A review on in vitro/in vivo response of additively manufactured Ti-6Al-4V alloy.

Bone replacement using porous and solid metallic implants, such as Ti-alloy implants, is regarded as one of the most practical therapeutic approaches in biomedical engineering. The bone is a complex tissue with various mechanical properties based on the site of action. Patient-specific Ti-6Al-4V constructs may address the key needs in bone treatment for having customized implants that mimic the complex structure of the natural tissue and diminish the risk of implant failure. This review focuses on the most promising methods of fabricating such patient-specific Ti-6Al-4V implants using additive manufacturing (AM) with a specific emphasis on the popular subcategory, which is powder bed fusion (PBF). Characteristics of the ideal implant to promote optimized tissue-implant interactions, as well as physical, mechanical/chemical treatments and modifications will be discussed. Accordingly, such investigations will be classified into 3B-based approaches (Biofunctionality, Bioactivity, and Biostability), which mainly govern native body response and ultimately the success in implantation.

Nitinol: From historical milestones to functional properties and biomedical applications.

Isoatomic NiTi alloy (Nitinol) has become an important biomaterial due to its unique characteristics, including shape memory effect, superelasticity, and high damping. Nitinol has been widely used in the biomedical field, including orthopedics, vascular stents, orthodontics, and other medical devices. However, there have been convicting views about the biocompatibility of Nitinol. Some studies have shown that Nitinol has extremely low cytotoxicity, indicating Nitinol has good biocompatibility. However, some studies have shown that the in-vivo corrosion resistance of Nitinol significantly decreases. This comprehensive paper discusses the historical developments of Nitinol, its biomedical applications, and its specific functional property. These render the suitability of Nitinol for such biomedical applications and provide insights into its in vivo and in vitro biocompatibility in the physiological environment and the antimicrobial strategies that can be applied to enhance its biocompatibility. Although 3D metal printing is still immature and Nitinol medical materials are difficult to be processed, Nitinol biomaterials have excellent potential and commercial value for 3D printing. However, there are still significant problems in the processing of Nitinol and improving its biocompatibility. With the deepening of research and continuous progress in surface modification and coating technology, a series of medical devices made from Nitinol are expected to be released soon.

A state-of-the-art review of the fabrication and characteristics of titanium and its alloys for biomedical applications.

Abstract: Commercially pure titanium and titanium alloys have been among the most commonly used materials for biomedical applications since the 1950s. Due to the excellent mechanical tribological properties, corrosion resistance, biocompatibility, and antibacterial properties of titanium, it is getting much attention as a biomaterial for implants. Furthermore, titanium promotes osseointegration without any additional adhesives by physically bonding with the living bone at the implant site. These properties are crucial for producing high-strength metallic alloys for biomedical applications. Titanium alloys are manufactured into the three types of α, ß, and α + ß. The scientific and clinical understanding of titanium and its potential applications, especially in the biomedical field, are still in the early stages. This review aims to establish a credible platform for the current and future roles of titanium in biomedicine. We first explore the developmental history of titanium. Then, we review the recent advancement of the utility of titanium in diverse biomedical areas, its functional properties, mechanisms of biocompatibility, host tissue responses, and various relevant antimicrobial strategies. Future research will be directed toward advanced manufacturing technologies, such as powder-based additive manufacturing, electron beam melting and laser melting deposition, as well as analyzing the effects of alloying elements on the biocompatibility, corrosion resistance, and mechanical properties of titanium. Moreover, the role of titania nanotubes in regenerative medicine and nanomedicine applications, such as localized drug delivery system, immunomodulatory agents, antibacterial agents, and hemocompatibility, is investigated, and the paper concludes with the future outlook of titanium alloys as biomaterials.

Computational study of H2S adsorption on the pristine and transitional metal-doped phosphorene.

This study aimed to investigate the H2S molecule adsorption on the pristine and X-doped phosphorene (X = first-row transition metal) using DFT+U method. The doping of X atoms on the phosphorene has been evaluated from energetic and electronics aspects. The binding energy values and the results of projected density of states (PDOS) analysis revealed that Ti-, V-, Fe-, and Sc-doped phosphorene have more capability to adsorb H2S molecule in comparison with other systems. Moreover, the cohesive energy values showed that these (Ti, V, Fe, and Sc) doped surfaces are also energetically feasible.