Design and preparation of Ti-xFe antibacterial titanium alloys based on micro-area potential difference

Fe was selected as an alloying element for the first time to prepare a new antibacterial titanium alloy based on micro-area potential difference (MAPD) antibacterial mechanism. The microstructure, the corrosion resistance, the mechanical properties, the antibacterial properties and the cell biocompatibility have been investigated in detail by optical microscopy, scanning electron microscopy, electrochemical testing, mechanical property test, plate count method and cell toxicity measurement. It was demonstrated that heat treatment had a significant on the compressive mechanical properties and the antibacterial properties. Ti-xFe (x = 3,5 and 9) alloys after 850 °C/3 h + 550 °C/62 h heat treatment exhibited strong antimicrobial properties with an antibacterial rate of more than 90% due to the MAPD caused by the redistribution of Fe element during the aging process. In addition, the Fe content and the heat treatment process had a significant influence on the mechanical properties of Ti-xFe alloy but had nearly no effect on the corrosion resistance. All Ti-xFe alloys showed non-toxicity to the MC3T3 cell line in comparison with cp-Ti, indicating that the microzone potential difference had no adverse effect on the corrosion resistance, cell proliferation, adhesion, and spreading. Strong antibacterial properties, good cell compatibility and good corrosion resistance demonstrated that Ti-xFe alloy might be a candidate titanium alloy for medical applications.

Ti-30Nb-3Ag alloy with improved corrosion resistance and antibacterial properties for orthopedic and dental applications produced by mechanical alloying

Titanium alloys have gained popularity as a bioimplant material due to their biocompatibility, low modulus of elasticity, and increased strength. However, other issues, such as corrosion resistance, and infections can reduce the implant's lifespan. This paper aims to fabricate a new Ti-30Nb-3Ag at% alloy with enhanced in vitro corrosion and antibacterial properties by mechanical alloying (MA) followed by powder consolidation. XRD, SEM/EDX, and Vickers microhardness analyses were used to examine the phases compositions, microstructure, and microhardness, respectively. The in vitro corrosion performance of Ti-30Nb-3Ag alloy was inspected in a simulated body medium and artificial saliva. The alloy's antibacterial properties were evaluated in the gram-positive and negative bacterial medium. The results showed that after MA for 60 h, nanocrystalline β-Ti (BCC) and α-Ti (HCP) solid solutions were formed with crystallite sizes of 7.44 and 3.47 nm, respectively. The sintered sample exhibited densifications of 97%, with a microstructure composed of β-Ti, α-Ti, and a minor quantity of ultrafine Ti₂Ag phase. The microhardness result showed that Ti-30Nb-3Ag alloy possesses HV 491.5. Ti-30Nb-3Ag alloy has a potent antibacterial capability of 85.75% and 88.81% relative to Ti-6Al-4V alloy and CP-Ti, respectively. In vitro corrosion results revealed that the Ti-30Nb-3Ag alloy exhibited the widespread passive area in the investigated anodic regions and presented the highest impedance values in comparison with the commercial alloys, confirming its improved corrosion resistance performance in both studied mediums. Ti-30Nb-3Ag alloy possibly be a competitive bioimplant material for orthopedic and dental uses owing to its enhanced biocorrosion and antibacterial properties compared to commercial Ti-6Al-4V alloy and CP-Ti.

Feasibility study on Ti-15Mo-7Cu with low elastic modulus and high antibacterial property

Titanium and titanium alloy with low density, high specific strength, good biological, excellent mechanical compatibility and easy to process have been widely used in the medical materials, but their application in orthopedics and dentistry often face bacterial infection, corrosion failure and stress shielding. In this paper, Ti-15Mo-7Cu (TM-7Cu) alloy was prepared by high vacuum non-consumable electric arc melting furnace and then treated by solution and aging treatment. The microstructure, mechanical properties, antibacterial properties and cytocompatibility were studied by X-ray diffraction, microhardness tester, electrochemical working station, antibacterial test and Live/Dead staining technology. The results have shown that the heat treatment significantly influenced the phase transformation, the precipitation of Ti₂Cu phase, the elastic modulus and the antibacterial ability. With the extension of the aging time, the elastic modulus slightly increased and the antibacterial rate obviously increased. TM-7Cu alloy with a low elastic modulus of 83GPa and a high antibacterial rate of > 93% was obtained. TM-7Cu alloy showed no cytotoxicity to MC3T3. It was suggested that TM-7Cu might be a highly competitive medical material.

Development of a low elastic modulus and antibacterial Ti-13Nb-13Zr-5Cu titanium alloy by microstructure controlling

In order to prepare a titanium with a low elastic modulus and good antibacterial property to meet the requirements as a biomedical material, Ti-13Nb-13Zr-5Cu (TNZ-5Cu) alloy was prepared by high vacuum consume electric arc melting furnace and then subjected to a solution treatment at 950 °C followed by a short-term aging treatment at 600 °C, for 15 min, 30 min, 1 h and 2 h, respectively. The microstructure, mechanical property, antibacterial property and biocompatibility of TNZ-5Cu were investigated in detail. The research results have shown that the solid solution treated alloy was mainly composed of β-phase and α″-phase, while the aged alloys of β-phase, α″-phase, α-phase and Ti₂Cu. Compared with Ti-13Nb-13Zr alloy (65 GPa) and Ti-6Al-4 V alloy (111 GPa), the elastic modulus of TNZ-5Cu alloy after solution treatment was about 72 GPa and increased with the aging treatment up to 85 GPa, and the hardness was maintained at a higher level than that of Ti-13Nb-13Zr alloys (288 HV). The bacteria plate count results showed that the antibacterial ability of TNZ-5Cu alloy increased with the extension of the aging duration from <60% at 15-30 min to >90% at 1-2 h. Cell experiments showed that all TNZ-5Cu alloy had good cell compatibility. The low modulus and the antibacterial property could provide potential to avoid stress shield and device-related inflection in the clinical application.

Antibacterial metals and alloys for potential biomedical implants

Metals and alloys, including stainless steel, titanium and its alloys, cobalt alloys, and other metals and alloys have been widely used clinically as implant materials, but implant-related infection or inflammation is still one of the main causes of implantation failure. The bacterial infection or inflammation that seriously threatens human health has already become a worldwide complaint. Antibacterial metals and alloys recently have attracted wide attention for their long-term stable antibacterial ability, good mechanical properties and good biocompatibility in vitro and in vivo. In this review, common antibacterial alloying elements, antibacterial standards and testing methods were introduced. Recent developments in the design and manufacturing of antibacterial metal alloys containing various antibacterial agents were described in detail, including antibacterial stainless steel, antibacterial titanium alloy, antibacterial zinc and alloy, antibacterial magnesium and alloy, antibacterial cobalt alloy, and other antibacterial metals and alloys. Researches on the antibacterial properties, mechanical properties, corrosion resistance and biocompatibility of antibacterial metals and alloys have been summarized in detail for the first time. It is hoped that this review could help researchers understand the development of antibacterial alloys in a timely manner, thereby could promote the development of antibacterial metal alloys and the clinical application.

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This paper focuses the recent development of several antibacterial metals and alloys as biomedical materials.

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The possible antibacterial mechanisms of antibacterial metals and alloys are summarized in this paper.

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This review discusses the feasibility of antibacterial metals and alloys as biomedical implants in the future.