Smart Graphene Textiles for Biopotential Monitoring: Laser-Tailored Electrochemical Property Enhancement.

While most of the research in graphene-based materials seeks high electroactive surface area and ion intercalation, here, we show an alternative electrochemical behavior that leverages graphene's potential in biosensing. We report a novel approach to fabricate graphene/polymer nanocomposites with near-record conductivity levels of 45 Ω sq-1 and enhanced biocompatibility. This is realized by laser processing of graphene oxide in a sandwich structure with a thin (100 µm) polyethylene terephthalate film on a textile substrate. Such hybrid materials exhibit high conductivity, low polarization, and stability. In addition, the nanocomposites are highly biocompatible, as evidenced by their low cytotoxicity and good skin adhesion. These results demonstrate the potential of graphene/polymer nanocomposites for smart clothing applications.

Adipocyte- and Monocyte-Mediated Vicious Circle of Inflammation and Obesity (Review of Cellular and Molecular Mechanisms).

Monocytes play a key role in the development of metabolic syndrome, and especially obesity. Given the complex features of their development from progenitor cells, whose regulation is mediated by their interactions with bone marrow adipocytes, the importance of a detailed study of the heterogeneous composition of monocytes at the molecular and systemic levels becomes clear. Research argues for monocytes as indicators of changes in the body's metabolism and the possibility of developing therapeutic strategies to combat obesity and components of metabolic syndrome based on manipulations of the monocyte compound of the immune response. An in-depth study of the heterogeneity of bone-marrow-derived monocytes and adipocytes could provide answers to many questions about the pathogenesis of obesity and reveal their therapeutic potential.

Signal Pathways and microRNAs in Osteosarcoma Growth and the Dual Role of Mesenchymal Stem Cells in Oncogenesis.

The major challenges in Osteosarcoma (OS) therapy are its heterogeneity and drug resistance. The development of new therapeutic approaches to overcome the major growth mechanisms of OS is urgently needed. The search for specific molecular targets and promising innovative approaches in OS therapy, including drug delivery methods, is an urgent problem. Modern regenerative medicine focuses on harnessing the potential of mesenchymal stem cells (MSCs) because they have low immunogenicity. MSCs are important cells that have received considerable attention in cancer research. Currently, new cell-based methods for using MSCs in medicine are being actively investigated and tested, especially as carriers for chemotherapeutics, nanoparticles, and photosensitizers. However, despite the inexhaustible regenerative potential and known anticancer properties of MSCs, they may trigger the development and progression of bone tumors. A better understanding of the complex cellular and molecular mechanisms of OS pathogenesis is essential to identify novel molecular effectors involved in oncogenesis. The current review focuses on signaling pathways and miRNAs involved in the development of OS and describes the role of MSCs in oncogenesis and their potential for antitumor cell-based therapy.

Endothelial Cell Behavior and Nitric Oxide Production on a-C:H:SiOx-Coated Ti-6Al-4V Substrate.

This paper focuses on the surface modification of the Ti-6Al-4V alloy substrate via a-C:H:SiOx coating deposition. Research results concern the a-C:H:SiOx coating structure, investigated using transmission electron microscopy and in vitro endothelization to study the coating. Based on the analysis of the atomic radial distribution function, a model is proposed for the atomic short-range order structure of the a-C:H:SiOx coating, and chemical bonds (C-O, C-C, Si-C, Si-O, and Si-Si) are identified. It is shown that the a-C:H:SiOx coating does not possess prolonged cytotoxicity in relation to EA.hy926 endothelial cells. In vitro investigations showed that the adhesion, cell number, and nitric oxide production by EA.hy926 endothelial cells on the a-C:H:SiOx-coated Ti-6Al-4V substrate are significantly lower than those on the uncoated surface. The findings suggest that the a-C:H:SiOx coating can reduce the risk of endothelial cell hyperproliferation on implants and medical devices, including mechanical prosthetic heart valves, endovascular stents, and mechanical circulatory support devices.

Engineered Fibrous NiTi Scaffolds with Cultured Hepatocytes for Liver Regeneration in Rats.

At present, the use of alternative systems to replenish the lost functions of hepatic metabolism and partial replacement of liver organ failure is relevant, due to an increase in the incidence of various liver disorders, insufficiency, and cost of organs for transplantation, as well as the high cost of using the artificial liver systems. The development of low-cost intracorporeal systems for maintaining hepatic metabolism using tissue engineering, as a bridge before liver transplantation or completely replacing liver function, deserves special attention. In vivo applications of intracorporeal fibrous nickel-titanium scaffolds (FNTSs) with cultured hepatocytes are described. Hepatocytes cultured in FNTSs are superior to their injections in terms of liver function, survival time, and recovery in a CCl4-induced cirrhosis rats' model. 232 animals were divided into 5 groups: control, CCl4-induced cirrhosis, CCl4-induced cirrhosis followed by implantation of cell-free FNTSs (sham surgery), CCl4-induced cirrhosis followed by infusion of hepatocytes (2 mL, 107 cells/mL), and CCl4-induced cirrhosis followed by FNTS implantation with hepatocytes. Restoration of hepatocyte function in the FNTS implantation with the hepatocytes group was accompanied by a significant decrease in the level of aspartate aminotransferase (AsAT) in blood serum compared to the cirrhosis group. A significant decrease in the level of AsAT was noted after 15 days in the infused hepatocytes group. However, on the 30th day, the AsAT level increased and was close to the cirrhosis group due to the short-term effect after the introduction of hepatocytes without a scaffold. The changes in alanine aminotransferase (AlAT), alkaline phosphatase (AlP), total and direct bilirubin, serum protein, triacylglycerol, lactate, albumin, and lipoproteins were similar to those in AsAT. The survival time of animals was significantly longer in the FNTS implantation with hepatocytes group. The obtained results showed the scaffolds' ability to support hepatocellular metabolism. The development of hepatocytes in FNTS was studied in vivo using 12 animals using scanning electron microscopy. Hepatocytes demonstrated good adhesion to the scaffold wireframe and survival in allogeneic conditions. Mature tissue, including cellular and fibrous, filled the scaffold space by 98% in 28 days. The study shows the extent to which an implantable "auxiliary liver" compensates for the lack of liver function without replacement in rats.

Morphofunctional reaction of leukocytes and platelets in in vitro contact with a-C:H:SiOx -coated Ti-6Al-4V substrate.

The article deals with the plasma-assisted chemical vapor deposition of 0.3-1.4 µm thick a-C:H:SiOx films in a mixture of argon and polyphenylmethylsiloxane vapor onto the Ti-6Al-4V alloy substrate, which is often used as an implant material. The a-C:H:SiOx film structure is studied by the Fourier-transform infrared and Raman spectroscopies. The pull-off adhesion test assesses the adhesive strength of a-C:H:SiOx films, and the ball-on-disk method is employed to measure their wear rate and friction coefficient. According to these studies, a-C:H:SiOx films are highly adhesive to the Ti-6Al-4V substrate, have low (0.056) friction coefficient and wear rate (9.8 × 10-8  mm3  N-1  m-1 ) in phosphate-buffered saline at 40°C. In vitro studies show neither thrombogenicity nor cytotoxicity of the a-C:H:SiOx film for the human blood mononuclear cells (hBMNCs). The in vitro contact between the hBMNC culture and a-C:H:SiOx films 0.8-1.4 µm thick deposited onto Ti-6Al-4V substrates reduces a 24-hour secretion of pro-inflammatory cytokines and chemokines IL-8, IL-17, TNFα, RANTES, and MCP-1. This reduction is more significant when the film thickness is 1.4 µm and implies its potential anti-inflammatory effect and possible application in cardiovascular surgery. The dependence is suggested for the concentration of anti-inflammatory cytokines and chemokines and the a-C:H:SiOx film thickness, which correlates with the surface wettability and electrostatic potential. The article discusses the possible applications of the anti-inflammatory effect and low thrombogenicity of a-C:H:SiOx films in cardiovascular surgery.

RF Magnetron Sputtering of Substituted Hydroxyapatite for Deposition of Biocoatings.

Functionalization of titanium (Ti)-based alloy implant surfaces by deposition of calcium phosphates (CaP) has been widely recognized. Substituted hydroxyapatites (HA) allow the coating properties to be tailored based on the use of different Ca substitutes. The formation of antibacterial CaP coatings with the incorporation of Zn or Cu by an RF magnetron sputtering is proposed. The influence of RF magnetron targets elemental composition and structure in the case of Zn-HA and Cu-HA, and the influence of substrate's grain size, the substrate's temperature during the deposition, and post-deposition heat treatment (HT) on the resulting coatings are represented. Sintering the targets at 1150 °C resulted in a noticeable structural change with an increase in cell volume and lattice parameters for substituted HA. The deposition rate of Cu-HA and Zn-HA was notably higher compared to stochiometric HA (10.5 and 10) nm/min vs. 9 ± 0.5 nm/min, respectively. At the substrate temperature below 100 °C, all deposited coatings were found to be amorphous with an atomic short-range order corresponding to the {300} plane of crystalline HA. All deposited coatings were found to be hyper-stochiometric with Ca/P ratios varying from 1.9 to 2.5. An increase in the substrate temperature to 200 °C resulted in the formation of equiaxed grain structure on both coarse-grained (CG) and nanostructured (NS) Ti. The use of NS Ti notably increased the scratch resistance of the deposited coatings from18 ± 1 N to 22 ± 2 N. Influence of HT in air or Ar atmosphere is also discussed. Thus, the deposition of Zn- or Cu-containing CaP is a complex process that could be fine-tuned using the obtained research results.

Heparin and Heparin-Based Drug Delivery Systems: Pleiotropic Molecular Effects at Multiple Drug Resistance of Osteosarcoma and Immune Cells.

One of the main problems of modern health care is the growing number of oncological diseases both in the elderly and young population. Inadequately effective chemotherapy, which remains the main method of cancer control, is largely associated with the emergence of multidrug resistance in tumor cells. The search for new solutions to overcome the resistance of malignant cells to pharmacological agents is being actively pursued. Another serious problem is immunosuppression caused both by the tumor cells themselves and by antitumor drugs. Of great interest in this context is heparin, a biomolecule belonging to the class of glycosaminoglycans and possessing a broad spectrum of biological activity, including immunomodulatory and antitumor properties. In the context of the rapid development of the new field of "osteoimmunology," which focuses on the collaboration of bone and immune cells, heparin and delivery systems based on it may be of intriguing importance for the oncotherapy of malignant bone tumors. Osteosarcoma is a rare but highly aggressive, chemoresistant malignant tumor that affects young adults and is characterized by constant recurrence and metastasis. This review describes the direct and immune-mediated regulatory effects of heparin and drug delivery systems based on it on the molecular mechanisms of (multiple) drug resistance in (onco) pathological conditions of bone tissue, especially osteosarcoma.

MicroRNA Regulation of Bone Marrow Mesenchymal Stem Cells in the Development of Osteoporosis in Obesity.

Obesity and osteoporosis are global health problems characterized by high rates of prevalence and mortality due to complications. As people with visceral obesity age, the adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) increases, and adipocytes become the predominant stromal cells in the bone marrow microenvironment, which hinders the physiological regeneration and mineralization of bone tissue. Primary and secondary osteoporosis remain severe progressive diseases. Both osteoporosis and obesity are associated with microRNAs (miRNAs) that induce adipogenesis and osteoresorption. This review presents analyses of the roles and clinical potential of miRNAs in the epigenetic control of BMSC differentiation and the formation and function of osteoclasts in osteoporosis with and without obesity. Understanding the fine-tuned regulation of the expression of genes critical for the balance of osteogenesis/osteolysis processes may provide hope for the development of effective and safe osteoporosis therapies in the future.

Nitrogen-doped titanium dioxide films fabricated via magnetron sputtering for vascular stent biocompatibility improvement.

Nowadays, vascular stents are commonly used to treat cardiovascular diseases. This article focuses on the influence of nitrogen doping of titanium dioxide thin films, utilized for coating metallic stents to improve their biological properties and biocompatibility. The hereby-investigated titanium oxide thin films are fabricated by magnetron sputtering in a reactive gas atmosphere consisting of argon and oxygen in the first case and argon, nitrogen and oxygen in the second case. Control of the nitrogen and oxygen gas flow rates, and hence their mixing ratios, allows adjustment of the nitrogen-doping level within the titanium dioxide thin films. A correlation of the thin film internal structure on the in vitro behavior of human mesenchymal stem cells derived from adipose tissue is hereby demonstrated. Different nitrogen doping levels affect the surface energy, the wettability, the cell adhesion and thus the cellular proliferation on top of the thin films. The surface colonization of cells on titanium dioxide thin films decreases up to a nitrogen-doping level of âˆ¼ 3.75 at.%, which is associated with a decreasing polar component of the surface energy. For non-doped titanium dioxide thin films, a weak chondrogenesis of adult human adipose-derived mesenchymal stem cells with lower chondrogenic differentiation compared to glass is observed. An increasing nitrogen-doping level leads to linear increase in the chondrogenic differentiation rate, which is comparable to the control value of uncoated glass. Other investigated differentiated cell types do not display this behavior.

UMAOH Calcium Phosphate Coatings Designed for Drug Delivery: Vancomycin, 5-Fluorouracil, Interferon α-2b Case.

Drug delivery systems based on calcium phosphate (CaP) coatings have been recently recognized as beneficial drug delivery systems in complex cases of bone diseases for admission of drugs in the localized area, simultaneously inducing osteoinduction because of the bioavailable Ca and P ions. However, micro-arc oxidation (MAO) deposition of CaP does not allow for the formation of a coating with sufficient interconnected porosity for drug delivery purposes. Here, we report on the method to deposit CaP-based coatings using a new hybrid ultrasound-assisted MAO (UMAOH) method for deposition of coatings for drug delivery that could carry various types of drugs, such as cytostatic, antibacterial, or immunomodulatory compositions. Application of UMAOH resulted in coatings with an Ra roughness equal to 3.5 µm, a thickness of 50-55 µm, and a combination of high values of internal and surface porosity, 39 and 28%, respectively. The coating is represented by the monetite phase that is distributed in the matrix of amorphous CaP. Optimal conditions of coating deposition have been determined and used for drug delivery by impregnation with Vancomycin, 5-Fluorouracil, and Interferon-α-2b. Cytotoxicity and antimicrobial activity of the manufactured drug-carrying coatings have been studied using the three different cell lines and methicillin-resistant S. aureus.

In Vitro Biodegradation of a-C:H:SiOx Films on Ti-6Al-4V Alloy.

This paper focuses mainly on the in vitro study of a five-week biodegradation of a-C:H:SiOx films of different thickness, obtained by plasma-assisted chemical vapor deposition onto Ti-6Al-4V alloy substrate using its pulsed bipolar biasing. In vitro immersion of a-C:H:SiOx films in a solution of 0.9% NaCl was used. It is shown how the a-C:H:SiOx film thickness (0.5-3 µm) affects the surface morphology, adhesive strength, and Na+ and Cl- precipitation on the film surface from the NaCl solution. With increasing film thickness, the roughness indices are reducing a little. The adhesive strength of the a-C:H:SiOx films to metal substrate corresponds to quality HF1 (0.5 µm in thickness) and HF2-HF3 (1.5-3 µm in thickness) of the Rockwell hardness test (VDI 3198) that defines strong interfacial adhesion and is usually applied in practice. The morphometric analysis of the film surface shows that on a-C:H:SiOx-coated Ti-6Al-4V alloy surface, the area occupied by the grains of sodium chloride is lower than on the uncoated surface. The reduction in the ion precipitation from 0.9% NaCl onto the film surface depended on the elemental composition of the surface layer conditioned by the thickness growth of the a-C:H:SiOx film. Based on the results of energy dispersive X-ray spectroscopy, the multiple regression equations are suggested to explain the effect of the elemental composition of the a-C:H:SiOx film on the decreased Na+ and Cl- precipitation. As a result, the a-C:H:SiOx films successfully combine good adhesion strength and rare ion precipitation and thus are rather promising for medical applications on cardiovascular stents and/or friction parts of heart pumps.

Microcapsule-Based Dose-Dependent Regulation of the Lifespan and Behavior of Adipose-Derived MSCs as a Cell-Mediated Delivery System: In Vitro Study.

The development of "biohybrid" drug delivery systems (DDS) based on mesenchymal stem/stromal cells (MSCs) is an important focus of current biotechnology research, particularly in the areas of oncotheranostics, regenerative medicine, and tissue bioengineering. However, the behavior of MSCs at sites of inflammation and tumor growth is relevant to potential tumor transformation, immunosuppression, the inhibition or stimulation of tumor growth, metastasis, and angiogenesis. Therefore, the concept was formulated to control the lifespan of MSCs for a specific time sufficient for drug delivery to the target tissue by varying the number of internalized microcontainers. The current study addressed the time-dependent in vitro assessment of the viability, migration, and division of human adipose-derived MSCs (hAMSCs) as a function of the dose of internalized polyelectrolyte microcapsules prepared using a layer-by-layer technique. Polystyrene sulfonate (PSS)­poly(allylamine hydrochloride) (PAH)-coated spherical micrometer-sized (diameter ~2−3 µm) vaterite (CaCO3) microcapsules (PAH-PSS)6 with the capping PSS layer were prepared after dissolution of the CaCO3 core template. The Cell-IQ phase contrast imaging results showed that hAMSCs internalized all (PAH-PSS)6 microcapsules saturating the intercellular medium (5−90 particles per cell). A strong (r > 0.7) linear dose-dependent and time-dependent (up to 8 days) regression was observed between the in vitro decrease in cell viability and the number of internalized microvesicles. The approximate time-to-complete-death of hAMSCs at different concentrations of microcapsules in culture was 428 h (1:5 ratio), 339 h (1:10), 252 h (1:20), 247 h (1:45), and 170 h (1:90 ratio). By varying the number of microcontainers loaded into the cells (from 1:10 to 1:90), a dose-dependent exponential decrease in both the movement rate and division rate of hAMSCs was observed. A real-time cell analysis (RTCA) of the effect of (PAH-PSS)6 microcapsules (from 1:5 to 1:20) on hAMSCs also showed a dose- and time-dependent decrease in cell longevity after a 50h study at ratios of 1:10 and 1:20. The incorporation of microcapsules (1:5, 1:20, and 1:45) resulted in a dose-dependent increase in 24−48 h secretion of GRO-α (CXCL1), MIF, and SDF-1α (CXCL12) chemokines in hAMSC culture. In turn, the normalization or inhibition of chemokine secretion occurred after 72 h, except for MIF levels below 5−20 microcapsules, which were internalized by MSCs. Thus, the proposed concept of controlling the lifespan of MSC-based DDS using a dose of internalized PAH-PSS microcapsules could be useful for biomedical applications. (PAH-PSS)6 microcapsule ratios of 1:5 and 1:10 have little effect on the lifespan of hAMSCs for a long time (up to 14−18 days), which can be recommended for regenerative therapy and tissue bioengineering associated with low oncological risk. The microcapsule ratios of 1:20 and 1:45 did not significantly restrict the migratory activity of hAMSCs-based DDS during the time interval required for tissue delivery (up to 4−5 days), followed by cell death after 10 days. Therefore, such doses of microcapsules can be used for hAMSC-based DDS in oncotheranostics.

Calcium Chelidonate: Semi-Synthesis, Crystallography, and Osteoinductive Activity In Vitro and In Vivo.

Calcium chelidonate [Ca(ChA)(H2O)3]n was obtained by semi-synthesis using natural chelidonic acid. The structure of the molecular complex was determined by X-ray diffraction analysis. The asymmetric unit of [Ca(ChA)(H2O)3]n includes chelidonic acid coordinated through three oxygen atoms, and three water ligands. The oxygen atoms of acid and oxygen atoms of water from each asymmetric unit are also coordinated to the calcium of another one, forming an infinite linear complex. Calcium geometry is close to the trigonal dodecahedron (D2d). The intra-complex hydrogen bonds additionally stabilize the linear species, which are parallel to the axis. In turn the linear species are packed into the 3D structure through mutual intercomplex hydrogen bonds. The osteogenic activity of the semi-synthetic CaChA was studied in vitro on 21-day hAMMSC culture and in vivo in mice using ectopic (subcutaneous) implantation of CaP-coated Ti plates saturated in vitro with syngeneic bone marrow. The enhanced extracellular matrix ECM mineralization in vitro and ectopic bone tissue formation in situ occurred while a water solution of calcium chelidonate at a dose of 10 mg/kg was used. The test substance promotes human adipose-derived multipotent mesenchymal stromal/stem cells (hAMMSCs), as well as mouse MSCs to differentiate into osteoblasts in vitro and in vivo, respectively. Calcium chelidonate is non-toxic and can stimulate osteoinductive processes.

Homeostatic and endocrine responses as the basis for systemic therapy with medical gases: ozone, xenon and molecular hydrogen.

Among medical gases, including gases used therapeutically, this review discusses the comparative physiological activity of three gases - ozone (O3), xenon (Xe) and molecular hydrogen (H2), which together form representatives of three types of substances - typical oxidizing, inert, and typical reducing agents. Upon analysis of published and proprietary data, we concluded that these three medical gases can manipulate the neuroendocrine system, by modulating the production or release of hormones via the hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-gonadal axes, or the gastrointestinal pathway. With repeated administration of the gases over time, these modulations become a predictable consequence of conditioned homeostatic reflexes, resulting in regulation of physiological activity. For example, the regular activation of the unconditioned defense reflex in response to repeated intoxication by ozone leads to the formation of an anticipatory stable conditioned response, which counteracts the toxic action of O3. The concept of a Pavlovian conditioned reflex (or hormoligosis) is a brief metaphor for the understanding the therapeutic effect of systemic ozone therapy.

Amorphous-Crystalline Calcium Phosphate Coating Promotes In Vitro Growth of Tumor-Derived Jurkat T Cells Activated by Anti-CD2/CD3/CD28 Antibodies.

A modern trend in traumatology, orthopedics, and implantology is the development of materials and coatings with an amorphous-crystalline structure that exhibits excellent biocopatibility. The structure and physico-chemical and biological properties of calcium phosphate (CaP) coatings deposited on Ti plates using the micro-arc oxidation (MAO) method under different voltages (200, 250, and 300 V) were studied. Amorphous, nanocrystalline, and microcrystalline statesof CaHPO4 and ß-Ca2P2O7 were observed in the coatings using TEM and XRD. The increase in MAO voltage resulted in augmentation of the surface roughness Ra from 2.5 to 6.5 µm, mass from 10 to 25 mg, thickness from 50 to 105 µm, and Ca/P ratio from 0.3 to 0.6. The electrical potential (EP) of the CaP coatings changed from -456 to -535 mV, while the zeta potential (ZP) decreased from -53 to -40 mV following an increase in the values of the MAO voltage. Numerous correlations of physical and chemical indices of CaP coatings were estimated. A decrease in the ZP magnitudes of CaP coatings deposited at 200-250 V was strongly associated with elevated hTERT expression in tumor-derived Jurkat T cells preliminarily activated with anti-CD2/CD3/CD28 antibodies and then contacted in vitro with CaP-coated samples for 14 days. In turn, in vitro survival of CD4+ subsets was enhanced, with proinflammatory cytokine secretion of activated Jurkat T cells. Thus, the applied MAO voltage allowed the regulation of the physicochemical properties of amorphous-crystalline CaP-coatings on Ti substrates to a certain extent. This method may be used as a technological mechanism to trigger the behavior of cells through contact with micro-arc CaP coatings. The possible role of negative ZP and Ca2+ as effectors of the biological effects of amorphous-crystalline CaP coatings is discussed. Micro-arc CaP coatings should be carefully tested to determine their suitability for use in patients with chronic lymphoid malignancies.

Osteogenic Differentiation Factors of Multipotent Mesenchymal Stromal Cells in the Current Understanding.

BACKGROUND: Molecular genetic mechanisms, signaling pathways, conditions, factors, and markers of the osteogenic differentiation of mesenchymal stem cells (MSCs) are being actively studied and are among the most studied areas in the field of cellular technology. This attention is largely due to the mounting contradictions in the seemingly classical knowledge and the constant updating of results in the analyzed areas. In this regard, we focus on the main classical concepts and some new factors and mechanisms that have a noticeable regulatory effect on the differentiation potential of postnatal MSCs. RESULTS: This review considers the importance of the sources of MSCs for the realization of their differentiation potential, molecular genetic factors and signaling pathways of MSC differentiation, the role of inflammatory cytokines and chemokines in osteogenesis, biomechanical signals, and the effect of conformational changes in the cellular cytoskeleton on MSC differentiation. CONCLUSION: It is concluded that it is necessary to move from studies focused on the effects of local genes to those taking multiple measurements of the gene-regulatory profile and the biomolecules critical for the implementation of numerous, incompletely studied osteogenic factors of endogenous and exogenous origin. Among the cornerstones of future (epi)genetic studies, whether osteomodulatory effects are realized through specific signaling pathways and/or whether cross-signaling with known genes drives the osteogenic differentiation of MSCs remains to be determined.

Effect of working gas on physicochemical and biological properties of CaP coatings deposited by RFMS.

Thin calcium phosphate (CaP) coatings were deposited on titanium substrates by radio frequency magnetron sputtering of hydroxyapatite target in neon (Ne), argon (Ar), krypton (Kr) and xenon (Xe). The influence of the working gas (Ne, Ar, Kr and Xe) on the wettability and biodegradation in the RPMI 1640 synthetic culture medium of the CaP coatings was investigated. This paper is the first comprehensive study of working gas effect on properties of the CaP coatings. There was an increase in the polar component of surface free energy (SFE) and a decrease in the dispersion component of SFE with an increase in the atomic mass of the working gas. All CaP coatings had a pronounced protective effect, reducing double the number of dead cells in culture compared to the Ti control. The most soluble CaP coatings formed in the atmosphere of Xe stimulated the hAMMSCs division, which led to an increase in the total number of cells (208% of the initial culture). Samples with CaP coatings formed in an inert gas atmosphere increased the gene expression (ALPL, BMP6, BMP2)in vitro. The most biocompatible coatings were those formed in the atmosphere of Xe and Ar.

Costimulatory Effect of Rough Calcium Phosphate Coating and Blood Mononuclear Cells on Adipose-Derived Mesenchymal Stem Cells In Vitro as a Model of In Vivo Tissue Repair.

Calcium phosphate (CaP) materials do not always induce ectopic vascularization and bone formation; the reasons remain unclear, and there are active discussions of potential roles for post-implantation hematoma, circulating immune and stem cells, and pericytes, but studies on adipose-derived stem cells (AMSCs) in this context are lacking. The rough (average surface roughness Ra = 2-5 µm) scaffold-like CaP coating deposited on pure titanium plates by the microarc oxidation method was used to investigate its subcutaneous vascularization in CBA/CaLac mice and in vitro effect on cellular and molecular crosstalk between human blood mononuclear cells (hBMNCs) and AMSCs (hAMSCs). Postoperative hematoma development on the CaP surface lasting 1-3 weeks may play a key role in the microvessel elongation and invasion into the CaP relief at the end of the 3rd week of injury and BMNC migration required for enhanced wound healing in mice. Satisfactory osteogenic and chondrogenic differentiation but poor adipogenic differentiation of hAMSCs on the rough CaP surface were detected in vitro by differential cell staining. The fractions of CD73+ (62%), CD90+ (0.24%), and CD105+ (0.41%) BMNCs may be a source of autologous circulating stem/progenitor cells for the subcutis reparation, but allogenic hBMNC participation is mainly related to the effects of CD4+ T cells co-stimulated with CaP coating on the in vitro recruitment of hAMSCs, their secretion of angiogenic and osteomodulatory molecules, and the increase in osteogenic features within the period of in vivo vascularization. Cellular and molecular crosstalk between BMNCs and AMSCs is a model of effective subcutis repair. Rough CaP surface enhanced angio- and osteogenic signaling between cells. We believe that preconditioning and/or co-transplantation of hAMSCs with hBMNCs may broaden their potential in applications related to post-implantation tissue repair and bone bioengineering caused by microarc CaP coating.

Zn- or Cu-containing CaP-Based Coatings Formed by Micro-Arc Oxidation on Titanium and Ti-40Nb Alloy: Part II-Wettability and Biological Performance.

This work describes the wettability and biological performance of Zn- and Cu-containing CaP-based coatings prepared by micro-arc oxidation on pure titanium (Ti) and novel Ti-40Nb alloy. Good hydrophilic properties of all the coatings were demonstrated by the low contact angles with liquids, not exceeding 45°. An increase in the applied voltage led to an increase of the coating roughness and porosity, thereby reducing the contact angles to 6° with water and to 17° with glycerol. The free surface energy of 75 ± 3 mJ/m2 for all the coatings were determined. Polar component was calculated as the main component of surface energy, caused by the presence of strong polar PO43- and OH- bonds. In vitro studies showed that low Cu and Zn amounts (~0.4 at.%) in the coatings promoted high motility of human adipose-derived multipotent mesenchymal stromal cells (hAMMSC) on the implant/cell interface and subsequent cell ability to differentiate into osteoblasts. In vivo study demonstrated 100% ectopic bone formation only on the surface of the CaP coating on Ti. The Zn- and Cu-containing CaP coatings on both substrates and the CaP coating on the Ti-40Nb alloy slightly decreased the incidence of ectopic osteogenesis down to 67%. The MAO coatings showed antibacterial efficacy against Staphylococcus aureus and can be arranged as follows: Zn-CaP/Ti > Cu-CaP/TiNb, Zn-CaP/TiNb > Cu-CaP/Ti.