M.U. Jurczyk

Nanoscale size effect in in situ titanium based composites with cell viability and cytocompatibility studies

Novel in situ Metal Matrix Nanocomposite (MMNC) materials based on titanium and boron, revealed their new properties in the nanoscale range. In situ nanocomposites, obtained through mechanical alloying and traditional powder metallurgy compaction and sintering, show obvious differences to their microstructural analogue. A unique microstructure connected with good mechanical properties reliant on the processing conditions favour the nanoscale range of results of the Ti-TiB in situ MMNC example. The data summarised in this work, support and extend the knowledge boundaries of the nanoscale size effect that influence not only the mechanical properties but also the studies on the cell viability and cytocompatibility. Prepared in the same bulk, in situ MMNC, based on titanium and boron, could be considered as a possible candidate for dental implants and other medical applications. The observed relations and research conclusions are transferable to the in situ MMNC material group. Aside from all the discussed relations, the increasing share of these composites in the ever-growing material markets, heavily depends on the attractiveness and a possible wider application of these composites as well as their operational simplicity presented in this work.

Antibacterial activity of nanostructured Ti–45S5 bioglass–Ag composite against Streptococcus mutans and Staphylococcus aureus

Mechanical alloying and annealing at 1150 °C for 2 h under an argon atmosphere were used to prepare Ti–45S5 bioglass nanocomposites. Ti–45S5 bioglass material was chemically modified by silver. The antibacterial activity of Ti–10% 45S5 bioglass nanocomposite containing silver against Streptococcus mutans and Staphylococcus aureus was studied. Nanocomposites were characterized by X-ray diffraction, scanning electron microscopy equipped with an electron energy dispersive spectrometer and transmission electron microscopy to evaluate phase composition, crystal structure and grain size. In vitro bacterial adhesion study indicated a significantly reduced number of Streptococcus mutans and Staphylococcus aureus on the bulk nanostructured Ti–45S5 bioglass–Ag plate surface in comparison to that on microcrystalline Ti plate surface. Nanostructured Ti-based biomaterials can be considered to be the future generation of dental implants.

In vitro biocompatibility of titanium after plasma surface alloying with boron.

Recently, the effect of different sizes of precursor powders during surface plasma alloying modification on the properties of titanium surface was studied. In this work we show in vitro test results of the titanium (α-Ti) after plasma surface alloying with boron (B). Ti-B nanopowders with 2 and 10wt% B were deposited onto microcrystalline Ti substrate. The in vitro cytocompatibility of these biomaterials was evaluated and compared with a conventional microcrystalline Ti. During the studies, established cell line of human gingival fibroblasts and osteoblasts were cultured in the presence of tested materials, and its survival rate and proliferation activity were examined. For this purpose, MTT assay, flow cytometric and fluorescent microscopic evaluation were made. Biocompatibility tests carried out indicate that the Ti after plasma surface alloying with B could be a possible candidate for dental implants and other medicinal applications. Plasma alloying is a promising method for improving the properties of titanium, thus increasing the field of its applications.

Development of β Type Ti23Mo-45S5 Bioglass Nanocomposites for Dental Applications

Titanium β-type alloys attract attention as biomaterials for dental applications. The aim of this work was the synthesis of nanostructured β type Ti23Mo-x wt % 45S5 Bioglass (x = 0, 3 and 10) composites by mechanical alloying and powder metallurgy methods and their characterization. The crystallization of the amorphous material upon annealing led to the formation of a nanostructured β type Ti23Mo alloy with a grain size of approximately 40 nm. With the increase of the 45S5 Bioglass contents in Ti23Mo, nanocomposite increase of the α-phase is noticeable. The electrochemical treatment in phosphoric acid electrolyte resulted in a porous surface, followed by bioactive ceramic Ca-P deposition. Corrosion resistance potentiodynamic testing in Ringer solution at 37 °C showed a positive effect of porosity and Ca-P deposition on nanostructured Ti23Mo 3 wt % 45S5 Bioglass nanocomposite. The contact angles of glycerol on the nanostructured Ti23Mo alloy were determined and show visible decrease for bulk Ti23Mo 3 wt % 45S5 Bioglass and etched Ti23Mo 3 wt % 45S5 Bioglass nanocomposites. In vitro tests culture of normal human osteoblast cells showed very good cell proliferation, colonization, and multilayering. The present study demonstrated that porous Ti23Mo 3 wt % 45S5 Bioglass nanocomposite is a promising biomaterial for bone tissue engineering.

Surface Modification of Pure Titanium by TiB Precipitation

Titanium and its alloys are common in medical implant applications because of their desirable properties, such as relatively low Young’s modulus, good fatigue strength, corrosion resistance, biocompatibility as well as formability and machinability. However, these materials cannot meet all of the clinical requirements. Current research focuses on improving not only the mechanical performance but mostly the biocompatibility of Ti-based systems through variations in alloy composition and surface treatment. One of the methods that allows the change of biological properties of Ti surface is the modification of its chemical composition. In this work plasma surface modification approach was used to improve mechanical properties by synthesis of composite layer structure on a pure titanium surface. The study aims at development of TiB precipitation dispersed uniformly at α-Ti matrix by plasma melting of Ti-2 wt% and Ti-10 wt% B alloy powders composition. Grain size of precursor powders obtained by mechanical alloying method and its homogenization can control the porosity and boron agglomeration tendency of the synthesized layers. Plasma procedure was taken under argon and helium inert atmosphere and surface was obtained by single passage of plasma pillar upon the prepared surface. The Vickers microhardness of obtained surface reached nearly 850HV, which was much higher compared with initial sample of the pure titanium substrate of 160HV. The surface corrosion resistance in 0.9% NaCl solution was nearly the same as for pure titanium, showing stable behaviour of created oxide layer, with no negative effect of dual phase microstructure. In vitro biocompatibility test in static condition was performed. All samples showed good cell growth. Our studies suggests that chemical composition of modified titanium surface by TiB precipitation by plasma alloying process has no negative effect on cytocompatibility.

Osteoblast Behaviour on Nanostructured Ti-Bioceramic Composites

Ti and Ti-based alloys are preferred materials in the production of implants in both medical and dental applications. One of the methods that allow the change of biological properties of Ti alloys is the modification of their chemical composition and microstructure. In this study, new biocompatible, nanostructured Ti-x vol% SiO2, Ti-x vol% 45S5 Bioglass, and Ti-x vol% HAp (x=0, 3, 10) materials have been developed, manufactured and studied in terms of their biocompatibility. These materials give the possibility of controlling in detail the grain structure and the composition of the alloy and, consequently, the mechanical and biocompatibility performances. Our results of in vitro studies show that these bionanocomposites have excellent biocompatibility and could integrate with bone. After 1st day of incubation cells show good adhesion to the surface of studied samples in the form of filopodia. After 5 days of incubation, the typical monolayer was observed. With regard to microcrystalline Ti it could help to obtain better dental implants with better mechanical properties and corrosion resistance.

Properties of ultrafine-grained Mg-based composites modified by addition of silver and hydroxyapatite

ABSTRACT In this study, hydroxyapatite and silver were added to Mg–1Zn–1Mn–0.3Zr alloy to fabricate ultrafine-grained metal matrix composites. Grain sizes of approximately 85 nm were recorded by atomic force microscopy for the Mg–1Zn–1Mn–0.3Zr–5 wt-% HA–1 wt-% Ag composite. The contact angles in water and simulated body fluid on the ultrafine-grained Mg–1Zn–1Mn–0.3Zr-based composites were determined. Following a hydrofluoric acid treatment, the surface wettability changed from hydrophilicity to hydrophobicity. The electrochemical test showed that the corrosion resistance of the fluoride-treated specimens was higher, when compared with the untreated samples. The Mg–1Zn–1Mn–0.3Zr–5 wt-% HA and Mg–1Zn–1Mn–0.3Zr–5 wt-% of HA–1 wt-% Ag composites modified with MgF2 have a higher degree of biocompatibility, which makes them potential candidates for medical applications

Molecular analysis of biocompatibility of anodized titanium with deposited silver nanodendrites

Titanium (>99.6% purity) and its anodically oxidized modifications, with and without deposited silver nanodendrites regarding its biocompatibility were evaluated. In human gingival fibroblasts and osteoblast cell lines grown on tested samples, the level of expression of genes encoding αV (ITGAV) and β1 (ITGB1) integrin subunits also genes encoding focal adhesion (FAK) and extracellular-signal regulated (ERK) kinases was assessed. For this purpose, the qualitative and quantitative PCR technique was used. The expression of studied genes was dependent on the origin of cell lines and the type of evaluated material. The high expression of PBGD and ITGAV genes in fibroblasts grown on the surface of anodically modified titanium with deposited silver nanodendrites indicates potentially high biocompatibility of these samples for soft tissue cells. The high expression of the ITGB1 and ERK1 genes and the enhanced expression of the FAK gene in osteoblasts cells grown on the tested material was also observed. Summarizing, the nanocrystalline Ti modified with silver deposits showed higher biocompatibility in comparison with the conventional pure Ti samples.