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Frontiers in theranostics are driving the demand for multifunctional nanoagents. Upconversion nanoparticle (UCNP)-based systems activated by near-infrared (NIR) light deeply penetrating biotissue are a powerful tool for the simultaneous diagnosis and therapy of cancer. The intercalation into large polymer micelles of poly(maleic anhydride-alt-1-octadecene) provided the creation of biocompatible UCNPs. The intrinsic properties of UCNPs (core@shell structure NaYF4:Yb3+/Tm3+@NaYF4) embedded in micelles delivered NIR-to-NIR visualization, photothermal therapy, and high drug capacity. Further surface modification of micelles with a thermosensitive polymer (poly-N-vinylcaprolactam) exhibiting a conformation transition provided gradual drug (doxorubicin) release. In addition, the decoration of UCNP micelles with Ag nanoparticles (Ag NPs) synthesized in situ by silver ion reduction enhanced the cytotoxicity of micelles at cell growth temperature. Cell viability assessment on Sk-Br-3, MDA-MB-231, and WI-26 cell lines confirmed this effect. The efficiency of the prepared UCNP complex was evaluated in vivo by Sk-Br-3 xenograft regression in mice for 25 days after peritumoral injection and photoactivation of the lesions with NIR light. The designed polymer micelles hold promise as a photoactivated theranostic agent with quattro-functionalities (NIR absorption, photothermal effect, Ag NP cytotoxicity, and Dox loading) that provides imaging along with chemo- and photothermal therapy enhanced with Ag NPs.

A facile way to prevent the leakage of fatty acid PCM via adsorption on cellulose microfibers is described. The prepared phase-change composites exhibit excellent shape stability, thermal reliability, and adjustable latent heat storage performance.

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for biosensing. However, SERS analysis has several concerns: the signal is limited by a number of molecules and the area of the plasmonic substrate in the laser hotspot, and quantitative analysis in a low-volume droplet is confusing due to the change of concentration during quick drying. The usage of hollow-core microstructured optical fibers (HC-MOFs) is thought to be an effective way to improve SERS sensitivity and limit of detection through the effective irradiation of a small sample volume filling the fiber capillaries. In this paper, we used layer-by-layer assembly as a simple method for the functionalization of fiber capillaries by gold nanoparticles (seeds) with a mean diameter of 8 nm followed by UV-induced chloroauric acid reduction. We also demonstrated a simple and quick technique used for the analysis of the SERS platform formation at every stage through the detection of spectral shifts in the optical transmission of HC-MOFs. The enhancement of the Raman signal of a model analyte Rhodamine 6G was obtained using such type of SERS platform. Thus, a combination of nanostructured gold coating as a SERS-active surface and a hollow-core fiber as a microfluidic channel and a waveguide is perspective for point-of-care medical diagnosis based on liquid biopsy and exhaled air analysis.

Abstract Upconversion nanoparticles (UCNPs) are a promising nanoplatform for bioreagent formation for in vivo imaging, which emit UV and blue light under the action of near-infrared radiation, providing deep tissue penetration and maintaining a high signal-to-noise ratio. In the case of solid tumor visualization, the UCNP surface functionalization is required to ensure a long circulation time, biocompatibility, and non-toxicity. The effective UCNP accumulation in the solid tumors is determined by the disturbed architecture of the vascular network and lymphatic drainage. This work demonstrates an approach to the UCNP biofunctionalization with endogenous polysialic acid for in vivo bioreagent formation. Bioreagents possess a low level of nonspecific protein adsorption and macrophage uptake, which allow the prolongation of the circulation time in the bloodstream up to 3 h. This leads to an intense photoluminescent signal in the tumor.

Anticancer hybrid mineral highly-magnetic protein–tannin vehicles are tunable and controllable external triggers for drug delivery systems. The saturation level of submicron particles of calcium carbonate with magnetic nanoparticles was achieved. The Brillouin light scattering technique and the movement determination of composites in the non-uniform magnetic field, as well as the SEM study of hybrid mineral highly-magnetic composites, made it possible to characterize the magnetic properties of the carriers and determine that 3 freezing/thawing cycles of magnetic nanoparticles are sufficient to obtain an optimal drug carrier. We have demonstrated that doxorubicin and mitoxantrone are effectively encapsulated in vehicles, while the encapsulated drugs are effectively stored in clean water and PBS. Anticancer hybrid mineral highly-magnetic protein–tannin vehicles have a higher cytostatic effect on MCF-7 breast cancer cells because of the best interaction of the cytostatics with DNA due to the inside-out structure compared with the NMUMG breast healthy cell line. Extra magnetic anticancer structures of the core–shell can be potentially used as objects for preserving antitumor drugs over time, due to the higher survival rate compared to the pure substance and the lack of release of antitumor drugs into model fluids.

In the late 1990s, the unique possibilities application of inorganic nanocrystals with anti-Stokes photoluminescence were demonstrated. In a fairly short period, a significant breakthrough has been achieved in this field due to the development of new and modification of existing methods for the synthesis of these nanomaterials, and the expansion of understanding of the photophysical processes occurring in nanocrystals. The interest from the scientific community is due to the exceptional luminescence properties of upconversion nanomaterials, which can convert photons of the near-infrared spectrum to radiation in the visible and UV ranges. This multiquantum process takes place under low-intensity excitation, which largely determines the use of this class of nanomaterials in high-tech fields, including biotechnology, photochemistry, medicine, solar energy, nanosensorics, etc. The goals of this review are to consider the mechanisms of anti-Stokes luminescence, to analyze the synthesis methods, and to demonstrate the applications of fluoride upconversion nanomaterials, in which they have formed a stable scientific and technological niche.

The photocatalytic degradation of organic molecules is one of the effective ways for water purification. At this point, photocatalytic microreactor systems seem to be promising to enhance the versatility of the photoassisted degradation approach. Herein, we propose photoresponsive microcapsules prepared via layer-by-layer assembly of polyelectrolytes on the novel CaCO3/TiO2 composite template cores. The preparation of CaCO3/TiO2 composite particles is challenging because of the poor compatibility of TiO2 and CaCO3 in an aqueous medium. To prepare stable CaCO3/TiO2 composites, TiO2 nanoparticles were loaded into mesoporous CaCO3 microparticles with a freezing-induced loading technique. The inclusion of TiO2 nanoparticles into CaCO3 templates was evaluated with scanning electron microscopy and elemental analysis with respect to their type, concentration, and number of loading iterations. Upon polyelectrolyte shell assembly, the CaCO3 matrix was dissolved, resulting in microreactor capsules loaded with TiO2 nanoparticles. The photoresponsive properties of the resulted capsules were tested by photoinduced degradation of the low-molecule dye rhodamine B in aqueous solution and fluorescently labeled polymer molecules absorbed on the capsule surface under UV light. The exposure of the capsules to UV light resulted in a pronounced degradation of rhodamine B in capsule microvolume and fluorescent molecules on the capsule surface. Finally, the versatility of preparation of multifunctional photocatalytic and magnetically responsive capsules was demonstrated by iterative freezing-induced loading of TiO2 and magnetite Fe3O4 nanoparticles into CaCO3 templates.

In modern biomedical science and developmental biology, there is significant interest in optical tagging to study individual cell behavior and migration in large cellular populations. However, there is currently no tagging system that can be used for labeling individual cells on demand in situ with subsequent discrimination in between and long-term tracking of individual cells. In this article, we demonstrate such a system based on photoconversion of the fluorescent dye rhodamine B co-confined with carbon nanodots in the volume of micron-sized polyelectrolyte capsules. We show that this new fluorescent convertible capsule coding system is robust and is actively uptaken by cell lines while demonstrating low toxicity. Using a variety of cellular lines, we demonstrate how this tagging system can be used for code-like marking and long-term tracking of multiple individual cells in large cellular populations.

We demonstrate a novel approach to the controlled loading of inorganic nanoparticles and proteins into submicron- and micron-sized porous particles. The approach is based on freezing/thawing cycles, which lead to high loading densities. The process was tested for the inclusion of Au, magnetite nanoparticles, and bovine serum albumin in biocompatible vaterite carriers of micron and submicron sizes. The amounts of loaded nanoparticles or substances were adjusted by the number of freezing/thawing cycles. Our method afforded at least a three times higher loading of magnetite nanoparticles and a four times higher loading of protein for micron vaterite particles, in comparison with conventional methods such as adsorption and coprecipitation. The capsules loaded with magnetite nanoparticles by the freezing-induced loading method moved faster in a magnetic field gradient than did the capsules loaded by adsorption or coprecipitation. Our approach allows the preparation of multicomponent nanocomposite materials with designed properties such as remote control (e.g. via the application of an electromagnetic or acoustic field) and cargo unloading. Such materials could be used as multimodal contrast agents, drug delivery systems, and sensors.

Carbon nanodots (CNDs) doped with Tb ions were synthesized using different synthetic routes: hydrothermal treatment of a solution containing carbon source (sodium dextran sulfate) and TbCl3; mixing of CNDs and TbCl3 solutions; freezing-induced loading of Tb and carbon-containing source into pores of CaCO3 microparticles followed by hydrothermal treatment. Binding of Tb ions to CNDs (Tb-CND coupling) was confirmed using size-exclusion chromatography and manifested itself through a decrease of the Tb photoluminescence lifetime signal. The shortest Tb photoluminescence lifetime was observed for samples obtained by hydrothermal synthesis of CaCO3 microparticles where Tb and carbon source were loaded into pores via the freezing-induced process. The same system displays an increase of Tb photoluminescence via energy transfer with excitation at 320–340 nm. Based on the obtained results, freezing-induced loading of cations into CNDs using porous CaCO3 microparticles as reactors is proposed to be a versatile route for the introduction of active components into CNDs. The obtained CNDs with long-lived emission may be used for time-resolved imaging and visualization in living biological samples where time-resolved and long-lived luminescence microscopy is required.

The lanthanide-doped upconversion nanoparticles (UCNPs) gained great attention as nanoplatforms for optical bioimaging and drug delivery systems. In this work, we developed the multimodal system based on UCNPs modified with thermosensitive polymer and Ag nanoparticles (AgNPs), containing chemotherapeutics, such as doxorubicin and flavin mononucleotide, for visualization and therapy. The drug delivery, cytotoxicity and optical properties were studied.

Lanthanide-doped upconversion nanoparticles (UCNPs) are promising bioimaging agents that emit light under near infra-red excitation, capable of penetrating deep in biotissues with a high signal-to-noise ratio. Their successful implementation is principally associated with surface functionalization. Here, we report on UCNP surface modification with highly hydrophilic, endogenous, non-toxic, non-immunogenic colominic acid, conferring "stealth" properties. We proposed surface functionalization of UCNPs based on a two-step strategy, which consists of hydrophilization with polyethyleneimine and attachment of colominic acid by electrostatic or covalent bond formation. Analysis revealed that regardless of the nature of the bond, colominic acid acted as a non-cytotoxic UCNP surface coating with low nonspecific blood protein adsorption. UCNP-colominic acid nanocomplexes exhibited low uptake by macrophages in vitro, which plays an active role in inflammatory reactions. We demonstrated the superiority of colominic acid compared to polyethylene glycol coating in terms of the prolonged circulation time in the bloodstream of small animals when injected intravenously. The colominic acid coating made it possible to prolong the UCNP circulation time up to 3 h. This led to the efficient UCNP accumulation in the inflammation site due to microvascular remodeling, accompanied by an enhanced uptake and retention effect. UCNP-assisted imaging of inflammation in the whole-body mode as well as local visualization of blood vessels were acquired in vivo. These collective findings validate the functional significance of UCNP decoration with colominic acid for their application in bioimaging.

Non-destructive, controllable, remote light-induced release inside cells enables studying of time- and space-specific surface-mediated delivery of bioactive compounds, which is an important approach in a wide range of biomedical tasks, especially those related to the control of cell growth, regenerative medicine, and self-disinfecting structures such as catheters. In this regard, the elaboration of encapsulation and controlled release of oxidative species is in high demand due to its versatile applications. One of the obvious candidates for such species is hydrogen peroxide. However, the delivery of hydrogen peroxide to the site of interest with high temporal and spatial precision remains challenging due to the active and unstable nature of the substance. We hereby present an approach to encapsulate and store a hydrogen peroxide-containing solid compound (sodium percarbonate) in the free-standing arrays of biopolymer-based microchambers. In this regard, we use solid-state encapsulation enabling high payload ability, followed by isolated storage in order to prevent contact of the cargo with water. Monitoring of the release profiles reveals the encapsulation of sodium percarbonate with little leakage for up to 24 hours. Microchambers are fabricated with predetermined size and spatial distribution, which allows the release of extremely small amounts of cargo (10–30 pg) with high spatial accuracy. Microchambers are made of polylactic acid and functionalized by carbon nanodots, which provide biocompatibility and biodegradability of the whole system together with responsiveness towards NIR light. These chambers facilitate both ultrasound-assisted burst release and laser-driven carbon nanoparticle-assisted precise release of extremely small, controlled amounts of a few picograms of hydrogen peroxide in submerged conditions. Microchambers loaded with sodium percarbonate provided adhesion and high viability of mouse fibroblasts over 24 h of exposure. The developed system opens an exciting avenue for prospective delivery routes in a number of areas such as wound healing by time and site-specific release.

Thermoelectric Si 0,65 Ge 0,35 Sb δ materials have been fabricated by spark plasma sintering of Ge-Si-Sb powder mixture. The electronic properties of Si 0,65 Ge 0,35 Sb δ were found to be dependent on the uniformity of mixing of the components, which in turn is determined by the maximum heating temperature during solid-state sintering. Provided the concentration of donor Sb impurity is optimized the thermoelectric figure of merit for the investigated structures can be as high as 0.628 at the temperature of 490 °С, the latter value is comparable with world-known analogues obtained for Si 1- x Ge x P δ .

Theranostics is the direction in modern biomedicine aimed at developing drugs that combine the capabilities of diagnosis and therapy of tumors in one agent. Upconversion nanophosphors (UCNPs) are inorganic crystalline materials that can be used to create a nanoplatform providing diagnostic and therapeutic modalities. They have been proposed as luminescent markers for optical imaging of biological tissue due to their anti-Stokes luminescence, lack of photodegradation and low toxicity. In this article, UCNPs as a theranostic agent for both optical imaging and delivery of anticancer drugs have been offered. To obtain biocompatible nanocomplexes, UCNP surface with a core/shell structure of NaYF4:Yb3+Tm3+/NaYF4 was modified with polylactic acid in the presence of various stabilizers (dextran, polyvinyl alcohol, and poly-N-vinylpyrrolidone). To give the therapeutic modality to the nanocomplex, the antitumor antibiotic doxorubicin was loaded into the polymer shell. The loading efficiency was up to 0.1 mg per 1 mg UCNPs. The toxicity and the intracellular accumulation of nanocomplexes were evaluated in vitro. It was concluded that the modification of UCNPs with polylactic acid provides the transport of doxorubicin, allowing the combination of diagnostic and therapeutic modalities in one agent.

Background: Over the past decades, significant advances have been made in the field of creating nanobioreagents for solving modern medicine problems (Grebenik et al., JBO, 2013). However, the problem of their low accumulation rate in pathological tissue in vivo experiments still remains. First of all, it is associated with the adsorption of blood proteins on the surface of nanobioreagents and the protein layer formation, which significantly changes the surface properties, which leads to their rapid excretion by the reticuloendothelial system. In particular, it is possible to reduce the blood plasma proteins adsorption and increase the time spent in the circulatory system by forming a coating of proteins. Methods: In situ cryоelectron tomography (Cryo-ET) is the only method that allows the experimental observation of protein structures on the nanoparticle’s surface in their natural functional state. The basic principle of the method is to obtain a series of projections of a vitrified sample thin lamella at different tilt angles related to an incident electron beam. Their further processing leads to obtaining the volumetric information about the structure of the sample. The use of a cryo-focused ion beam (Cryo-FIB) in specimen thinning makes it possible to carry out experiments with thin sections of cellular structures and observe the penetration of nanoparticles into the intracellular environment. Results: Upconverting nanophosphors (AN) were used as a nanoplatform for creating a protein coating. To create a protein coating on the AN surface, they were functionalized using an amphiphilic polymer containing carboxyl groups. Then, conjugation with protein molecules from the class of immunoglobulins was carried out by the method of carbodiimide activation. At each stage of synthesis and modification, AN solutions with different size distribution were vitrified for subsequent tomography. After a series of experiments to study the morphology of nanoparticles, an experiment on their successful absorption by cells of the cancer line A549 was carried out. Conclusion: Within this work, a series of in situ Cryo-ET methods were proposed and applied for structural characterization and visualization of the processes of synthesis, modification, and engulfment of nanoparticles into cellular systems. For the first time in its native form, the engulfment of ANF into the internal environment of the A549 cancer line cells was demonstrated.

Au nanoparticles were loaded into halloysite nanotubes by freezing-induced loading method. The loading efficiency and Au nanoparticle distribution were studied by UV–Vis absorption spectroscopy and transmission electron microscopy and compared to those of vacuum impregnation and adsorption from solution loading methods. The freezing-induced loading was found to be the most effective with the loading efficiency up to 85% after 5 loading cycles and the best Au nanoparticle distribution into halloysite nanotubes.

A procedure has been proposed for the preparation of capsules with shells composed of titanium dioxide nanoparticles and polymers via the formation of Pickering emulsions (colloidosomes) followed by layer-by-layer deposition of polyelectrolytes. The feasibility of stabilizing oil droplets of emulsions by spontaneous adsorption of partly hydrophobized nanoparticles of anatase-form titanium dioxide at the oil/water interface has been studied. Conditions have been determined for the formation of stable colloidosomes and the subsequent layer-by-layer deposition of oppositely charged polyelectrolytes onto their surfaces. It has been shown that hydrophobic dyes may be encapsulated using the procedure developed for the preparation of the capsules. The photocatalytic activity of TiO2 particles occurring in the shell has been demonstrated by the example of degradation of Nile red which is incorporated in the oil core of a capsule.

Photopolymerization of nanocomposite materials using near infrared light is one of the unique technologies based on the luminescent properties of lanthanide-doped upconversion nanoparticles (UCNPs). We explored the UCNP-triggered radical polymerization both in oligomer bulk and on the nanoparticle surface in aqueous dispersion. Core/shell UCNPs NaYF4:Yb3+ and Tm3+/NaYF4 with emitting lines in the ultraviolet and blue regions were used to activate a photoinitiator. The study of the bulk photopolymerization in an initially homogeneous reaction mixture showed the UCNP redistribution due to gradient density occurring in the volume, which led to formation of UCNP superlattices and spheres &ldquo, frozen&rdquo, in a polymer matrix. We also developed a strategy of &ldquo, grafting from&rdquo, the surface, providing polymer shell growth directly on the nanoparticles. The photosensitization of the endogenous water-soluble photoinitiator riboflavin by the resonance energy transfer from UCNPs was demonstrated in the course of monomer glycidyl methacrylate polymerization followed by photocrosslinking with poly(ethylene glycol) diacrylate on the nanoparticle surface.

High intensity focused ultrasound (HIFU) is widely used in medical practice, including cancer therapy. Also this approach is promising for remote release of encapsulated drugs in various other biomedical applications where local treatment is needed. Our approach underpins the minimization of HIFU impact on possible degradation of biological tissues and expand the use of HIFU in the controlled release of encapsulated drugs. We demonstrated the efficient ultrasound-induced release of labeled protein (Cy7-BSA) from elaborated nanocomposite microcapsules in vitro an in vivo. The capsule fabrication was done using combination of recently developed freezing-induced loading (FIL) technique and Layer-by-Layer assembly (LbL) used for the preparation of complex multilayer BSA/tannic acid nanocomposite capsules sensitive to HIFU. These capsules contain NIR fluorescent Cy7-labeled BSA in the shell for tracking in vivo and the high concentration of labels inside the capsules resulted in self-quenching provides the real-time detection of the protein once it is released from the capsule. Ultrasound-induced release in vivo of Cy7-labeled BSA initially quenched by magnetite nanoparticles was confirmed by fluorescent tomography. The significant decrease of Cy7 fluorescence under HIFU treatment in vitro was found to be due to a generation of reactive oxygen species and fast dye oxidation. Our results demonstrate that adapted HIFU setup can be used for the directed release of encapsulated substances in vivo under tissue compatible NIR monitoring by fluorescent tomography.

A novel type of microcontainers based on hollow silver alginate microspheres and magnetite nanoparticles is reported as development of recently published technology. Magnetite nanoparticles were incorporated by two methods - co-precipitation with porous calcium carbonate during template formation and adsorption onto CaCO3 particles or microcontainers' shell. Amount of magnetite loaded and microshells size (4.6 to 6.9 μm) were found to depend on the chosen method for magnetite nanoparticles incorporation. Stability of hollow microshells in saline, phosphate buffer and culturing media was studied. Microcontainers' susceptibility to magnetic field was investigated in solutions of varied viscosity, and their group movement velocity under constant magnetic field was evaluated by sequential optical microscopy imaging. Cell viability tests with prepared microshells were performed that demonstrated negligible cytotoxicity effect on human dermal fibroblasts cells. With HeLa cells moderate viability inhibition was found at high carriers:cells ratio at early time points which is attributed to more active and receptor-mediated endocytosis of carriers as well as known cytotoxicity of magnetite in some cancer cells. At 24 and 48 h time points HeLa cells proliferation fully recovers. Reported data opens perspectives for further biomedical-oriented studies and application of this novel kind of microcontainers with a number of techniques applicable for imaging, control and triggered cargo release provided by presence of silver and magnetite nanoparticles in the carriers and their suitability for further versatile functionalization by traditional LbL approach if needed.

Lanthanide-based upconversion nanoparticles attach great attention in theranostics due to their unique physicochemical and optical properties. It is innovative platform possessing peculiar properties for luminescent imaging, temperature mapping, sensing, and therapy. In present work we demonstrate advantages of new luminescent agents based on upconversion nanoparticles and hydrophylic biocompatible polymer.

We present the concept and the experimental demonstration of near-infrared photopolymerization assisted by specially designed upconversion nanophosphors. The principle of this technique is based on conversion of 980 nm laser irradiation to ultraviolet photons subsequently absorbed by photoinitiator. The nonlinearity of upconversion allows for activation of the process locally in the laser beam waist. This approach enables precise fabrication of 3D constructs directly in the volume of photocurable composition. Furthermore, the presented technique is suitable for polymerization of a wide range of photocurable resins as well as gelation of hydrogels for biomedical applications.

The adsorption ability of titanium dioxide samples with nanoscale anatase prepared by the sulfate method and Degussa (Evonik) P25, Hombfine N, and Hombikate UV-100 commercial agents with different compositions and characteristics to extract Nb(V) and Ta(V) ions from a model aqueous system has been investigated for the first time. It is established that the degree of sorption R (%) depends on the sorption conditions and the nature of analyte. It is demonstrated that the degree of sorption of Nb(V) ions in the presence of all samples is the highest (Rmax = 99.9%) for Degussa P25, except for the peroxide-modified samples on which the maximum sorption of Ta(V) ions with Rmax = 99.9% has been attained.

The detection of double bonds in polymers exploited as scaffold materials, e.g. hyaluronic acid (HA) derivatives, is crucial for their further applications. The quantity variations of unsaturated units significantly affect the photoinduced crosslinking degree responsible for the mechanical properties of scaffolds. We demonstrate a simple, selective and rapid quantitative method that enables the detection of double bond moieties in polymers. The approach is based on a reaction with potassium permanganate which is spectrophotometrically confirmed. The effect of glycidyl methacrylate concentration and various reaction catalysts introduced at the stage of HA modification, as well as the change of double bond concentration over time, has been investigated using the proposed method. In addition, the developed quantitative method can be utilized for rapid and efficient detection of unreacted double bonds after photopolymerization as a tool for monitoring conversion over time.

Adsorption of Mo(VI) and W(VI) ions from water with nanosized anatase has been studied. This process depends on sorption conditions (temperature, contact duration, etc.) and sample characteristics (composition, specific surface area, coherent scattering regions, etc.). Maximal recovery efficiency for Mo(VI) and W(VI) was achieved with the use of the samples of commercial Hombifine N (RMo = 99.90 %) and Degussa P25 (RMo = 99.99 %, RW = 99.75 %) and nanosized anatase modified with H2O2 (RMo,W = 99.75 %) under optimal conditions of sorption.

Nanoparticulate anatase and η-TiO2 prepared via a sulfate route have been shown (using powder X-ray diffraction, scanning electron microscopy, X-ray microanalysis, and IR spectroscopy) to differ in micro- and nanoparticle size and elemental composition. The degree of As(V), V(V), and Bi(III) extraction from aqueous solutions (for the last element, a content below its maximum allowable concentration has been reached) using nanoparticulate titania adsorbents depends on their composition, crystal structure, crystallinity, and microstructure. The synthesized anatase and η-TiO2 powders are shown to be potentially attractive carriers of PdCl2-CuCl2/TiO2 catalysts for low-temperature carbon monoxide oxidation in air.

Samples containing anatase and η-TiO2 nanoparticles have been prepared from titanyl sulfate solutions and characterized by X-ray diffraction, transmission electron microscopy, and electron diffraction. Unit-cell parameters of η-TiO2 have been proposed that do not rule out a relationship between the anatase and η-TiO2 structures. The samples containing anatase and η-TiO2 differ in crystallite size and specific surface area and consist of agglomerates of particles of various sizes covered with an amorphous layer. We have studied the effect of synthesis conditions on the ability to prepare a particular titania polymorph with various functional characteristics.

Polyelectrolyte microcapsules functionalized by Fe3O4 nanoparticles have proved to be perspective magnetic resonance (MR) contrast agents. Here we report about submicron-sized capsules with a shell made of poly-L-arginine and dextran sulfate. Such polymers are biodegradable, thus they are suitable to use as components of drug delivery carriers. To functionalize submicrocapsules by magnetite freezing and layer-by-layer method were used. MR study of obtained samples was carried out, and signal intensity change dependencies on submicrocapsules concentration by mass amount of iron oxide (III) nanoparticles were shown. The sample with optimal MR contrast characteristics was found as well, and an ability to use it as a bimodal MR agent was demonstrated.

In this work are shown the prospects of using upconversion nanoparticles (UCNPs) as markers for contrast optical imaging of a tumor. For using nanoparticles for biomedical purposes is implemented a technique for coating nanoparticles with polymers, such as PEG and PSA. This approach provides low non-specific adsorption, which prolongs the circulation of UCNPs in mouse bearing Lewis Lung Cancer (LLC) up to 10 hours. These properties allow nanoparticles to quickly accumulate in the tumor. Effective delivery of particles with different polymer coatings in the tumor is demonstrated with the help of an epiluminescent imaging system.