This study investigates the influence of mineral fillers on the hydrolytic stability and mechanical durability of polylactide (PLA) composites under accelerated aqueous ageing conditions. Composites containing halloysite nanotubes (HNT) and bentonite-based fillers (BM, BS, BSP) at 2 wt.% were prepared using a powder-coating and injection moulding approach. Accelerated hydrolytic degradation was conducted at 50 °C for up to six weeks. The degradation behaviour was evaluated through mass variation, water absorption, incubation medium analysis (pH and electrical conductivity), mechanical testing, surface observations, and contact angle measurements. The results revealed a clear filler-dependent response. Bentonite-filled composites exhibited increased water absorption and accelerated mass loss, which may be associated with the hydrophilic and layered structure of smectite clays facilitating moisture transport. In contrast, halloysite-filled composites showed comparatively reduced water uptake and improved short-term mechanical performance. Analysis of incubation media indicated decreasing pH and increasing conductivity, reflecting the formation of acidic degradation products and the release of ionic species. A qualitative correlation between moisture uptake and deterioration of mechanical properties was observed, particularly for bentonite-containing systems. Microstructural observations demonstrated the presence of surface roughening, microcracks, and heterogeneous degradation features, which may be linked to non-uniform filler dispersion and localised stress concentrations. Contact angle measurements confirmed ageing-induced surface hydrophilisation, although these results should be treated as indirect indicators of surface physicochemical changes. Overall, the results suggest that filler morphology, in combination with hydrophilicity and dispersion state, influences moisture transport and degradation behaviour in PLA composites. The findings contribute to understanding structure–property–degradation relationships in PLA-based systems and indicate that mineral filler selection may be considered as a strategy for tailoring material performance in moisture-exposed applications.
In this study, the properties of electrophoretically deposited (EPD) coatings on orthodontic implants made from Ti-6Al-4V alloy were evaluated during simulated implantation trials on animal bones. Three types of chitosan-based coatings were prepared using EPD: titanium nitride microparticles (TiNPs), titanium nitride nanoparticles (TiNNPs), and boron nitride particles (BNPs). Each of these coatings was also modified by adding a polylactic acid (PLA) layer using a dip-coating technique to compare their properties with and without this additional layer. The coatings were analysed using optical microscopy, confocal microscopy, and scanning electron microscopy (SEM) with elemental analysis. Surface roughness measurements of the coated implants were also conducted to highlight differences that could significantly influence the type and strength of the bone-implant interface, directly affecting the stability of the implant as an anchorage unit. Eventually, to evaluate the antibacterial properties of the EPD coatings, their antibacterial activity against both Gram-positive and Gram-negative bacteria strains was tested. Scanning electron observations confirmed the homogenous distribution of micro- and nanoparticles in all coatings. The highest surface roughness values were observed in layers containing titanium nitride nanoparticles (TiNNPs) and chitosan. The presence of an additional dip-coating PLA layer improved the adhesion, and its effect on the surface roughness depended on the particle size. While the antibacterial properties of the coatings show promising results, achieving optimal adhesion of the coatings to implants remains a challenge that requires further development.
The paper presents the results of research on the possibility of obtaining, in a single-firing process, multi-layer glazes with a high degree of gloss and antibacterial properties imparted by introducing silver nanoparticles (AgNPs) both before firing and into the impregnation applied to the glaze after firing. All research and technological operations were verified during tests performed directly on the technological lines in the industrial plant, and the produced glazes were tested for antibacterial properties in accordance with ISO 22196:2011 and JIS Z 2801 standards. Antibacterial properties were assessed immediately after production, and the selected glazes were also tested for the stability of these properties over time by examining the influence of strong detergents, HCl acid and KOH base, as well as abrasion processes on the ability to act against bacteria. To additionally assess the durability of the obtained antibacterial coatings depending on the degree of surface degradation, the roughness of the glazes was also monitored. Measurements of the size distribution of AgNPs introduced into glazes and impregnants, SEM microscopic observations with EDS analysis of the glaze surface, as well as their basic rheological properties were also carried out. The applied technological approach indicates that the presence of AgNPs in glazes can cause the expected effect provided that the particles are dispersed in the glaze in a controlled manner, with the best effects of the intended antibacterial action being obtained through synergistic volumetric and surface modification, i.e. impregnation of glazes. It has also been proven that the obtained antibacterial properties of glazes are stable over time and are not weakened by aggressive factors such as: acidic or alkaline environment, strong detergents or mechanical damage through abrasion.
The microbiocidal properties of zinc, in both elemental and oxide forms, are well established. In this study, nanometric ZnO layers with a thickness of 40-150 nm were deposited on glass substrates using the sol-gel dip-coating method. The coatings were prepared by 3 or 6 dipping cycles, followed by a thermal treatment at 773 K for 1 h. Two thermal treatment schemes were applied: annealing after each immersion (x) and single annealing after all immersions (x & lowast;). Structural and morphological characterization showed, that the sequence of annealing strongly influenced a zinc oxide crystallite size: 18-28 nm for the coatings annealed after each immersion and 10-13 nm for the coatings annealed once. The spectroscopic ellipsometry confirmed uniformity of the films and revealed that a bacterial biofilm thickness on uncoated glass reached 100-120 nm, while the presence of ZnO layers significantly reduced this to 70-80 nm for Escherichia coli and 20-40 nm for Staphylococcus aureus, independently of the preparation route. Antibacterial testing demonstrated that the coatings annealed after each immersion (3x, 6x) achieved higher reduction of E. coli (13 % for 3x and 60 % for 6x respectively), whereas the coatings annealed once (3x & lowast;, 6x & lowast;) were more effective against S. aureus, with the strongest effect observed for 6x & lowast; (99 % bacteria reduction). Ion-release studies indicated, that in a hydrated environment, the coatings subjected to the single-step annealing released more Zn2+ ions (3.25-4.25 ppm) compared to the multi-step annealed films (<4.25 ppm after 24 h incubation), which correlated with their higher antibacterial activity against S. aureus. Qualitative observations further confirmed, that the presence of crystallites of varying size affects roughness and wettability, which, together with ion release and ROS generation, governs the bactericidal response. Importantly, all ZnO coatings reduced the biofilm formation while maintaining high optical transparency (90 % transmittance), highlighting their potential for applications in touchscreens, packaging, and photovoltaic devices.
The aim of the study was to develop hybrid nanomaterials based on monodisperse silica spheres as carriers for silver nanoparticles (AgNPs) or bismuth nanoparticles (BiNPs) and to evaluate their antimicrobial properties. Silica spheres were synthesized using a modified Stöber method, either unmodified or functionalized with (3-aminopropyl)triethoxysilane (APTES), prior to AgNP or BiNP deposition. The materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES), and zeta potential measurements, while antimicrobial activity was assessed by microdilution against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), with Helicobacter pylori as a clinical model. The results show that both SiO2-AgNP and SiO2-BiNP composites completely inhibited H. pylori and showed high activity against other pathogens, although P. aeruginosa remained less susceptible. Functionalization of AgNP-coated samples with APTES promoted uniform distribution of AgNPs, with the minimum bactericidal concentration (MBC) to minimum inhibitory concentration (MIC) ratios ranging from 1 to 4, confirming a bactericidal rather than bacteriostatic effect. In contrast, BiNP-coated samples without APTES exhibited lower MIC values from 74 to 595 μg mL−1, consistent with increased Bi3+ release from amorphous phases. This indicates the antimicrobial potential, highlighting the role of surface functionalization in regulating ion release and biological performance, and suggesting applications in the biomedical and food industries.
The study examined the possibility of intercalation of montmorillonite with neomycin in an aqueous drug solution and the factors influencing the effectiveness of this process, such as the ion exchange capacity and process conditions, including the time and temperature of incubation with the drug. X-ray diffractometry (XRD), infrared spectroscopy (FTIR), thermal analysis (DSC/TG), and Zeta potential measurement were used to confirm drug intercalation as well as to investigate the nature of clay–drug interactions. The obtained conjugates with the most favorable physicochemical properties were also tested for antibacterial response against Gram-negative bacteria (Escherichia coli) to confirm that the bactericidal properties of neomycin were retained after intercalation and UV–VIS spectrophotometry was used to examine the kinetics of drug release from the carrier. The results of the conducted research clearly indicate the successful intercalation of neomycin in montmorillonite and indicate the influence of process parameters on the properties of not only the conjugates themselves but also the properties of the intercalated drug, particularly its bactericidal activity. Ultimately, a temperature of 50 °C was found to be optimal for effective drug intercalation and the conjugates obtained within 2 h showed the highest antibacterial activity, indicating the highest potential of the thus-obtained montmorillonite conjugates as neomycin carriers.
The aim of the work was to examine the possibility of using modified halloysite nanotubes as a gentamicin carrier and to determine the usefulness of the modification in terms of the effect on the amount of the drug attached, its release time, but also on the biocidal properties of the carriers. In order to fully examine the halloysite in terms of the possibility of gentamicin incorporating, a number of modifications of the native halloysite were carried out prior to gentamicin intercalation with the use of sodium alkali, sulfuric and phosphoric acids, curcumin and the process of delamination of nanotubes (expanded halloysite) with ammonium persulfate in sulfuric acid. Gentamicin was added to unmodified and modified halloysite in an amount corresponding to the cation exchange capacity of pure halloysite from the Polish Dunino deposit, which was the reference sample for all modified carriers. The obtained materials were tested to determine the effect of surface modification and their interaction with the introduced antibiotic on the biological activity of the carrier, kinetics of drug release, as well as on the antibacterial activity against Escherichia coli Gram-negative bacteria (reference strain). For all materials, structural changes were examined using infrared spectroscopy (FTIR) and X-ray diffraction (XRD); thermal differential scanning calorimetry with thermogravimetric analysis (DSC/TG) was performed as well. The samples were also observed for morphological changes after modification and drug activation by transmission electron microscopy (TEM). The conducted tests clearly show that all samples of halloysite intercalated with gentamicin showed high antibacterial activity, with the highest antibacterial activity for the sample modified with sodium hydroxide and intercalated with the drug. It was found that the type of halloysite surface modification has a significant effect on the amount of gentamicin intercalated and then released into the surrounding environment but does not significantly affect its ability to further influence drug release over time. The highest amount of drug released among all intercalated samples was recorded for halloysite modified with ammonium persulfate (real loading efficiency above 11%), for which high antibacterial activity was found after surface modification, before drug intercalation. It is also worth noting that intrinsic antibacterial activity was found for non-drug-intercalated materials after surface functionalization with phosphoric acid (V) and ammonium persulfate in the presence of sulfuric acid (V).
Electrospinning is an increasingly popular technique for obtaining scaffolds for skin regeneration. However, electrospun scaffolds may also have some disadvantages, as the densely packed fibers in the scaffold structure can limit the penetration of skin cells into the inner part of the material. Such a dense arrangement of fibers can cause the cells to treat the 3D material as 2D one, and thus cause them to accumulate only on the upper surface. In this study, bi-polymer scaffolds made of polylactide (PLA) and polyvinyl alcohol (PVA) electrospun in a sequential or a concurrent system were investigated in a different PLA:PVA ratio (2:1 and 1:1). The properties of six types of model materials were investigated and compared i.e.; the initial materials electrospun by the sequential (PLA/PVA, 2PLA/PVA) and the concurrent system (PLA||PVA) and the same materials with removed PVA fibers (PLA/rPVA, 2PLA/rPVA, PLA||rPVA). The fiber models were intended to increase the porosity and coherent structure parameters of the scaffolds. The applied treatment involving the removal of PVA nanofibers increased the size of interfibrous pores formed between the PLA fibers. Ultimately, the porosity of the PLA/PVA scaffolds increased from 78 % to 99 %, and the time of water absorption decreased from 516 to 2 s. The change in wettability was induced by a synergistic effect of decrease in roughness after washing out and the presence of residual PVA fibers. The chemical analysis carried out confirmed the presence of PVA residues on the PLA fibers (FTIR-ATR study). In vitro studies were performed on human keratinocytes (HaKaT) and macrophages (RAW264.7), for which penetration into the inner part of the PLAIIPVA scaffold was observed. The new proposed approach, which allows the removal of PVA fibers from the bicomponent material, allows to obtain a scaffold with increased porosity, and thus better permeability for cells and nutrients.
A study was conducted on selected nanoclay fillers, i.e. montmorillonite (MMT) or halloysite (HNT) in polylactic acid (PLA) pellets for the manufacture of filaments for 3D printing. A 1-3 weight fraction of the filler was used. In order to compatibilize the nanofiller with the PLA, two methods were employed to facilitate dispersion of the nanoclay particles: using prewetting of the nanoclay in dichloromethane (DCM) and introducing a short-chain plasticizer (polyethylene glycol, PEG200) during the homogenization process. The effectiveness of filler dispersion was verified by performing thermal analy-sis, i.e. thermogravimetry and differential scanning calorimetry (DG/DSC), as well as by microscopic observations. The processability of the obtained nanocomposite filament was verified for the finished products manufactured from both of the materials by FDM printing. Mechanical strength and impact tests were conducted on the printed samples. The results showed that the prints made from the nanocomposite filaments have better tensile strength (by 25 and 10% for PLA/HNT and PLA/MMT, respectively) compared to prints made from the pure polymer filament.
The paper presents the results of research on the influence of the granulometric composition on the rheological properties of granulates from soft waste produced in the manufacturing of ceramic tiles using the Lamgea and Continua methods in terms of the possibility of their reuse. The composition of the granulates was modified by removing individual grain fractions in three measurement series. Comparatively, the measurement samples for the production granulates were prepared in the same way. Microscopic observations and granulometric analysis showed significant differences in the grain shape and grain size distribution of granulates. The soft waste granulates also showed much worse flow ability than the production granulates. It was shown that the removal of the smallest fractions significantly improved the rheological properties of soft waste granulates. This tendency was also observed in the case of measurements of changes in the bulk density. A Brookfield powder analyzer was used for rheological tests, and a flow analysis was performed using the numerical Jenike classification.
The paper presents the results of research on the influence of the chemical composition of frits on the microstructure and mechanical properties of ceramic glazes. Glaze sets are designed based on frits of different chemical composition and increasing B2O3 content. Thermal DSC analysis showed a high tendency to crystallize the designed glazes, and in the obtained glazes the main crystalline phases were diopside or anorthite, which was also confirmed by XRD analysis and SEM microscopic observations. In glazes not containing B2O3 and at a SiO2/ Al2O3 molar ratio in the 5.3-5.6 range, mainly diopside crystallized, while a decrease in the SiO2/Al2O3 molar ratio to a value below 4.9 and an increase in B2O3 content contributed to an increase in the anorthite crystal phase content. The obtained glazes were characterized by a surface roughness of Ra in the range of 0.2-1.1 mu m and a high abrasion resistance measured with a mass loss of less than 50 mg after 6000 abrasion cycles in accordance with the EN ISO 10545-7 standard. Such high abrasion resistance was achieved thanks to the high hardness of the glazes in the range of 6.4-8.0 GPa, which was confirmed by the Vickers hardness measurement.
The development of new chemically resistant anodes for protonic ceramic fuel cells (PCFCs) is urgently required to avoid the costly deep hydrogen purification method. Ba0.95Ca0.05Ce0.9Y0.1O3−δ (5CBCY), which is more chemically resistant than BaCaCe0.9Y0.1O3−δ, was here tested as a component of a composite NiO–5CBCY anode material. A preparation slurry comprising 5CBCY, NiO, graphite, and an organic medium was tape cast, sintered and subjected to thermal treatment in 10 vol.% H2 in Ar at 700 °C. Differential thermal analysis, thermogravimetry, quadrupole mass spectrometry, X-ray diffraction analysis, scanning electron microscopy, the AC four-probe method and electrochemical impedance spectroscopy were used for the investigation. The electrical conductivity of the Ni–5CBCY in H2–Ar at 700 °C was 1.1 S/cm. In the same gas atmosphere but with an additional 5 vol.% CO2, it was slightly lower, at 0.8 S/cm. The Ni–5CBCY cermet exhibited repeatable electrical conductivity values during Ni-to-NiO oxidation cycles and NiO-to-Ni reduction in the 5CBCY matrix, making it sufficient for preliminary testing in PCFCs.
In this study, we propose a new approach in the anterior cruciate ligament (ACL) replacement to provide stability and integration with bone tunnel. A polylactide (PLA)-based tubular implant was used to support the graft stabilization in femoral and tibial bones and to stimulate the healing process after (ACL) replacement on a sheep model. The ACL was replaced with an autologous Achilles tendon split graft. The tendon-to-bone healing in the model was analyzed after 6 and 12 weeks. Two groups of animals were compared, i.e. the group with the PLAbased implant used in the ACL replacement and the control group without the implant. The knee joints were mechanically and clinically evaluated, including the histopathology tests, to determine their stability and integrity. The results indicated that the bioresorbable PLA-based tubular implant may facilitate integration of the tendon graft with bone. Remodeling the allograft inside the implant improves the joint mobility from the first week of healing: no pathological changes were observed at the surgery site and in the animals' mobility. After 6 and 12 weeks of healing no significant changes in the mechanical parameters of the knee joint were observed, regarding the joint failure force, knee displacement, angular mobility range and joint stiffness. Relatively small values of the non-destructive tests in the knee displacement, already 6 weeks after surgery, indicated the early stabilization of the knee joint. The studies showed that the failure forces of knee joints after the ACL replacement with the PLA-based implant are lower than those of an intact joint, although their biomechanical features, including strain-at- failure, are similar. The biomechanical parameters of the knee joint were significantly improved due to the selected method of attaching the autograft ends to the femoral and tibial bone surfaces. After 12 weeks the intra-tunnel tendon-bone site with the PLA implant revealed the better tibia-femur joint mechanical stability, linear force-strain function and the decreasing strain-to-failure value, as compared to the control group.
Emulsion electrospinning is a method of modifying a fibers’ surface and functional properties by encapsulation of the bioactive molecules. In our studies, bovine serum albumin (BSA) played the role of the modifier, and to protect the protein during the electrospinning process, the W/O (water-in-oil) emulsions were prepared, consisting of polymer and micelles formed from BSA and anionic (sodium dodecyl sulfate–S) or nonionic (Tween 80–T) surfactant. It was found that the micelle size distribution was strongly dependent on the nature and the amount of the surfactant, indicating that a higher concentration of the surfactant results in a higher tendency to form smaller micelles (4–9 µm for S and 8–13 µm for T). The appearance of anionic surfactant micelles reduced the diameter of the fiber (100–700 nm) and the wettability of the nonwoven surface (up to 77°) compared to un-modified PCL polymer fibers (100–900 nm and 130°). The use of a non-ionic surfactant resulted in better loading efficiency of micelles with albumin (about 90%), lower wettability of the nonwoven fabric (about 25°) and the formation of larger fibers (100–1100 nm). X-ray photoelectron spectroscopy (XPS) was used to detect the presence of the protein, and UV-Vis spectrophotometry was used to determine the loading efficiency and the nature of the release. The results showed that the location of the micelles influenced the release profiles of the protein, and the materials modified with micelles with the nonionic surfactant showed no burst release. The release kinetics was characteristic of the zero-order release model compared to anionic surfactants. The selected surfactant concentrations did not adversely affect the biological properties of fibrous substrates, such as high viability and low cytotoxicity of RAW macrophages 264.7.
Electrospinning was used to obtain multifunctional fibrous composite materials with a matrix of poly-ɛ-caprolactone (PCL) and 2 wt.% addition of a nanofiller: montmorillonite (MMT), montmorillonite intercalated with gentamicin sulphate (MMTG) or gentamicin sulphate (G). In the first stage, the aluminosilicate gallery was modified by introducing gentamicin sulfate into it, and the effectiveness of the intercalation process was confirmed on the basis of changes in the clay particle size from 0.5 µm (for MMT) to 0.8 µm (for MMTG), an increase in the interplanar distance d001 from 12.3 Å (for MMT) to 13.9 Å (for MMTG) and altered clay grain morphology. In the second part of the experiment, the electrospinning process was carried out in which the polymer nonwovens with and without the modifier were prepared directly from dichloromethane (DCM) and N,N-dimethylformamide (DMF). The nanocomposite fibrous membranes containing montmorillonite were prepared from the same polymer solution but after homogenization with the modifier (13 wt.%). The degree of dispersion of the modifier was evaluated by average microarray analysis from observed area (EDS), which was also used to determine the intercalation of montmorillonite with gentamicin sulfate. An increase in the size of the fibers was found for the materials with the presence of the modifier, with the largest diameters measured for PCL_MMT (625 nm), and the smaller ones for PCL_MMTG (578 nm) and PCL_G (512 nm). The dispersion of MMT and MMTG in the PCL fibers was also confirmed by indirect studies such as change in mechanical properties of the nonwovens membrane, where the neat PCL nonwoven was used as a reference material. The addition of the modifier reduced the contact angle of PCL nonwovens (from 120° for PCL to 96° for PCL_G and 98° for PCL_MMTG). An approximately 10% increase in tensile strength of the nonwoven fabric with the addition of MMT compared to the neat PCL nonwoven fabric was also observed. The results of microbiological tests showed antibacterial activity of all obtained materials; however, the inhibition zones were the highest for the materials containing gentamicin sulphate, and the release time of the active substance was significantly extended for the materials with the addition of montmorillonite containing the antibiotic. The results clearly show that the electrospinning technique can be effectively used to obtain nanobiocomposite fibers with the addition of nonintercalated and intercalated montmorillonite with improved strength and increased stiffness compared to materials made only of the polymer fibers, provided that a high filler dispersion in the spinning solution is obtained.
The aim of this work was to study effect of the type of silica nanoparticles on the properties of nanocomposites for application in the guided bone regeneration (GBR). Two types of nanometric silica particles with different size, morphology and specific surface area (SSA) i.e., high specific surface silica (hss-SiO2) and low specific surface silica (lss-SiO2), were used as nano-fillers for a resorbable polymer matrix: poly(L-lactide-co-D,L-lactide), called PLDLA. It was shown that higher surface specific area and morphology (including pore size distribution) recorded for hss-SiO2 influences chemical activity of the nanoparticle; in addition, hydroxyl groups appeared on the surface. The nanoparticle with 10 times lower specific surface area (lss-SiO2) characterized lower chemical action. In addition, a lack of hydroxyl groups on the surface obstructed apatite nucleation (reduced zeta potential in comparison to hss-SiO2), where an apatite layer appeared already after 48 h of incubation in the simulated body fluid (SBF), and no significant changes in crystallinity of PLDLA/lss-SiO2 nanocomposite material in comparison to neat PLDLA foil were observed. The presence and type of inorganic particles in the PLDLA matrix influenced various physicochemical properties such as the wettability, and the roughness parameter note for PLDLA/lss-SiO2 increased. The results of biological investigation show that the bioactive nanocomposites with hss-SiO2 may stimulate osteoblast and fibroblast cells'proliferation and secretion of collagen type I. Additionally, both nanocomposites with the nanometric silica inducted differentiation of mesenchymal cells into osteoblasts at a proliferation stage in in vitro conditions. A higher concentration of alkaline phosphatase (ALP) was observed on the material modified with hss-SiO2 silica.
The comprehensive results regarding the physicochemical properties of carbonaceous materials that are obtained from pistachio shells support their usage as solid fuels to supply direct carbon solid oxide fuel cells (DC-SOFCs). The influence of preparation conditions on variations in the chemical composition, morphology of the biochar powders, and degree of graphitization of carbonaceous materials were investigated. Based on structural investigations (X-ray diffraction analysis and Raman spectroscopy), it was observed that disordered carbon particles developed during the application of thermal treatments. The use of X-ray fluorescence enabled a comparative analysis of the chemical composition of the inorganic matter in biocarbon-based samples. Additionally, the gasification of carbonaceous-based samples vs. time at a temperature of 850 °C was investigated in a H2O or CO2 gas atmosphere. The analysis demonstrated the conversion rate of biochar obtained from pistachio shells to H2, CH4 and CO during steam gasification. The electrochemical investigations of the DC-SOFCs that were supplied with biochars obtained from pistachio shells were characterized by satisfactory values for the current and power densities at a temperature range of 700–850 °C. However, a higher power output of the DC-SOFCs was observed when CO2 was introduced to the anode chamber. Therefore, the impact of the Boudouard reaction on the performance of DC-SOFCs was confirmed. The chars that were prepared from pistachio shells were adequate for solid fuels for utilization in DC–SOFCs.
The effect of the BaO addition on the microstructure and structure of the glasses from the K2O-MgO-CaO-Al2O3-SiO2-(BaO) system was investigated in this study. The results were obtained by testing the crystallization capability of the glasses during the fast-firing cycle. Thermal analysis proved a high tendency to crystallize the tested glasses/frits. X-ray analysis showed the presence of diopside and anorthite as the main crystalline phases in all glazes obtained from the tested glasses. Microscopic observations showed that barium oxide introduced in the range of 0.4-2.1 mol% into the examined system strongly influences the number and size of crystalline phases. The introduction of 2.1 mol% BaO into the composition also resulted in crystallization of celsian. The thermal characteristic of the glasses was carried out using differential scanning calorimetry (DSC) and the crystalline phases were determined by X-ray diffractometry. The glaze microstructure was investigated by scanning (SEM) and transmission electron (TEM)microscopy. Additional information on the structure of frits was derived from mid-infrared (MIR) and Raman spectroscopy. (C) 2020 Published by Elsevier B.V.
The extracellular matrix (ECM) can be a convenient scaffold used in tissue engineering, regenerative medicine and pharmacy. The synthetic cell matrix should imitate the natural extracellular matrix in both composition and architecture. The study examined fibrous chitosan modified with fragments of human collagen I (10–15 amino acids) mimicking the internal sphere of native protein. The surface of chitosan fibers was modified by physical and chemical methods to obtain polysaccharide-peptide conjugates, which may be considered analogous to the complex of glycosaminoglycans (GAG) and peptides present in the cell matrix. The surface of fibrous chitosan was enriched with fragments of human collagen I, using physicochemical properties (water absorption during electrospraying) and chemical compatibility (activity of amide and peptide groups) during synthesis. The method of modification had an effect on changing the diameter of the fibers and their topography, as assessed by means of a scanning electron microscopy (SEM). The presence of peptides on the surface of the fibers was confirmed by spectroscopic studies (FTIR-ATR and FT Raman). It has been shown that the chemical modification provided a homogeneous distribution of the peptide on the fiber, without changing its morphology as opposed to the physical modification of the fiber, which is visible on the surface in the form of peptide aggregates. The biocompatibility of the materials thus obtained was confirmed during biological studies using MG-63 osteoblast-like cells. Correct morphology observed after 3 days of culture (live-dead test) confirmed the suitability of the substrates for biomedical applications.