Complementary experimental techniques were applied to characterize bioapatite nanocrystals from pathological cardiovascular deposits. The investigated collection included the leaflets from aortic valve, leaflets from mitral valve, leaflets from tricuspid valve and calcified aorta's wall. XRD, EDX and FTIR data have shown that all studied samples consist of imperfect apatite with different crystallinity and variable chemical composition. In accordance with TEM data, the crystals of pathological calcified deposits frequently have oblong or rod‐like shape (length of 60‐90 nanometers, width of 20‐30 nanometers). At the same time, in the SEM and TEM experiments, the complex spheroid assemblies and planar sheet‐like shaped formations with crystal structure close to apatite were observed. Probably, the different shape and morphology of the particles are caused by different ways of crystal nucleation and growth, although the exact mechanisms remain an open question.

BackgroundChitosan and its derivates are widely used for biomedical application due to antioxidative, anti-inflammatory, antimicrobial and tissue repair induced properties. Chitosan-based materials also used as a haemostatic agent but influence of different molecular weight and concentration of chitosan on biological response of blood cells is still not clear.The aim of this research was to evaluate interaction between human blood cells and various forms of chitosan-based materials with different molecular weight and chitosan concentration and prove their effectiveness on in-vivo model.MethodsWe used chitosan with molecular weight 200, 500 and 700 kDa and deacetylation rate 80-82 %. For chitosan impregnation of gauze chitosan solutions in 1 % acetic acid with different concentrations (1, 2, 3, 5 %) were used. We used scanning electron microscopy to obtain information about chitosan distribution on cotton surface; Erythrocyte agglutination test and Complete blood count test – for evaluation of interaction between blood cells and chitosan-based materials with different compound. In-vivo studies was performed in 20 Wistar rats to evaluate effectiveness of new dressing.ResultsOur data shown that chitosan can bind erythrocytes in concentration-depend manner that does not depend on its molecular weight. In addition, chitosan-based materials affect selectively human blood cells. Composition of chitosan with cotton materials does not change erythrocyte shape and does not cause agglutination.ConclusionsСotton-chitosan materials have higher adhesive properties to platelets that depend on molecular weight and concentration of chitosan. These materials also change platelets’ shape that probable is one of the most important mechanisms of haemostatic effect. In-vivo studies have shown high effectiveness of 2 % 200 kDa chitosan for stop bleeding from arteries of large diameter.

Bone loss induced by microgravity is a substantial barrier to humans in long-term spaceflight. Recent studies have revealed that icariin (ICA) can attenuate osteoporosis in postmenopausal women and ovariectomized rats. However, whether ICA can protect against microgravity-induced bone loss remains unknown. In this study, the effects of ICA on a hindlimb suspension rodent model were investigated. Two-month-old female Wistar rats were hindlimb suspended and treated with ICA (25 mg·kg·d, i.g.) or a vehicle for 4 weeks (n = 6). The bone mass density of the hindlimbs was analyzed using dual-energy X-ray absorptiometry and micro-CT. mRNA expression of osteogenic genes in the tibia and the content of bone metabolism markers in serum were measured using qRT-PCR and ELISA, respectively. The bone mineral phase was analyzed using X-ray diffraction and atomic spectrometry. The results showed that ICA treatment significantly rescued the hindlimb suspension-induced reduction in bone mineral density, trabecular number and thickness, as well as the increases in trabecular separation and the structure model index. In addition, ICA treatment recovered the decreased bone-related gene expression, including alkaline phosphatase (ALP), bone glaprotein (BGP), and osteoprotegerin/receptor activator of the NF-κB ligand ratio (OPG/RANKL), in the tibia and the decreased bone resorption marker TRACP-5b levels in serum caused by simulated microgravity. Notably, ICA treatment restored the instability of bone biological apatite and the metabolic disorder of bone mineral elicited by simulated microgravity. These results demonstrate that ICA treatment plays osteoprotective roles in bone loss induced by simulated microgravity by inhibiting bone resorption and stabilizing bone biological apatite.

High strength, excellent corrosion resistance, high biocompatibility, osseointegration ability, and low bacteria adhesion are critical properties of metal implants. Additionally, the implant surface plays a critical role as the cell and bacteria host, and the development of a simultaneously antibacterial and biocompatible implant is still a crucial challenge. Copper nanoparticles (CuNPs) could be a promising alternative to silver in antibacterial surface engineering due to low cell toxicity. In our study, we assessed the biocompatibility and antibacterial properties of a PEO (plasma electrolytic oxidation) coating incorporated with CuNPs (Cu nanoparticles). The structural and chemical parameters of the CuNP and PEO coating were studied with TEM/SEM (Transmission Electron Microscopy/Scanning Electron Microscopy), EDX (Energy-Dispersive X-ray Dpectroscopy), and XRD (X-ray Diffraction) methods. Cell toxicity and bacteria adhesion tests were used to prove the surface safety and antibacterial properties. We can conclude that PEO on a ZrNb alloy in Ca–P solution with CuNPs formed a stable ceramic layer incorporated with Cu nanoparticles. The new surface provided better osteoblast adhesion in all time-points compared with the nontreated metal and showed medium grade antibacterial activities. PEO at 450 V provided better antibacterial properties that are recommended for further investigation.