Ihwanul Aziz

Background The growing demand for tooth replacement has increased the use of Ti dental implants the long-term success of which depends on stable osseointegration. However, this process can be compromised by bacterial biofilm formation on implant surfaces. To overcome this, a coating strategy was explored that combines magnesium—known for its bone-regenerative and antibacterial properties—in the form of nano-Mg(OH)2 with gelatin to slow magnesium degradation and support bone growth. This study evaluated the in vitro osteogenic potential and antibacterial activity of nano-Mg(OH)2–gelatin as coating material for Ti dental implant. Methodology Pure Ti plates (1×1 cm) were coated via electrospinning for in vitro evaluation. Samples were divided into four groups: 0 (control), 4, 6, and 8% nano-Mg(OH)₂-gelatin coating. Coating morphology and thickness were analyzed using SEM. Mg ion release, pH, and surface hydrophilicity (contact angle) were measured. Biological assessments included MC3T3-E1 cell proliferation, alkaline phosphatase (ALP) activity, and antibacterial activity against Streptococcus mutans and Streptococcus sanguinis. Statistical analyses were performed using one- or two-way ANOVA (p=0.05). The optimal biologically compatible concentration of Mg(OH)2 was evaluated. Result SEM revealed a uniform, spiderweb-like coating with ~110–120 µm thickness. The coatings showed an initial burst of Mg ion release, peaking at 24 hours, followed by a gradual decline up to 240 hours. Increasing Mg content enhanced surface hydrophilicity, with the 6% group showing optimal wettability. Increasing Mg content improved MC3T3-E1 cell proliferation, peaking at 8%, whereas ALP activity was enhanced in the 6% group. Moreover, the observed decrease in S. mutans and S. sanguinis colonies suggests the 6% concentration showed balance performance as coating. Conclusion The nano-Mg(OH)₂-gelatin coating, particularly at 6% concentration, significantly enhanced the bioactivity of the Ti surface, showing dual-functional activity in vitro.

Incorporating silver (Ag) into titanium nitride (TiN) coatings is an effective strategy to enhance their structural integrity, mechanical strength, surface characteristics, and antibacterial activity. In this study, Ti–Ag–N coatings were deposited via DC magnetron sputtering using Ag plates with diameters of 0, 4, 6, and 8 mm. The resulting films were analyzed using XRD, SEM/EDS, hardness tests, and water contact angle measurements, while their antibacterial performance was tested against Staphylococcus aureus. Moderate Ag incorporation (Ag-6) yielded the best overall properties, improving crystallinity, producing a uniform Ag distribution, and increasing surface energy. This composition also demonstrated the highest hardness (179.24 VHN) and excellent wettability. Antibacterial tests confirmed that Ag-containing coatings - particularly Ag-6 - suppressed bacterial growth by up to 99.99%, mainly due to controlled Ag ion release and enhanced surface energy. These results indicate that optimizing Ag content effectively balances durability, functionality, and antibacterial performance, making Ti–Ag–N coatings promising candidates for biomedical and advanced engineering applications. HIGHLIGHTS Ti-Ag-N thin films were prepared by DC sputtering. Varying Ag content modified the crystallographic structure and surface energy. Increased Ag incorporation enhanced surface hydrophilicity. Antibacterial tests showed up to 99.99% inhibition against S. aureus. A strong link was found between structure, wettability, and antibacterial performance. GRAPHICAL ABSTRACT

The object of this study is Fe-Cr-Mn stainless steel alloys containing 0.23–0.41 wt.% C and 17.59–18.36 wt.% Cr with varying Mn content. The development of nickel-free stainless steels addresses the drawbacks of conventional implant materials such as titanium alloys, Co-Cr alloys, and AISI 316L stainless steel, which often suffer from biocompatibility issues, toxicity, and mechanical incompatibility with bone. The Fe-Cr-Mn alloys were produced by high-frequency induction melting and subsequently tested for microstructure, mechanical, wear, and corrosion properties. SEM-EDS revealed a transition from ferritic structure (2.5% Mn) to duplex α+γ (5% Mn) and predominantly austenitic structure (7.5% Mn). Mechanical testing showed that hardness and tensile strength peaked at 2.5% Mn, while ductility and impact toughness improved with increasing Mn, reaching their highest values at 5% Mn. Wear resistance increased significantly at higher Mn levels due to the formation of stable tribo-oxides and the strengthening effect of the austenitic matrix. Electrochemical testing in 0.9% NaCl solution showed that Fe-18Cr-5Mn possessed the best corrosion resistance, attributed to the stability of its passive film, while excessive Mn (7.5%) caused passivation breakdown through Mn-hydroxide formation. Overall, Fe-18Cr-5Mn exhibited the best synergy between strength, toughness, wear resistance, and corrosion protection under physiological saline conditions, establishing it as a promising nickel-free stainless steel for next-generation biomedical implant materials

The object of this study is to combine the properties of Mn and the advantages of Fe-Cr-C to improve biomaterial compatible characteristics. Three alloys of Fe-Cr-C with compositions of 12 wt. % Mn, 16 wt. % Mn, and 20 wt. % Mn, were investigated. Microstructural analysis was carried out using a scanning electron microscope (SEM), and a Vickers hardness test kit was used to evaluate the hardness. The pin-on-disc method was used for the dry slide wear test, and the corrosion test was carried out using the three-electrode cell polarization method. The hardness value of Fe-Cr-C alloy increased by 28.7 % with the increase of Mn content from 12 wt. % (231.8 VHN) to 20 wt. % (298.4 VHN). The tensile strength value increased by 30.3 % with an increase in Mn content from 12 wt. % (522.69 MPa) to 20 wt. % (680.89 MPa), while the strain value decreased by 30.9 %. However, impact toughness did somewhat decline, from 0.213 J/mm2 at 12 wt. % Mn to 0.169 J/mm2 at 20 wt. % Mn. The wear rate results for Fe-Cr-C 20 wt. % Mn 0.000156 mm3/kg. show a reduction of more than 15 wt. % when compared to Fe-Cr-C 12 wt. % Mn because of an increase in the hard-intermetallic area. Additionally, corrosion resistance improved significantly, with the corrosion rate decreasing from 0.005814 mm/yr at 12 wt. % Mn to 0.001780 mm/yr at 20 wt. % Mn, demonstrating that higher Mn content reduces material degradation in corrosive environments. Based on the experimental results, Fe-Cr-C 20 wt % Mn alloy has the highest mechanical and corrosion resistance of the three types of alloys. Fe-Cr-C with high Mn alloys are promising candidates for application as biomaterials for bone implants by optimizing the Mn content and corrosion resistance

Traumatic, osteoarthritic, tumoral, and congenital bone issues impact human lives and health. The next generation of bone implants is made from biodegradable materials, including Fe-based materials with superior mechanical properties and high biocompatibility. However, efforts to inhibit the risk of inflammation and bacterial infection due to the biological response and corrosion properties of metals are a significant challenge. This study aims to develop biomaterials based on Fe-Cr-Mn alloys to obtain superior physical and mechanical properties through plasma nitriding. Each sample was plasma-nitridated in a vacuum chamber at various temperatures of 250–450 °C for 3 hours at a pressure of 1.8 kPa. Several main tests were performed to investigate the effects of plasma nitriding, such as the chemical compositions of raw material, surface nitrogen contents, phase changes, thickness, hardness, and corrosion. Those parameters were then used to evaluate plasma nitriding's effectiveness, including observing the change in phenomena at each temperature treatment. The results indicated that forming the S phase on the surface of Fe-13.8Cr-8.9Mn alloy is a saturated solution of nitrogen in ɣ-Fe, where the nitrogen content on the surface increases with increasing nitriding temperature. The layer's surface hardness is uniform across its whole thickness, which reduces as the grade of raw material passes through the nitride layer. The highest hardness at a nitriding temperature of 450 °C reached 625.3 VHN. The findings showed that the corrosion rate decreased significantly, reaching the lowest value, 0.0018 mm/year, at a plasma nitriding temperature of 450 °C. Plasma nitriding could enhance the physical and mechanical properties of Fe-Cr-Mn alloy

The cylinder liner is a tube that protects the piston and is a place for the combustion process. The combustion process causes continuous friction to make the cylinder liner wear out. Therefore the cylinder liner must be made of materials that have high hardness. To obtain a high hardness level, surface treatment with DC sputtering techniques is carried out. Surface treatment with DC sputtering technique for 120 minutes with variations of Argon gas and Nitrogen gas 70:30, 80:20, and 90:10. Based on the XRD test results, all treated samples contained a WN layer. The crystal structure of the raw material samples is hexagonal, and the crystal structure of all processed samples is cubic. Vickers hardness characterization shows that the raw material is 110.93 HV. While the sample treated with Ar70:N30 was 234.66 HV. The optimum hardness occurred in samples treated with Ar80:N20 with a hardness of 311.87 HV. However, the Ar90:N10 treatment experienced a decrease in hardness to 130.44 HV. Based on the results of thin film testing, WN affects the increase in the hardness of the cylinder liner material. This is evidenced by the increase in hardness in samples coated with WN.

The fabrication of silver (Ag) and gold (Au) thin film electrodes was successfully carried out using the DC sputtering deposition method. These thin film electrodes were able to detect the increase in serum albumin concentration that was used as a prognostic factor for leukemia. The simulation and the optical experimental analysis show that an increase in BSA concentration can increase the absorbance peak observed at a wavelength of 435 nm on hypoalbumin medium and 470 nm on normal concentration of serum albumin medium. The performance of the electrodes was electrochemically tested, in which it was shown that a decrease in oxidation and reduction peaks occurred with respect to an increase in BSA concentration. An oxidation peak was observed at a voltage of 0.5 V for the Ag thin film. For the Au, Au/Ag, and Ag/Au thin films, an oxidation peak was observed at a voltage of 1.0 V. The limits of detection (LODs) of the Ag, Ag/Au, Au, and Au/Ag thin films were 0.56, 0.24, 0.64, and 0.36 g/dL, respectively. Therefore, based on both the electrochemical and optical analysis, the Ag/Au thin film possessed the highest potential for prognosis monitoring of leukemia compared with the other Ag and Au thin films.

The fabrication of a ZnO/Au nanosquare-array electrode was successfully carried out for the detection of glucose concentration in biomedical applications. The fabrication of the ZnO/Au nanosquare array using an ultra-thin alumina mask (UTAM) based on the imprinted anodic aluminum oxide (AAO) template and the direct current (DC) sputtering method was able to produce a very well-ordered nanosquare arrangement with a side size of 300 nm and a thickness of 100 nm. Tests were done to evaluate the performance of the electrode by means of cyclic voltammetry (CV) which showed that the addition of glucose oxidase (GOx) increased the sensitivity of the electrode up to 1180 ± 116 μA mM⁻¹cm⁻², compared with its sensitivity prior to the addition of GOx of 188.34 ± 18.70 mA mM⁻¹ cm⁻². A i_ox/i_red ratio equal to ~1 between the peaks of redox reactions was obtained for high (hyperglycemia), normal, and low (hypoglycemia) levels of glucose. The ZnO/Au nanosquare-array electrode was 7.54% more sensitive than the ZnO/Au thin-film electrode. Furthermore, finite-difference time-domain (FDTD) simulations and theoretical calculations of the energy density of the electric and magnetic fields produced by the ZnO/Au electrode were carried out and compared to the results of CV. From the results of CV, FDTD simulation, and theoretical calculations, it was confirmed that the ZnO/Au nanosquare array possessed a significant optical absorption and that the quantum effect from the nanosquare array resulted in a higher sensitivity than the thin film.

The development of silver (Ag) thin films and the fabrication of Ag nanosquare arrays with the use of an anodic aluminum oxide (AAO) template and leaf extracts were successfully carried out using the DC sputtering and spin coating deposition methods. Ag thin films and Ag nanosquare arrays are developed to monitor cancer prognosis due to the correlation between serum albumin levels and prognostic factors, as well as the binding of serum albumin to the surface of these electrodes. Nanosquare structures were fabricated using AAO templates with varying diameters and a gap distance between adjacent unit cells of 100 nm. The nanosquare array with a diameter of 250 nm and irradiated with electromagnetic waves with a wavelength of around 800 nm possessed the greatest electric field distribution compared to the other variations of diameters and wavelengths. The results of the absorption measurement and simulation showed a greater shift in absorption peak wavelength when carried out using the Ag nanosquare array. The absorption peak wavelengths of the Ag nanosquare array in normal blood and blood with cancer lymphocytes were 700–774 nm and 800–850 nm, respectively. The electrochemical test showed that the sensitivity values of the Ag thin-film electrode deposited using DC sputtering, the Ag thin-film electrode deposited using spin coating, and the Ag nanosquare array in detecting PBS+BSA concentration in the cyclic voltammetry (CV) experiment were 1.308 µA mM⁻¹cm⁻², 0.022 µA mM⁻¹cm⁻², and 39.917 µA mM⁻¹cm⁻², respectively. Meanwhile, the sensitivity values of the Ag thin film and the Ag nanosquare array in detecting the PBS+BSA concentration in the electrochemical impedance spectroscopy (EIS) measurement were 6593.76 Ohm·cm²/mM and 69,000 Ohm·cm²/mM, respectively. Thus, our analysis of the optical and electrochemical characteristics of Ag thin films and Ag nanosquare arrays showed that both can be used as an alternative biomedical technology to monitor the prognosis of blood cancer based on the concentration of serum albumin in blood.