In Vitro Molecular Study of Titanium-Niobium Alloy Biocompatibility

Abstract

Titanium dental implants have common clinical applications due to their biocompatibility, biophysical and biochemical characteristics. Although current titanium is thought to be safe and beneficial for patients, there are several indications that it may release toxic metal ions or metal nanoparticles from its alloys into the surrounding environment, which could lead to clinically relevant complications including toxic reactions as well as immune dysfunctions. Hence, an adequate selection and testing of medical biomaterial with outstanding properties are warranted. This study was designed to explore the biocompatibility of smooth titanium-niobium alloy (S_TiNb) versus smooth titanium commercially pure (S_TiCp)—a reference in implantology. All experiments were performed in vitro using human osteoblast-like SaOs-2 and monocyte THP-1 cell lines as models. Cell adhesion and growth morphology were determined by scanning electron microscopy, while cell viability was evaluated using WST-1 assay. Because niobate anions or niobium nanoparticles can be released from implants during biomaterial-cell interaction, potential immunotoxicity of potassium niobate (KNbO3) salt was evaluated by examining both metabolic activity and transcriptomic profiling of treated THP-1 monocytes. The main findings of this study are that S_TiCp and S_TiNb discs do not show an impact on the proliferation and viability of SaOs-2 cells compared to polystyrene surfaces, whereas a significant decrease in THP-1 cells’ viability and metabolic activity was observed in the presence of S_TiNb discs compared to the control group. However, no significant changes were found neeither at the metabolic activity nor at the transcriptomic level of THP-1 monocytes exposed to KNbO3 salt, suggesting that niobium has no effect on the immune system. Overall, these data imply a possible toxicity of S_TiNb discs toward THP-1 cells, which may not be directly related to niobium but perhaps to the manufacturing process of titanium- niobium alloy. Thus, this limitation must be overcome to make titanium alloy an excellent material for medical applications.

Enhanced antibacterial activity and superior biocompatibility of cobalt-deposited titanium discs for possible use in implant dentistry

“…Osteoblast cell cultures have been widely used to understand bone-biomaterial interactions. Different osteoblast cell lines, such as MG-63, SaOs-2, MC3T3-E1, and primary human osteoblasts, have been employed to study the effect of implant surface modification on their bioactivities 50 , 51 , 52 , 53 Figure 7 A shows the percentage cell viability of MG-63 cells on Ti and Co-deposited Ti samples after 24 h of culturing. A statistically significant difference in the cell viability was not observed between Ti and Co-deposited Ti samples indicating the excellent cytocompatibility of the Co-deposited surfaces.…”

In situ production of low-modulus Ti–Nb alloys by selective laser melting and their functional assessment toward orthopedic applications

“…Notably, the cell response to the alloys was marginally better on the Ti-Nb alloys than on the Ti64 control, especially on day 7, which is consistent with the literature suggesting that the Ti-Nb alloys exhibit excellent biocompatibility. [61][62][63] To further assess the toxicity of the Ti-based alloys, cell morphology was characterized, as compiled in Fig. 14.…”

“…While Ti is wellknown for its biocompatibility owing to its stable surface oxide layer, Nb has also been observed as a non-toxic element and is recognized for its utility in orthopedic applications. [61][62][63] Thus, cell studies on the additively manufactured Ti-Nb alloys confirm that the alloys are non-toxic and effectively support the attachment and proliferation of cells, thereby underscoring their promise as candidate biomaterials.…”

Titanium Implant Alloy Modified by Electrochemically Deposited Functional Bioactive Calcium Phosphate Coatings

“…However, the release of potentially harmful metal ions and their accumulation in body organs is of great concern, as vanadium is known for its cytotoxic effects, which can suppress cell growth and induce oxidative stress [10,11]. Therefore, Ti6Al7Nb alloy that contains less toxic, non-harmful Nb and meets the requirements for orthopaedic applications has been recently used [12][13][14]. These requirements include good biocompatibility, mechanical strength, stiffness, durability, corrosion resistance, and properties important for load-bearing applications (low elastic modulus and good fatigue resistance) [6,15,16].…”