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Biodegradable 3D-printed polycaprolactone scaffolds for bone tissue engineering applications have been extensively studied as they can provide an attractive porous architecture mimicking natural bone, with tunable physical and mechanical properties enhancing positive cellular response. The main drawbacks of polycaprolactone-based scaffolds, limiting their applications in tissue engineering are: their hydrophobic nature, low bioactivity and poor mechanical properties compared to native bone tissue. To overcome these issues, the surface of scaffolds is usually modified and covered with a ceramic layer. However, a detailed description of the adhesion forces of ceramic particles to the polymer surface of the scaffolds is still lacking. Our present work is focused on obtaining PCL-based composite scaffolds to strengthen the architecture of the final product. In this manuscript, we report qualitative and quantitative evaluation of low temperature plasma modification followed by detailed studies of the adhesion forces between chemically attached ceramic layer and the surface of polycaprolactone-nanohydroxyapatite composite 3D-printed scaffolds. The results suggest modification-dependent alteration of the internal structure and morphology, as well as mechanical and physical scaffold properties recorded with atomic force microscopy. Moreover, changes in the material surface were followed by enhanced adhesion forces binding the ceramic layer to polymer-based scaffolds.

In the technological process of manufacturing, distribution and recycling of nanoparticles, is easy to spread them in the air. The respiratory system is the primary target for inhaled NPs. The authors discuss the influence of the complexing compounds used in the “button up” synthesis of inorganic nanoparticles, on the cells activity during in vitro studies. We decided to examine the impact of yttrium aluminum borates (YAB) nanoparticles doped with ytterbium ions synthesized from various polymeric precursors on the viability of human bronchial epithelial cells using the WST-8 assay, depending on the concentrations of these nanoparticles. The optically active YAB:Yb3+ nanoparticles were obtained by the sol–gel method. In our experiments three various hydrophilic polysaccharides and two different acids were used as polymeric complexing agents. Luminescent materials may be utilised in various fields, including medical diagnostic, however YAB:Yb3+ NPs are considered to be harmful or inert. We have tested those particles to determine the way their shape influences biological response. We show the effect of NPs suspension in biological media and their behavior under physiological conditions. In our work we demonstrate the influence of polymeric agents on the viability of bronchial cells, and consequently, on the probably inflammatory response. In the present study we report, that mannitol with citric acid favours the formation of fibrous particles while others polymeric agents, as salicylic acid with sorbitol favour spherical shape formation. Cellular responses to fibrous particles are different from these to spherical ones because bio-persistent fibers induce multiplication and possibility to obtain inflammasome. Particles in fiber form trigger the inflammation process, and thus can cause cell multiplication effect. We determined whether the polymeric precursors can have impact on the activation of the surface of NPs, and if they trigger interactions of NPs with cells. It turns out, that the issue of the toxicity of nanoparticles is very complex and should be approached comprehensively. Our results confirmed that stability, agglomeration, cytotoxicity of NPs and the multiplication of cells, depend on polymeric agents used in sol–gel synthesis. It had been shown that the method of nanoparticles synthesis has a significant impact on cellular viability and multiplication of cells. Preliminary studies on human bronchial cell demonstrated that the high viability and proliferation depends on the polymer precursors used in synthesis process. To describe the structure of the obtained NPs the following methods were used: Scanning Electron Microscopy, Transmission Electron Microscopy, Atomic Forces Microscopy, X-ray diffraction and Raman Spectroscopy.

Composite scaffolds of bioactive glass (SiO2-CaO) and bioresorbable polyesters: poly-l-lactic acid (PLLA) and polycaprolactone (PCL) were produced by polymer coating of porous foams. Their structure and mechanical properties were investigated in micro and nanoscale, by the means of scanning electron microscopy, PeakForce Quantitative Nanomechanical Property Mapping (PF-QNM) atomic force microscopy, micro-computed tomography and contact angle measurements. This is one of the first studies in which the nanomechanical properties (elastic modulus, adhesion) were measured and mapped simultaneously with topography imaging (PF-QNM AFM) for bioactive glass and bioactive glass - polymer coated scaffolds. Our findings show that polymer coated scaffolds had higher average roughness and lower stiffness in comparison to pure bioactive glass scaffolds. Such coating-dependent scaffold properties may promote different cells-scaffold interaction.

Bioactive glass-based scaffolds are commonly used in bone tissue engineering due to their biocompatibility, mechanical strength and adequate porous structure. However, their hydrophobicity and brittleness limits their practical application. In this study, to improve nanomechanical properties of such scaffolds, pure bioactive hybrid glass and two bioactive hybrid glass-polymer coated composites were fabricated. A complementary micro and nanoscale characterization techniques (SEM, AFM, μCT, FTIR, compressive test, goniometer) were implemented for detailed description of architecture and physicochemical properties of hybrid bioactive glass-based scaffolds with emphasis on nano-mechanics. The final step was in-vitro evaluation of three dimensional macroporous structures. Our findings show that after polymer addition, architecture, topography and surface properties of the scaffolds were changed and promoted favoured behaviour of the cells.

Holmium-doped monoclinic KGd(WO4)2 nanoparticles were synthesized by the mechano-chemical method. The structure and morphology of KGW:Ho 10 at.% nanopowders were investigated with the use of X-ray Powder Diffraction, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Emission and excitation spectra of KGW nanocrystals were also measured using a fluorometer with a xenon lamp and OPO laser source. The influence of nanoparticles of KGW doped with 10 at.% of holmium on the viability of J774.1 mouse BALB/c monocyte macrophage cells was tested by the WST8 assay. Preliminary immunity cell studies demonstrated a high viability of KGW:Ho 10 at%. Hence, these nanoparticles are promising for imaging applications. To characterize and quantify the physical stability of the nanoparticles of KGW:Ho 10 at.% suitable for biomedical applications, nanoparticles of KGW:Ho in the range of 80–200 nm were prepared.

For the first time an orthorhombic bismuth zinc borate (Bi 2 ZnB 2 O 7 , BZBO) with noncentrosymmetric structure was synthesized by means of modified Pechini method. This approach allowed to reduce both the duration and temperature of the procedure in comparison to conventional solid state synthesis of desirable compounds in form of polycrystalline powders. Selected RE 3+ dopants were successfully introduced into BZBO matrix using this method. The obtained materials were studied and crystallographic calculations were performed in order to confirm the structure of as-prepared polycrystals. Morphology of obtained powders was investigated using Atomic Force Microscopy. Energy Dispersive X-Ray Spectroscopy measurements were done in order to proceed chemical microanalysis. Second Harmonic Generation measurements showed strong effect of incorporated RE 3+ ions on the increasing second order nonlinear optical response of BZBO:RE 3+ powders.

Collagen fibril/(calcium phosphate and carbonate) composite coatings on 316L stainless steel were developed with a cathodic deposition technique. The response of SaOS-2 osteoblast-like cells to the collagen/calcium salt-coated 316L steel was investigated. The collagen fibrils were self-assembled on the 316L steel surface and immobilized by their partial incorporation into a calcium salt layer electrodeposited cathodically in Hanks’ solution. The amount of calcium salt depended on the applied cathodic potential. The mineralization of collagen fibrils was observed. The collagen coverage localized and the composition of calcium salts varied on the same specimen. Such non-uniform surfaces affected the cell response. The observed outlines of cell bodies and nuclei on the thin collagen coating were clearer than those on the thick collagen coating in most cases. The collagen coating did not significantly influence the mean viability of cells on the whole specimen surface. Interestingly, the alkaline phosphatase activity per cell on the collagen/calcium salt-coated specimens was higher than that on the as-received specimen. It was revealed that cathodic deposition is an effective technique to immobilize collagen fibrils on a 316L steel surface.

Nanocrystalline cobalt was carburised with ethylene in the range 340– 500°C to obtain Co(C) nanocapsules. The carbon deposit was reduced by a flow of hydrogen in the range 500– 560°C. The reduction kinetics were studied using thermogravimetry, described by the equation: α = Α[1-exp(-kt)n]. The apparent activation energy of the reduction process of the carbon deposit was determined. After carburisation and reduction the samples were examined by XRD and HRTEM.

Bacteria living constantly in the oral cavity are in the form of a biofilm. The biofilm formed on a solid base such as the enamel of the teeth, fillings, restorations, orthodontic appliances or obturators is dental plaque. Disturbance of homeostasis of biofilm, excessive growth or increase in the number of acid-forming bacteria leads to the development of the most common diseases of the oral cavity, i.e. dental caries and periodontal disease. The presence of bacterial biofilm on the walls of the root canal or at the top of the root on an outer wall leads to complications and failure in endodontic treatment. The aim of the study was to present the latest information on the occurrence, development and the role of biofilm in the etiopathogenesis of oral diseases and its control. Based on the literature analyzed, it can be concluded that the biofilm, due to its complex structure and numerous mechanisms of bacteria adaptation, is an effective barrier against the traditional agents with antibacterial properties. There are now great hopes for nanotechnology as an innovative method for obtaining new structures of nanometric size and different properties than source materials. The use of antibacterial properties of nano-silver used in dentistry significantly reduces the metabolic activity and the number of colony forming bacteria and lactic acid production in the biofilm.

The hydrogen influence on the microstructure of the austenitic-ferritic Cr22-Ni5-Mo3 stainless steel was investigated. Cathodic hydrogen charging was performed electrochemically from aqueous solution of 0.1M H2SO4 with hydrogen entry promoter addition. The aim of this study was to reveal microstructural changes appearing during the hydrogen charging and particularly to clarify the occurrence of phase transformations induced by hydrogen. The specific changes in both phases of steel were observed. In the ferritic phase, strong increase of dislocation density was noticed. Longer time of hydrogen charging leaded also to the strips and twin plates formation in ferrite phase. In the austenitic phase, the generation of stacking faults, followed by the formation of α' martensite was remarked.

The processing method of anisotropic Nd-Fe-B magnets, based on rapid solidification of a molten alloy, followed by hot pressing and die-upset forging is currently well established and commonly used for the processing of high performance magnets. In this method uniaxial stress, created in an isotropic, polycrystalline alloy, leads to texture formation with the crystallographic c axis, of the tetragonal structure in each grain, being parallel, to the deformation direction (DD). However, the mechanisms leading to the anisotropic structure and accompanying processes are still not fully understood. In this study the Fe 73.7 Nd 13.6 Co 6.6 Ga 0.6 B 5.5 alloy, after rapid solidification by melt spinning and hot pressing was subjected to die-upset forging with strains 30% and 65%, respectively. Systematic studies of the structure, microstructure and magnetic domain structure versus processing parameters were performed for this alloy, using magnetic measurements, transmission electron microscopy and atomic force microscopy.

Microstructural changes occurring in austenitic–ferritic stainless steel after two variants of thermo-mechanical treatment and subjected to cathodic hydrogen charging were studied using atomic force microscopy operated in the magnetic force imaging mode. Hydrogen-induced phase transformations were observed to occur in both steel variants. In austenite, they were manifested by the formation of α ′ martensite magnetic laths. In ferrite, the microstructural changes resulted in a pronounced surface relief being formed.

An Al2O3/Ni-P composite was formed by hot pressing of alumina powder, coated with chemically plated nano Ni-P. The powders were consolidated at room temperature, 600 and 1000oC. The consolidated specimens were studied by SEM, TEM/HRTM, MFM (magnetic force microscopy) and tested or hardness. It was found that the fabrication method results in a structure of interpenetrating phases of high electric conductivity and that samples consolidated at room temperature and sintered at 600oC retain the nanometric grain size of the metallic phase. Hardness measurements are discussed in terms of the fabrication temperature and structure of the composites.

The paper presents the results obtained on nanometric austenitic stainless steel processed by High Pressure Torsion (HPT)[1-2]. The aim of the project was to investigate properties of the oxide layers formed on the material subjected to Severe Plastic Deformation (SPD) in comparison to standard micrometer grain size specimens. Therefore AFM investigations have been carried out on the specimens surfaces subjected to HPT and the subsequent surface cleaning and exposure to ambient air. TEM studies of the substrate and measurements of trybological properties have also been made. The results of all these experiments are discussed in terms of the characteristics of nanosized austenitic stainless steels.

The formation of novel carbon nanostructures containing Fe-Nd-B nanocrystallites is reported. Tests were performed in a DC arc plasma reactor under He atmosphere using (Fe-Nd-B)- filled anodes. The influence of the operational parameters pressure and anode composition on the product morphology was studied. The products were analyzed by HR TEM, MFM and magnetic measurements. Emission spectroscopy was performed to determine the temperature and C2 radical distribution in the arc.