For the first time, single crystals of Ni3_xMnxBO5:Cu, measuring up to 0.4x0.4x4 mm3, have been grown using the flux technique. The flux used was based on Bi2Mo3O12-B2O3; the addition of CuO served as a solvent component and promoted the growth of Ni3_xMnxBO5:Cu. Energy-dispersive X-ray spectroscopy (EDX) showed that the concentration of copper in the crystal, relative to the flux content was low-approximately 1:8. Subsequently, neutron diffraction, alternating current (AC) magnetization, and electron spin resonance (ESR) were performed on the Ni3_xMnxBO5:Cu compound, which is classified as ludwigite-type compound. Neutron diffraction results confirmed that the Ni3_xMnxBO5:Cu structure belongs to the Pbam space group. Furthermore, AC magnetization and ESR measurements identified three ferrimagnetic phase transitions occurring at 90 K, 95 K, and 150 K, as well as a canonical spin-glass transition near 50 K.

Background and purpose: Polyhydroxyalkanoates (PHAs) are biodegradable polyesters of bacterial origin that are actively studied as matrices for the preparation of nanoparticulate drug delivery systems. The most significant parameters affecting PHAs nanoparticles (NPs) characteristics are polymer composition and the type of surfactant used to stabilize the emulsion during NPs preparation. However, there are only a few studies in the literature investigating the effect of these factors on the characteristics of PHA NPs. Experimental approach: Blank poly(3-hydroxybutyrate) (P3HB) and poly(3-hydroxybutyrate-co-3-hydroxy­valerate) (P3HBV) NPs were produced and characterized in terms of their size, morphology and zeta potential. Poly(vinyl alcohol) (PVA) with various molecular weights (31-50 and 85-124 kDa), as well as Tween 20 (TW20), Tween 80 (TW80), sodium deoxycholate (SDC) and sodium dodecyl sulphate (SDS) were used as surfactants. For NPs that formed stable aqueous suspensions and had the most desirable characteristics (P3HB/PVA31-50 and P3HBV/PVA31-50), hemolytic activity and cytotoxicity to HeLa and C2C12 cells in vitro were determined. Key results: NPs of both P3HB and P3HBV obtained using PVA with the Mw of 31-50 kDa as a surfactant had regular spherical shape, uniform size distribution, average diameter of about 900 nm and zeta potential of -28.5 and -28.7 mV, respectively. PVA85-124, TW20 and TW80, as well as SDC and SDS as surfactants, did not show satisfactory results due to suspension gelation, formation of hollow NPs with irregular shape and poor resuspension after washing and freeze-drying, respectively. P3HB/PVA31-50 and P3HBV/PVA31-50 NPs did not have hemolytic activity and did not show pronounced cytotoxicity to HeLa and C2C12 cells in the concentration range from 10 to 500 μg mL-1, so these samples were regarded as safe and biocompatible. Conclusion: In this study, the effect of various non-ionic and anionic surfactants on the characteristics of P3HB and P3HBV NPs was investigated. PVA31-50 was found to be effective in producing NPs of both studied polymers with good biocompatibility and favorable characteristics, making them suitable for drug delivery applications. In contrast, other studied surfactants, i.e., PVA85-124, TW20, TW80, SDC and SDS, require further investigation. The obtained findings may promote the development of novel PHA-based nanomedicines.

Background and purpose: Cyclophosphamide (CP) is a widely used antitumor and immunosuppressive drug, but it is highly cytotoxic and has carcinogenic and teratogenic potential. To reduce adverse effects of CP therapy and the frequency of its administration, the microencapsulation of CP into biodegradable polymeric matrices can be performed. However, according to the literature, only a few polymers were found suitable to encapsulate CP and achieve its’ sustained release. Experimental approach: In this research, spray-dried cyclophosphamide-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) microparticles were prepared and characterized in terms of their average hydrodynamic diameter, polydispersity index, surface morphology, zeta potential, encapsulation efficiency, drug loading, thermal properties and cytotoxicity against 3T3 cells. Key results: The obtained CP-loaded microparticles had a regular spherical shape, uniform size distribution with an average diameter of 4.21±0.04 μm and zeta potential of -34.2±0.2 mV. The encap­sulation of cyclophosphamide into the PHBV matrix led to a decrease in melting and degradation tempe­ratures and an increase in diameter, glass transition and cold crystallization temperatures compared to blank microparticles. Moreover, microencapsulation of cyclophosphamide lowered its cytotoxicity compared to the pure drug: the number of dead cells in the culture decreased by 28 %, while their metabolic activity increased by 20 %. The cumulative in vitro drug release studies showed a gradual release of CP up to 18 days, so the obtained microparticle formulation can be used as a sustained-release cyclophosphamide delivery system. Conclusion: In this research, a novel cyclophosphamide-loaded platform based on PHBV micro­particles was established and characterized. Overall, this study offers promising prospects for cancer therapy in the future.

Eco-friendly polymer composites in the form of granules based on biodegradable polycaprolactone (PCL) with the inclusion of montmorillonite (MMT) from 5 to 50 wt% were prepared by solution-casting and melt extrusion. The physicochemical properties of the composite granules were studied using FTIR spectroscopy, XRDA, DSC, and TGA methods. The paper presents comparative values of crystallinity of composite granules which depend on the method of measuring (XRDA, DSC). It was shown that the crystallinity of PCL/MMT granules was affected by the preparation method and by the MMT content, and that with increase in MMT content, crystallinity increased by up to 61–67%. The change in crystallinity of the granules also affected its biodegradation in soil. At the end of exposure in soil, the mass loss for the granules prepared by solution-casting was more than 90%, whereas for the composite granules prepared by extrusion it was less than 60%. Applying melt extrusion enabled obtaining intercalated composites with predictable features, whereas only mixed-structure microcomposites could be prepared by solution-casting.

Single crystals of (Mn,Ni,Cu)3BO5 ludwigites have been obtained by a flux technique and studied by XRD, EDX and Raman spectroscopy. The significant difference of the actual Mn/Ni/Cu ratio and the ratio in the flux was found and discussed.

The effect of surface relief profiles of alkanoate-based bionanofilms to the monocyte-macrophages (MN-MPhs) from peripheral blood of patients with atherosclerosis was studied in vitro. Patients were subjected to coronary stenting. Cell morphology and phenotype (expression of CD antigens, levels of production of marker cytokines) in vitro were analyzed before and after the installation of stents. It was shown, that the mean square roughness (Rq) of the bionanofilms determined the variability of cell morphology, CD antigens spectraand activity of production interleukins-6 and -10. Also, it was revealed, that the "activity" of the surface topography of biopolymer substrates depends on the functional state of MNs, isolated in different time points: Before and after stenting the ratios of cell morphotypes and production of cytokines in MN-MPhs differed significantly.

The morphotypes of human macrophages (MPh) were studied in the culture on nano-structured biopolymer substrates, made from polyhydroxyalcanoates (PHAs) of five various monomer compositions, followed by the solvent evaporation. Its surface relief, which was further in direct contact with human cells in vitro, was analyzed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). It was shown, that the features of the micro/nano relief depend on the monomeric composition of the polymer substrates. Monocytes (MN) of patients with atherosclerosis and cardiac ischemia, undergoing stenting and conventional anti-atherosclerotic therapy, were harvested prior and after stenting. MN were isolated and cultured, with the transformation into MPh in direct contact with biopolymer culture substrates with different monomer composition and nano-reliefs, and transformed into MPh, in comparison with the same process on standard culture plastic. Sub-populations of cells with characteristic morphology in each phenotypic class were described, and their quantitative ratios for each sample of polymers were counted as an intermediate result in the development of "smart" material for cardiovascular devices. The results obtained allow us to assume, that the processes of MPh differentiation and polarization in vitro depend not only on the features of the micro/nano relief of biopolymer substrates, but also on the initial state of MN in vivo and general response of patients.

Natalia G. Menzyanova, Svetlana V. Pyatina, Elena D. Nikolaeva, Alexander V. Shabanov, Ivan V. Nemtsev, Dmitry P. Stolyarov, Dmitry B. Dryganov, Eugene V. Sakhnov, Daria A. Vinokurova and Ekaterina I. Shishatskaya-Morphological Aspects of Monocyte/Macrophage Polarization on Biopolymer Scaffolds in Atherosclerosis Patients

The morphology, surface properties and biocompatibility of mixtures of poly-3-hydroxybutyrate with poly-ε-caprolactone, poly-DL-lactide, polyethylene glycol and starch were studied. Differences in the film surface microstructure were revealed using electron microscopy: composites of P(3HB) with PEG and PCL had a more coarse-pored surface compared to the pure P(3HB). Addition of PEG led to a significant increase in surface hydrophilicity. In the culture of mouse NIH 3T3 fibroblasts the following effects were observed: the absence of cytotoxic effect, the presence of cell adhesion and proliferation. Thus, the biocompatibility of the studied composites and their suitability for production of polymer products for cellular technologies was shown

In this study, electrospinning was used to prepare ultrafine fibers from PHAs with different chemical compositions: P(3HB) and copolymers: P(3HB-co-4HB), P(3HB-co-3HV), and P(3HB-co-3HHx). The main process parameters that influence ultrafine fiber diameter and properties (polymer concentration, solution feeding rate, working distance, and applied voltage) have been investigated and their effects evaluated. The study revealed electrospinning parameters for the production of high-quality ultrafine fibers and determined which parameters should be varied to tailor the properties of the products. This study is the first to compare biological and physical-mechanical parameters of PHAs with different chemical compositions as dependent upon the fractions of monomers constituting the polymers and ultrafine fiber orientation. Mechanical strength of aligned ultrafine fibers prepared from different PHAs is higher than that of randomly oriented ones; no significant effect of ultrafine fiber orientation on surface properties has been found. None of the fibrous scaffolds produced by electrospinning from PHAs had any adverse effects on attachment, growth, and viability of NIH 3T3 mouse fibroblast cells, and all of them were found to be suitable for tissue engineering applications.

Ceramic volumetric composites x La_0.7Pb_0.3MnO_3-(1− x )PbTiO_3 ( x = 0.18 and 0.85) were prepared. X-ray investigations have shown that rather low sintering temperature (800 °C) has allowed us to avoid the reaction and interdiffusion between two initial phases. Heat capacity, thermal expansion, and intensive magnetocaloric effect were measured in a wide temperature range. The sample composition has a low influence on temperatures of the ferromagnetic and ferroelectric phase transitions in composites. Electro- and barocaloric effects were determined by analysis in the framework of thermodynamic theory, electric equation of state, Maxwell relationships, and entropy-temperature-pressure phase diagram. Multicaloric efficiency of composites is discussed and compared with that of initial La_0.7Pb_0.3MnO_3 and PbTiO_3 compounds. Variation of a relationship between components can significantly increase both barocaloric and magnetocaloric efficiency of compositional material due to the mechanical stress appearing between grains of different ferroic phases under magnetic field.