-charge interaction, destroying the planar characteristics of the cyanine structure, increasing the molecular distance between the dye molecules, and preventing the accumulation of cyanine. Secondly, at the nano-micelle level, the use of amphiphilic polypeptide blocks to encapsulate the dye increases the water solubility of the dye while also increasing its biocompatibility. The HQS-Cy@P NPs prepared by the above methods exhibit the maximum absorption at 985 nm and maximum fluorescence emission at 1050 nm in aqueous solution. HQS-Cy@P exhibits good photothermal stability and significant photothermal conversion efficiency of about 35.5%, and both in vitro and in vivo studies revealed that it is an efficient system for NIR-II imaging-guided photothermal therapy of cancer.

Pyridine-Embedded Phenothiazinium Dyes as Lysosome-Targeted Photosensitizers for Highly Efficient Photodynamic Antitumor Therapy.

Development of new photosensitizers (PSs) with high photodynamic efficacy and minimal side effects is of great interest in photodynamic therapy (PDT). In this work, we reported several pyridine-embedded phenothiazinium (pyridophenothiazinium) dyes, which could be conveniently synthesized in a few short steps and acted as highly efficient and potent PSs to selectively localize to lysosomes and photosensitively kill cancer cells. Among them, compound 5, which possessed the ability of promoting intracellular reactive oxygen species (ROS) upon light irradiation by almost 40-fold higher than that of methylene blue (MB, a general phenothiazinium-based PS), exhibited a remarkable phototherapeutic index (PI = 53.8) against HT29 cancer cells, leading to eradication of large solid tumors (∼300 mm3) in a xenograft mouse model without apparent side effects. These results suggest that the pyridophenothiazinium dyes developed herein, especially compound 5, may serve as promising lysosome-targeted PSs for efficient photodynamic antitumor therapy.

Post-synthesis strategy to integrate porphyrinic metal-organic frameworks with CuS NPs for synergistic enhanced photo-therapy.

Multifunctional nanotheranostic systems with both therapeutic and imaging functions are highly desired for the development of more effective and less toxic anti-tumor drugs. Herein, a simple but effective method is reported to fabricate a novel PCN-CuS-FA-ICG-based nanoplatform for dual-modal imaging-guided synergistic photothermal/photodynamic therapy. Porphyrinic metal-organic frameworks with CuS NPs are obtained in aqueous solution via a simple post-synthesis strategy. Furthermore, to obtain a more effective therapy, indocyanine green (ICG) was incorporated into the multifunctional theranostic platform to promote the photothermal therapeutic effect. The as-prepared PCN-CuS-FA-ICG not only exhibits an excellent 1O2 generation efficiency under 650 nm irradiation to achieve remarkable photodynamic cell killing, but also presents outstanding photothermal conversion under 808 nm irradiation to destroy tumor tissues by hyperthermia. In particular, the nanotherapeutic agent realized fluorescence and thermal imaging dual-modal imaging-guided cancer treatment. Meanwhile, in vivo experiments confirmed the evident accumulation of nanoparticles (NPs) at local tumors, and tumor growth was inhibited obviously via synergistic photothermal/photodynamic therapy with negligible side effects.

Solochrome cyanine: A histological stain for cobalt-chromium wear particles in metal-on-metal periprosthetic tissues.

Metal-on-metal (MoM) hip arthroplasties produce abundant implant-derived wear debris composed mainly of cobalt (Co) and chromium (Cr). Cobalt-chromium (Co-Cr) wear particles are difficult to identify histologically and need to be distinguished from other wear particle types and endogenous components (e.g., haemosiderin, fibrin) which may be present in MoM periprosthetic tissues. In this study we sought to determine whether histological stains that have an affinity for metals are useful in identifying Co-Cr wear debris in MoM periprosthetic tissues. Histological sections of periprosthetic tissue from 30 failed MoM hip arthroplasties were stained with haematoxylin-eosin (HE), Solochrome Cyanine (SC), Solochrome Azurine (SA) and Perls' Prussian Blue (PB). Sections of periprosthetic tissue from 10 cases of non-MoM arthroplasties using other implant biomaterials, including titanium, ceramic, polymethylmethacrylate (PMMA) and ultra-high molecular weight polyethylene (UHMWP) were similarly analysed. Sections of 10 cases of haemosiderin-containing knee tenosynovial giant cell tumour (TSGCT) were also stained with HE, SC, SA and PB. In MoM periprosthetic tissues, SC stained metal debris in phagocytic macrophages and in the superficial necrotic zone which exhibited little or no trichrome staining for fibrin. In non-MoM periprosthetic tissues, UHMWP, PMMA, ceramic and titanium particles were not stained by SC. Prussian Blue, but not SC or SA, stained haemosiderin deposits in MoM periprosthetic tissues and TSGT. Our findings show that SC staining (most likely Cr-associated) is useful in distinguishing Co-Cr wear particles from other metal/non-metal wear particles types in histological preparations of periprosthetic tissue and that SC reliably distinguishes haemosiderin from Co-Cr wear debris.

A dormant BODIPY-acrolein singlet oxygen photosensitizer intracellularly activated upon adduct formation with cysteine residues.

Here we report the activatable photosensitizer BromoAcroB, a brominated BODIPY dye incorporating a reactive acrolein warhead. The acrolein moiety serves as an intramolecular switch, deactivating the BODIPY dye in its singlet and triplet excited states via internal conversion. Thiolate addition to this moiety disables the intramolecular quenching mechanism restoring the photosensitizing properties of the parent dye, characterized by a quantum yield of singlet oxygen photosensitization of 0.69 ± 0.02. In cell cultures, and upon thiol adduct formation, BromoAcroB induced light-dependent cell death in MRC-5 and HeLa cell lines. Using fluorescence microscopy and upon measuring the low yet non-negligible emission of the activated compound, we show that the phototoxicity of the dormant photosensitizer correlated with the quantity of BromoAcroB adducts generated. BromoAcroB thus serves as a dormant photosensitizer sensitive to intracellular electrophile response. Our results highlight the effective control of a triplet state process by modulation of an unsaturated moiety on the BODIPY scaffold and underscore the mechanistic opportunities arising for controlled singlet oxygen production in cells specifically sensitive to electrophile stress.

Novel ruthenium(ii) and iridium(iii) BODIPY dyes: insights into their application in photodynamic therapy in vitro.

Organic-metal complexes are promising molecules for use in photodynamic therapy (PDT). The aim of this study was to investigate in vitro effects of novel Ru(ii) and Ir(iii) BODIPY complexes for PDT. These hybrid organic-metal molecules (Ru-BD and Ir-BD) have been synthesized via reactions of a BODIPY precursor (BD) with a phenanthroline unit bearing Ru(ii) (3) and novel Ir(iii) (4) compounds. The crystal structures of the new distyryl BODIPY (BD) and Ru(ii) complex (3) are also reported. The photophysical and singlet oxygen generation properties of Ru-BD and Ir-BD were investigated in comparison with unsubstituted BODIPY (BD). Moreover, Ru-BD and Ir-BD have been biologically evaluated in vitro in chronic myeloid leukemia and cervical cancer cell lines in terms of photodynamic therapy efficacy in the presence of BD control. These complexes were not toxic in the dark but red light was needed to induce cell death. These data support the fact that Ru-BD could be accepted as a valuable photosensitizer-drug for further PDT treatment.

The design, synthesis, and evaluation of organic dithienopyrrole-based D-π-A dyes for use as sensitizers in photodynamic therapy.

Dithienopyrrole-based organic dyes that combine an electron-donating moiety (D), a π-conjugated bridge moiety (π), and an electron-accepting moiety (A) were designed and synthesized in short steps by previously developed one-pot Suzuki-Miyaura coupling approach. Absorption wavelengths of the dyes were readily tuned by altering the D and A moieties. The use of a strongly electron-withdrawing cyanopyridone acceptor enabled NIR absorption. A synthesized sensitizer, 2j, exerted potent phototoxicity mainly via a Type I mechanism in cells. A nitrogen atom in the dithienopyrrole ring serves as a connecting point for the introduction of functional building blocks that can improve the properties of sensitizers, which makes this D-π-A sensitizer a valuable template for the further development of sensitizers.

Novel glycoconjugated squaraine dyes for selective optical imaging of cancer cells.

Novel glycoconjugated squaraine dyes were synthesized, which exhibited excellent internalization in tumor cells and are potent fluorogenic imaging probes for tumor selective optical imaging.

Decolorization of textile dye RB19 using volcanic rock matrix immobilized Bacillus thuringiensis cells with surface displayed laccase.

A triplicate volcanic rock matrix-Bacillus thuringiensis-laccase WlacD (VRMs-Bt-WlacD) dye decolorization system was developed. WlacD was displayed on the B. thuringiensis MB174 cell surface to prepare a whole-cell laccase biocatalyst by using two repeat N-terminal domains of autolysin Mbg (Mbgn)2 as the anchoring motif. Immunofluorescence microscopic assays confirmed that the fusion protein (Mbgn)2-WlacD was anchored on the surface of the recombinant B. thuringiensis MB174. After optimization by a single factor test, L 9(34)-orthogonal test, Plackett-Burman test, steepest ascent method, and Box-Behnken response surface methodology, the whole-cell specific laccase activity of B. thuringiensis MB174 was improved to 555.2 U L-1, which was 2.25 times than that of the primary culture condition. Optimized B. thuringiensis MB174 cells were further adsorbed by VRMs to prepare VRMs-Bt-WlacD, an immobilized whole-cell laccase biocatalyst. Decolorization capacity of as-prepared VRMs-Bt-WlacD toward an initial concentration of 500 mg L-1 of an textile dye reactive blue 19 (RB19) aqueous solution reached 72.36% at a solid-to-liquid ratio of 10 g-100 mL. Repeated decolorization-activation operations showed the high decolorization capacity of VRMs-Bt-WlacD and have the potential for large-scale or continuous operations.

Synthesis and application of water-soluble, photoswitchable cyanine dyes for bioorthogonal labeling of cell-surface carbohydrates.

The synthesis of cyanine dyes addressing absorption wavelengths at 550 and 648 nm is reported. Alkyne functionalized dyes were used for bioorthogonal click reactions by labeling of metabolically incorporated sugar-azides on the surface of living neuroblastoma cells, which were applied to direct stochastic optical reconstruction microscopy (dSTORM) for the visualization of cell-surface glycans in the nm-range.

Syntheses and photodynamic activity of some glucose-conjugated BODIPY dyes.

The syntheses of three water-soluble glucose-conjugated BODIPY dyes with different wavelength emissions and studies of their photodynamic therapeutic (PDT) action on human lung cancer A549 cell line are disclosed. Amongst the chosen compounds, the BODIPY dye 4 possessing a glycosylated styryl moiety at the C-3 position showed best PDT property against the A549 cell line. In particular, it induced reactive oxygen species-mediated caspase-8/caspase-3-dependent apoptosis as revealed from the increased sub G1 cell population and changes in cell morphology. These results along with its localization in the endoplasmic reticulum, as revealed by confocal microscopy suggested that mitochondria may not be directly involved in the photo-cytotoxicity of 4. Compound 4 did not induce any dark toxicity to the A549 cells, and was non-toxic to normal lung cells.

Water-Soluble NIR-Absorbing Rylene Chromophores for Selective Staining of Cellular Organelles.

Biocompatible organic dyes emitting in the near-infrared are highly desirable in fluorescence imaging techniques. Herein we report a synthetic approach for building novel small peri-guanidine-fused naphthalene monoimide and perylene monoimide chromophores. The presented structures possess near-infrared absorption and emission, high photostability, and good water solubility. After a fast cellular uptake, they selectively stain mitochondria with a low background in live and fixed cells. They can be additionally modified in a one-step reaction with functional groups for covalent labeling of proteins. The low cytotoxicity allows a long time exposure of live cells to the dyes without the necessity of washing. Successful application in localization super-resolution microscopy was demonstrated in phosphate-buffered saline without any reducing or oxidizing additives.

Laccase-mediated synthesis of a phenoxazine compound with antioxidative and dyeing properties--the optimisation process.

This study demonstrates the optimisation of the main parameters of the laccase-mediated biosynthesis of high-intensity-coloured orange phenoxazine compound, 2-amino-3-oxo-3H-phenoxazine-8-sulfonic acid, and the antioxidative and dyeing properties. Among optimised parameters were the pH value, the activity of laccase, and the high concentration of the precursor as the necessary step in terms of dye synthesis scale-up. The high concentration of the precursor of ca. 10 g/L can be transformed totally by laccase at the activity of 30 U/g during 12 hours, in an optimised and standardised process in nearly 100% yield of synthesis. The obtained dye exhibited good dyeing properties determined according to the ISO standards. Antioxidative activities were detected for phenoxazinone dye using two independent methods, the chemiluminescence assay and the ABTS free radical-scavenging test, with the values of EC50 for the tested phenoxazine dye amounting 189.8 µg/mL and 1428 µg/mL, respectively. Despite the presence of the phenoxazine core in the structure of this dye, no antibacterial capacity was noted.

Supramolecular Dimerization and [2 + 2] Photocycloaddition Reactions of Crown Ether Styryl Dyes Containing a Tethered Ammonium Group: Structure-Property Relationships.

Molecular self-assembly is an effective strategy for controlling the [2 + 2] photocycloaddition reaction of olefins. The geometrical properties of supramolecular assemblies are proven to have a critical effect on the efficiency and selectivity of this photoreaction both in the solid state and in solution, but the role of other factors remains poorly understood. Convenient supramolecular systems to study the structure-property relationships are pseudocyclic dimers spontaneously formed by styryl dyes containing a crown ether moiety and a remote ammonium group. New dyes of this type were synthesized to investigate the effects of structural and electronic factors on the quantitative characteristics of supramolecular dimerization and [2 + 2] photocycloaddition in solution. Variable structural parameters for the styryl dyes were the size and structure of macrocyclic moiety, the nature of heteroaromatic residue, and the length of the ammonioalkyl group attached to this residue. Quantum chemical calculations of the pseudocyclic dimers were performed in order to interpret the relationships between the structure of the ammonium dyes and the efficiency of the supramolecular photoreaction. One of the dimeric complexes was obtained in the crystalline state and studied by X-ray diffraction. The results obtained demonstrate that the photocycloaddition in the pseudocyclic dimers can be dramatically affected by the electronic structure of the styryl moieties, as dependent on the electron-donating ability of the substituents on the benzene ring, and by the conformational flexibility of the pseudocycle, which determines the mobility of the olefinic bonds. The significance of electronic factors is highlighted by the fact that the photocycloaddition quantum yield in geometrically similar dimeric structures varies from ≤10(-4) to 0.38. The latter value is unusually high for olefins in solution.

One-Pot Synthesis, Spectroscopic and Physicochemical Studies of Quinoline Based Blue Emitting Donor-Acceptor Chromophores with Their Biological Application.

Blue emitting cyano substituted isoquinoline dyes were synthesized by one-pot multicomponent reactions (MCRs) of aldehydes, malononitrile, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one and ammonium acetate. Results obtained from spectroscopic (FT-IR, (1)H-NMR, (13)C-NMR, EI-MS) and elemental analysis of synthesized compounds was in good agreement with their chemical structures. UV-vis and fluorescence spectroscopy measurements proved that all compounds are good absorbent and fluorescent. Fluorescence polarity study demonstrated that these compounds were sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including electronic absorption, excitation coefficient, stokes shift, oscillator strength, transition dipole moment and fluorescence quantum yield were investigated in order to explore the analytical potential of synthesized compounds. The anti-bacterial activity of these compounds were first studied in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria then the minimum inhibitory concentration (MIC) was determined with the reference of standard drug chloramphenicol. The results displayed that compound 3 was better inhibitors of both types of the bacteria (Gram-positive and Gram-negative) than chloramphenicol. Graphical Abstract ᅟ.