Publications by authors named "Olga A Efremova"

Here we present a study on the effect of the aspect ratio (AR) of gold nanoparticles on the emission intensity and singlet oxygen production rate of hexamolybdenum cluster-doped silica particles. It was shown that these parameters can be enhanced gradually up to 6.7- and 13-fold with the AR.

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Objective: The aim: To evaluate the structural and functional parameters of the cardiovascular system during atrial fibrillation (AF) in patients after a stroke.

Patients And Methods: Materials and methods: In the main group, we selected 28 patients with non-valvular AF who had previously suffered an ischemic stroke (IS). The comparison group (30 people) included patients with AF without a stroke, comparable in age and gender.

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Photodynamic and photothermal therapies (PDT, and PTT, respectively) are promising candidates for multimodal anticancer therapies (i.e., combinations of therapies), since their action is based on mechanisms that generally cannot be resisted by cancer cells, that is, generation of highly oxidizing oxygen species and high temperature, respectively.

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Monoclonal antibodies (mAb) demonstrate great potential as immunotherapy agents for the treatment of diseases such as cancer as well as tagging for the targeted delivery of multicomponent therapeutic or diagnostic systems. Nevertheless, the large physical size, poor stability of mAbs and abnormal allergic reactions still remain the main issues affecting their generalised use. Single-domain antibodies (sdAb) are seen as the next generation of antibody derived therapeutics and diagnostics.

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Article Synopsis
  • The study investigates how different organic ligands in rhenium cluster complexes affect their biological properties, focusing on cytotoxicity and how they enter and localize within cells.
  • The researchers synthesized and characterized four new rhenium clusters using 1,2,3- and 1,2,4-triazoles, and compared their effects with those using benzotriazole, specifically in cervical cancer (HeLa) and human fibroblast (CRL-4025) cell lines.
  • Findings suggest that benzotriazole's hydrophobic characteristics enhance the cellular uptake of rhenium clusters, leading to stronger binding to DNA and increased cytotoxicity.
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Finding methods that fight bacterial infection or contamination, while minimising our reliance on antibiotics is one of the most pressing needs of this century. Although the utilisation of UV-C light and strong oxidising agents, such as bleach, are still efficacious methods for eliminating bacterial surface contamination, both methods present severe health and/or environmental hazards. Materials with intrinsic photodynamic activity (i.

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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.

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Article Synopsis
  • Octahedral molybdenum and tungsten clusters show promise for use in photodynamic therapy and bioimaging but face challenges due to poor solubility and hydrolysis stability.
  • The newly synthesized water-soluble tungsten cluster [{W I }(DMSO)](NO) is more stable in water than its molybdenum counterpart, making it a stronger candidate for biological applications.
  • Biological tests reveal that this tungsten cluster has significant toxicity against larynx carcinoma cells when exposed to light, while its dark toxicity increases with hydrolysis, potentially due to the formation of clogging nanoparticles in cellular structures.
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Photoactive transition metal compounds that are prone to reversible redox reactions are important for myriad applications, including catalysis, optoelectronics, and sensing. This article describes chemical and electrochemical methods to prepare cluster complex (BuN)[{MoI}Cl], a rare example of a 23 e cluster complex within the family of octahedral clusters of Mo, W, and Re. The low temperature and room temperature crystal structures; electronic structure; and the magnetic, optical, and electrochemical properties of this complex are described.

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Octahedral metal cluster complexes have high potential for biomedical applications. In order to evaluate the benefits of these moieties for combined CT/X-ray luminescence computed tomography, this paper compares photoluminescence, radiodensity and X-ray induced luminescence properties of eight related octahedral molybdenum and tungsten cluster complexes [{MI}L] (where M is Mo or W and L is I, NO, OTs or OH/HO). This article demonstrates that despite the fact that molybdenum cluster complexes are better photoluminescence emitters, tungsten cluster complexes, in particular (BuN)[{WI}I], demonstrate significantly higher X-ray induced luminescence due to a combination of relatively good photoluminescence properties and high X-ray attenuation.

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The octahedral rhenium cluster compound NaH[{ReSe}(P(CHCONH)(CHCOO))] has recently emerged as a very promising X-ray contrast agent for biomedical applications. However, the synthesis of this compound is rather challenging due to the difficulty in controlling the hydrolysis of the initial P(CHCN) ligand during the reaction process. Therefore, in this report we compare the and toxicity of NaH[{ReSe}(P(CHCONH)(CHCOO))] with those of related compounds featuring the fully hydrolysed form of the phosphine ligand, namely NaH[{ReQ}(P(CHCOO))] (Q = S or Se).

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This article describes the synthesis, structures and systematic study of the spectroscopic and redox properties of a series of octahedral molybdenum metal cluster complexes with aromatic sulfonate ligands (BuN)[{MoX}(OTs)] and (BuN)[{MoX}(PhSO)] (where X is Cl, Br or I; OTs is p-toluenesulfonate and PhSO is benzenesulfonate). All the complexes demonstrated photoluminescence in the red region and an ability to generate singlet oxygen. Notably, the highest quantum yields (>0.

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Silica nanoparticles (SNPs) doped by hexanuclear molybdenum cluster complexes [{MoX}L] (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 {MoI} for applications such as bioimaging and photodynamic therapy using the human epidermoid larynx carcinoma (Hep-2) cell line as a model.

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