Çomaklı, O.; Acar, M.T.; Yazıcı, M.; Arslan, E.; Türkez, H.

Ti6Al4V alloys were fabricated using a selective laser melting (SLM) method at different energy densities. Afterward, TiO2 nanotube (TNT) films were deposited on the surfaces of these substrates via anodization to investigate the effect of energy density on the resulting TNT structures. According to results, the high-energy–density SLM sample exhibited a relative density (RD) exceeding 98.8%, representing the highest RD among all the fabricated samples. Moreover, the smallest nanotube diameter and the greatest film thickness were obtained from the anodization of the substrate with the highest relative density, which was a result of being fabricated at the highest energy density. Electrochemical tests revealed significant improvements in corrosion resistance for TNT-coated samples compared to untreated Ti6Al4V. The TNT-coated Ti6Al4V sample fabricated at the highest SLM energy density (A2) exhibited the highest corrosion potential (Ecorr = −1.24 V) and the lowest corrosion current density (Icorr = 56 × 10⁻⁸ A/cm2), while untreated Ti6Al4V (A1) showed Ecorr = −1.74 V and Icorr = 303 × 10⁻⁷ A/cm2. Biological evaluations demonstrated that TiO₂ nanotube (TNT) coatings significantly enhanced the biocompatibility and antibacterial properties of Ti6Al4V surfaces, particularly for the A2 sample. Fluorescence staining, MTT assays, and nuclear staining confirmed that A2, which featured reduced nanotube diameter and increased length, supported superior osteoblast adhesion, proliferation, and viability, while also exhibiting the strongest antibacterial activity against E. coli. These improvements were attributed to the optimized nanotopography, which promoted cell interaction and inhibited bacterial adhesion.

Çomaklı, Onur; Meletlioğlu, Emrah; Sadeler, Furkan; Çakır, Mevra Aslan

This study investigates the tribological performance, antimicrobial properties, and cytotoxicity of Ti15Mo alloys coated with TiN and TiCN via physical vapor deposition (PVD). The alloys were subjected to a two-body wear test in distilled water, simulating 2 years of clinical use in a chewing simulator. The wear testing demonstrated a significant reduction in wear volume loss for both TiN and TiCN coatings compared to the uncoated Ti15Mo substrate. TiCN exhibited superior wear resistance, as evidenced by lower friction coefficients and minimal wear damage. X-ray diffraction and X-ray photoelectron spectroscopy validated the achieved coating of compact, homogeneous coatings. Scanning electron microscopy images revealed columnar microstructures with an approximate thickness of 2.5 µm. Antibacterial assays indicated a notable reduction in bacterial adherence and growth on the coated surfaces, with TiCN displaying the most significant antibacterial performance against Staphylococcus aureus and Escherichia coli. Cytotoxicity was assessed through MTT assays, showing that TiN and TiCN coatings exhibited high biocompatibility, with cell viability above 70%. These findings demonstrate that TiN and TiCN coatings significantly enhance the wear resistance, antibacterial performance, and biocompatibility of Ti15Mo alloys, positioning them as viable candidates for advanced biomedical applications.

Çıbıkçı, Kübra Çağla; Yaman, Mustafa

Hybrid foams are a type of composite material created by combining two foam materials. They are preferred in many applications due to their lightweight, high strength, and ability to absorb more energy. In this research, a new hybrid foam was designed for use in sandwich cores of structural materials. The hybrid foam was formed by combining closed-cell aluminum foam and expanded polystyrene (EPS)-filled syntactic foam. The EPS-filled syntactic foams were produced with the conventional mold casting technique. Uniaxial compressive behaviors (0.5 mm/min) of layered hybrid foams consisting of EPS-filled syntactic foam with three different densities and closed-cell aluminum foam were investigated experimentally and compared with conventional single-foamed materials. These results exhibited that in general, layered hybrid foams outperform conventional single-foamed materials in terms of compressive strength. Moreover, the natural frequency and damping ratio of the layered hybrid foams were investigated by vibration tests under clamped-free and free-free boundary conditions and compared to conventional single-foamed materials. It was established that the vibration damping capacity of the layered hybrid foams improved compared to the closed-cell aluminum foam. Additionally, the microstructure of the conventional single-foamed materials was examined by SEM. In the outcome of the research, the experimental results showed that layered hybrid foam provides an opportunity to design lightweight cellular materials with effective mechanical properties.

Can, Musa Mutlu; Shawuti, Shalima; Kalindemirtas, Ferdane Danisman; Erdemir, Gokce; Kuruca, Durdane Serap; Kaneko, Satoru; Aktas, Zerrin; Oncul, Oral

The following acknowledgment was omitted from the original article: ‘‘The authors thank A. R. Sherwani for technical assistance with sample preparation during his work as a Ph.D. student.’’

Can, Musa Mutlu; Shawuti, Shalima; Kalindemirtas, Ferdane Danisman; Erdemir, Gokce; Kuruca, Durdane Serap; Kaneko, Satoru; Aktas, Zerrin; Oncul, Oral

The study was based on surface functionalization of conductive PANI (polyaniline) polymer for drug delivery systems. Specifically, an electrochemical polymerization technique was performed for the synthesis of PANI layers on tin-doped indium oxide (In2O3:Sn or ITO)-coated PET (polyethylene terephthalate) substrates. Three main factors were studied: binding ability, drug-loading ability and drug-delivering ability. PANI layers, combined with active carbon (AC), were organized as biomaterials to carry the anticancer drug doxorubicin (DOX). Two different films, PANI and PANI with AC, were polymerized in the emeraldine salt form of PANI. A comparison of the two samples proved that AC molecules enabled DOX molecules to bind to the PANI surface, as observed by the UV–Vis absorption spectra of the films. DOX molecules were detected by UV–Vis spectra with an absorption peak at 547 nm. Findings from drug loading/release tests and in vitro cytotoxicity results confirm that these films can be used as drug delivery systems. This work underlines essential role of AC in the PANI layer for drug delivery.

Surucu, G.; Colakoglu, K.; Deligoz, E.; Ciftci, Y.; Korozlu, N.

The structural, elastic, electronic and optical properties of Zn 1-xMgxSe ternary mixed crystals are investigated by utilizing the first-principles plane-wave pseudopotential method within the LDA approximations. Some basic physical properties, such as lattice constant, bulk modulus, second-order elastic constants (Cij), Shear modulus, Young's modulus, Poison's ratio, Lamé constants and the electronic band structures, are calculated. We have, also, predicted the optical properties such as dielectric functions, refractive index and energy loss function of these ternary mixed crystals. Our results agree well with the available data in the literature.