The Cell-IQ continuous surveillance system allowed us to establish the following changes in a 14- day culture in vitro: a twofold suppression of the directional migration of multipotent mesenchymal stromal cells of human adipose tissue (MMSC-AT) towards the samples with a microarc calcium phosphate (CP) coating from synthetic hydroxyapatite; a tenfold decrease in the cell mass on the interphase with the samples, which was accompanied by a slight reduction in the expression of membrane determinants of stromal stem cells; and an enhancement of their osteogenic differentiation (osteocalcin secretion and mineralized matrix formation) on the 21st day of the study. Calcium phosphate particles, but not the calcium and phosphorus ions, may trigger the phenotypic transformation of the MMSC-AT behavior in vitro.

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Present day biomedical applications, including magnetic biosensing, demand better understanding of the interactions between living systems and magnetic nanoparticles (MNPs). In this work spherical MNPs of maghemite were obtained by a highly productive laser target evaporation technique. XRD analysis confirmed the inverse spinel structure of the MNPs (space group Fd-3m). The ensemble obeyed a lognormal size distribution with the median value 26.8 nm and dispersion 0.362. Stabilized water-based suspensions were fabricated using electrostatic or steric stabilization by the natural polymer chitosan. The encapsulation of the MNPs by chitosan makes them resistant to the unfavorable factors for colloidal stability typically present in physiological conditions such as pH and high ionic force. Controlled amounts of suspensions were used for in vitro experiments with human blood mononuclear leukocytes (HBMLs) in order to study their morphofunctional response. For sake of comparison the results obtained in the present study were analyzed together with our previous results of the study of similar suspensions with human mesenchymal stem cells. Suspensions with and without chitosan enhanced the secretion of cytokines by a 24-h culture of HBMLs compared to a control without MNPs. At a dose of 2.3, the MTD of chitosan promotes the stimulating effect of MNPs on cells. In the dose range of MNPs 10–1000 MTD, chitosan “inhibits” cellular secretory activity compared to MNPs without chitosan. Both suspensions did not caused cell death by necrosis, hence, the secretion of cytokines is due to the enhancement of the functional activity of HBMLs. Increased accumulation of MNP with chitosan in the cell fraction at 100 MTD for 24 h exposure, may be due to fixation of chitosan on the outer membrane of HBMLs. The discussed results can be used for an addressed design of cell delivery/removal incorporating multiple activities because of cell capability to avoid phagocytosis by immune cells. They are also promising for the field of biosensor development for the detection of magnetic labels.

Artificial enzymatic mimics based on nanoparticles have become a powerful tool for the improvement of analytical performance in the detection of important bioactive compounds. For the first time the intrinsic peroxidase-like activity of Fe-core/carbon shell nanoparticles (Fe@C NPs) was studied. The catalytic process was described by a typical Michaelis-Menten curve for enzyme kinetics, and the results were comparable with those previously published. The high catalytic performance of the Fe@C NPs allows the development of a new simple procedure for glucose determination with a low detection limit of 0.21 mM. To our knowledge, this is the first study showing the ability to generate active oxygen species on the Fe@C surfaces. We suppose that our investigation will open up a new direction in medicinal applications using these promising materials.

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With the aim of simplifying and accelerating the voltammetric analysis of foodstuffs, it is proposed that ultrasound be used in the acid digestion of samples, voltammograms be recorded without removing oxygen, to determine arsenic(III) be determined directly in salts and food supplements soluble in the supporting electrolyte, and arsenic be distilled off. Sample preparation with the distillation of arsenic trichloride from the sample solution is an alternative to wet and dry ashing in the analysis of all type of foodstuffs and various waters.

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