Luminescent silica mesoparticles for protein transduction.

Unlike silica nanoparticles, the potential of silica mesoparticles (SMPs) (i.e. particles of submicron size) for biological applications in particular the in vitro (let alone in vivo) cellular delivery of biological cargo has so far not been sufficiently studied. Here we examine the potential of luminescent (namely, octahedral molybdenum cluster doped) SMPs synthesised by a simple one-pot reaction for the labelling of cells and for protein transduction into larynx carcinoma (Hep-2) cells using GFP as a model protein. Our data demonstrates that the SMPs internalise into the cells within half an hour. This results in cells that detectably luminesce via conventional methods. In addition, the particles are non-toxic both in darkness and upon photo-irradiation. The SMPs were modified to allow their functionalisation by a protein, which then delivered the protein (GFP) efficiently into the cells. Thus, the luminescent SMPs offer a cheap and trackable alternative to existing materials for cellular internalisation of proteins, such as the HIV TAT protein and commercial protein delivery agents (e.g. Pierce™).

Singlet Oxygen Production and Biological Activity of Hexanuclear Chalcocyanide Rhenium Cluster Complexes [{Re6Q8}(CN)6]4- (Q = S, Se, Te).

Octahedral rhenium cluster complexes have recently emerged as relevant building blocks for the design of singlet oxygen photosensitizing materials toward biological applications such as blue-light photodynamic therapy. However, their singlet oxygen generation ability as well as biological properties have been studied only superficially. Herein we investigate in detail the singlet oxygen photogeneration, dark and photoinduced cytotoxicity, cellular uptake kinetics, cellular localization and in vitro photoinduced oxidative stress, and photodynamic cytotoxicity of the series of octahedral rhenium cluster complexes [{Re6Q8}(CN)6]4-, where Q = S, Se, Te. Our results demonstrate that the selenium-containing complex possesses optimal properties in terms of absorption and singlet oxygen productivity. These features coupled with the cellular internalization and low dark toxicity lead to the first photoinduced cytotoxic effect observed for a molecular [{M6Q8}L6] complex, making it a promising object for further study in terms of blue-light PDT.

Nanosized mesoporous metal-organic framework MIL-101 as a nanocarrier for photoactive hexamolybdenum cluster compounds.

Inclusion compounds of photoluminescent hexamolybdenum cluster complexes in the chromium terephthalate metal-organic framework, MIL-101 (MIL, Matérial Institut Lavoisier) were successfully synthesized in two different ways and characterized by means of powder X-Ray diffraction, chemical analysis and nitrogen sorption. Some important functional properties of hexamolybdenum cluster complexes for biological and medical applications, in particular singlet oxygen generation ability, luminescence properties, cellular uptake behavior and cytotoxicity were studied. It was revealed that the inclusion compounds possessed significant singlet oxygen generation activity. The materials obtained showed a low cytotoxicity, thus allowing them to be used in living cells. Confocal microscopy of human larynx carcinoma (Hep-2) cells incubated with the inclusion compounds showed that MIL-101 performed as a nanocarrier adhering to the external cell membrane surface and releasing the cluster complexes which that penetrated into the cells. Moreover, photoinduced generation of reactive oxygen species (ROS) in Hep-2 cells incubated with inclusion compounds was demonstrated. The cluster supported on MIL-101 was shown to possess in vivo phototoxicity.

Cellular internalisation, bioimaging and dark and photodynamic cytotoxicity of silica nanoparticles doped by {Mo6I8}4+ metal clusters.

Silica nanoparticles (SNPs) doped by hexanuclear molybdenum cluster complexes [{Mo6X8}L6]n (X = Cl, Br, or I; L = various inorganic or organic ligands) have been recently suggested as materials with high potential for biomedical applications due to both their outstanding photoluminescence properties and their ability to efficiently generate singlet oxygen upon photoirradiation. However, no studies were undertaken so far to prove this concept. Therefore, here we examined the potential of photoluminescent SNPs doped by {Mo6I8}4+ for applications such as bioimaging and photodynamic therapy using the human epidermoid larynx carcinoma (Hep-2) cell line as a model. Our results demonstrated both: (i) significant luminescence from cells with internalised molybdenum cluster-doped SNPs combined with the low cytotoxicity of particles in the darkness and (ii) significant cytotoxicity of the particles upon photoirradiation. Thus, this research provides strong experimental evidence for high potential of molybdenum-cluster-doped materials in biomedical applications such as optical bioimaging, biolabeling and photodynamic therapy.

Identification of thyroid hormone receptor homologs in the fluke Opisthorchis felineus (Platyhelminthes).

The liver fluke, Opisthorchis felineus of the Opisthorchiidae family, is a well-known causative agent of opisthorchiasis in Russia and Europe. The aim of this work was to identify genes encoding thyroid hormone receptors in O. felineus, and to analyze the expression of possible target genes in response to treatment with exogenous thyroid hormones. We identified two genes encoding thyroid hormone receptors in the O. felineus genome, THRA and THRB. The genes were differentially expressed through the life cycle. The maximal level of mRNA expression of THRA1 and THRB was observed in adult worms. Treatment of the worms with triiodothyronine and thyroxine resulted in an increase in glucose 6-phosphatase mRNA expression and a decrease in malate dehydrogenase mRNA expression, potential gene targets of thyroid hormones. These data indicate that thyroid hormone receptors may perform essential roles in physiological processes in adult O. felineus.

Cytochrome P450 in fluke Opisthorchis felineus: identification and characterization.

Infection with the human liver fluke Opisthorchis felineus is a serious public health problem in Russia and other Eastern Europe countries. The aim of this work was to identify and sequence cytochrome P450 mRNA from O. felineus and to analyze its expression at different developmental stages. We found only one cytochrome P450 in O. felineus. It contains a conserved Pfam00067 domain which was typical of the CYP450 II eukaryotic microsomal type, and a putative transmembrane domain. Additionally, we identified a high degree of homology between a 3D model of O. felineus CYP450 and mammalian CYP2 structures. The level of O. felineus CYP mRNA expression in maritae (adult stage in definitive mammal host) is significantly higher than in metacercaria. This fact indicates an important role of this biotransformation enzyme in the biochemistry of the parasite at the maritae stage.