In-vivo evaluation of molybdenum as bioabsorbable stent candidate

The biocompatibility and degradation behavior of pure molybdenum (Mo) as a bioresorbable metallic material (BMM) for implant applications were investigated. In vitro degradation of a commercially available Mo wire (ø250 µm) was examined after immersion in modified Kokubo’s SBF for 28 days at 37 °C and pH 7.4. For assessment of in vivo degradation, the Mo wire was implanted into the abdominal aorta of female Wistar rats for 3, 6 and 12 months. Microstructure and corrosion behavior were analyzed by means of SEM/EDX analysis. After explantation, Mo levels in serum, urine, aortic vessel wall and organs were investigated via ICP-OES analysis. Furthermore, histological analyses of the liver, kidneys, spleen, brain and lungs were performed, as well as blood count and differentiation by FACS analysis. Levels of the C-reactive protein were measured in blood plasma of all the animals. In vitro and in vivo degradation behavior was very similar, with formation of uniform, non-passivating and dissolving product layers without occurrence of a localized corrosion attack. The in vitro degradation rate was 101.6 µg/(cm2·d) which corresponds to 33.6 µm/y after 28 days. The in vivo degradation rates of 12, 33 and 36 µg/(cm2·d) were observed after 3, 6 and 12 months for the samples properly implanted in the aortic vessel wall. This corresponds with a degradation rate of 13.5 µm/y for the 12-month cohort. However, the magnitude of degradation strongly depended on the implant site, with the wires incorporated into the vessel wall showing the most severe degradation. Degradation of the implanted Mo wire neither induced an increase in serum or urine Mo levels nor were elevated Mo levels found in the liver and kidneys compared with the respective controls. Only in the direct vicinity of the implant in the aortic vessel wall, a significant amount of Mo was found, which, however, was far below the amounts to be expected from degrading wires. No abnormalities were detected for all timepoints in histological and blood analyses compared to the control group. The C-reactive protein levels were similar between all the groups, indicating no inflammation processes. These findings suggest that dissolved Mo from a degrading implant is physiologically transported and excreted. Furthermore, radiographic and µCT analyses revealed excellent radiopacity of Mo in tissues. These findings and the unique combination with its extraordinary mechanical properties make Mo an interesting alternative for established BMMs.

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“…During the submission process, Sikora-Jasinska et al published a study describing in vivo degradation of Mo wires implanted in mouse aortae [36].…”

Section: Acknowledgmentsmentioning

confidence: 99%

Biocompatibility and Degradation Behavior of Molybdenum in an In Vivo Rat Model

et al. 2021

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“…Overall, our results are in agreement with recent published results of Redlich et al and Sikora-Jasinska et. al., which showed that the degradation behavior and biocompatibility of molybdenum is promising for future cardiovascular stents [ 5 , 29 ].…”

Section: Discussionmentioning

confidence: 99%

“…In the next steps, the in vivo biocompatibility and the exact degradation rates in complex organisms must be investigated. While Sikora-Jasinska et al showed the biocompatibility and degradation behavior in a flowing system [ 5 ] and Schauer et al demonstrated degradation in the abdominal aorta of rats [ 33 ], the behavior as an osteosynthesis system should be investigated separately. In particular, the degradation and dissolution behavior of molybdenum sheet metal should be investigated under in vivo conditions consistent with implant applications in craniomaxillofacial surgery.…”

Section: Discussionmentioning

confidence: 99%

“…Most polymer-based implants are made of polylactic acids [ 5 ], and they are designed to degrade in vivo via hydrolysis. The first of these systems for facial bone surgery have been available since the late 1980s [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…Molybdenum is a trace metal which is involved in and required for multiple enzymatic processes in the human body [ 20 , 21 ]. In recent publications, it is described as a bioresorbable material with high strength and exceptional mechanical properties [ 5 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

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Molybdenum as a Potential Biocompatible and Resorbable Material for Osteosynthesis in Craniomaxillofacial Surgery—An In Vitro Study

Toschka

Pöhle

Quadbeck

et al. 2022

IJMS

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Titanium and stainless steel are commonly known as osteosynthesis materials with high strength and good biocompatibility. However, they have the big disadvantage that a second operation for hardware removal is necessary. Although resorbable systems made of polymers or magnesium are increasingly used, they show some severe adverse foreign body reactions or unsatisfying degradation behavior. Therefore, we started to investigate molybdenum as a potential new biodegradable material for osteosynthesis in craniomaxillofacial surgery. To characterize molybdenum as a biocompatible material, we performed in vitro assays in accordance with ISO Norm 10993-5. In four different experimental setups, we showed that pure molybdenum and molybdenum rhenium alloys do not lead to cytotoxicity in human and mouse fibroblasts. We also examined the degradation behavior of molybdenum by carrying out long-term immersion tests (up to 6 months) with molybdenum sheet metal. We showed that molybdenum has sufficient mechanical stability over at least 6 months for implants on the one hand and is subject to very uniform degradation on the other. The results of our experiments are very promising for the development of new resorbable osteosynthesis materials for craniomaxillofacial surgery based on molybdenum.

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Additive Manufacturing of Biodegradable Molybdenum – From Powder to Vascular Stent

Bian,

Tong,

Gong

et al. 2024

Advanced Materials

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Magnesium, iron and zinc based biodegradable metals are widely recognized as promising candidate materials for the next generation of bioresorbable stent (BVS). However, none of those metal BVSs are perfect at this stage. Here, we developed a brand‐new BVS based on a novel biodegradable metal (Molybdenum, Mo) through additive manufacturing. Nearly full‐dense and crack‐free thin‐wall Mo was directly manufactured through selective laser melting (SLM) with fine Mo powder. Systemic analyses considering the forming quality, wall‐thickness, microstructure, mechanical properties and degradation behaviors were performed. Then, Mo‐based thin‐strut (≤ 100 µm) stents were successfully obtained through an optimized single‐track laser melting route. The SLMed thin‐wall Mo owns comparable strength to its Mg and Zn based counterparts (as‐drawn), whilst, it exhibits remarkable biocompatibility in vitro. Vessel related cells are well adhered and spread on SLMed Mo, and it exhibits a low risk of hemolysis and thrombus. The SLMed stent is compatible to vessel tissues in rat abdominal aorta, and it can provide sufficient support in an animal model as an extravascular stent. This work possibly opens a new era of manufacturing Mo‐based stents through additive manufacturing.This article is protected by copyright. All rights reserved

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In-vivo evaluation of molybdenum as bioabsorbable stent candidate

Cited by 15 publications

References 64 publications

Biocompatibility and Degradation Behavior of Molybdenum in an In Vivo Rat Model

Biocompatibility and Degradation Behavior of Molybdenum in an In Vivo Rat Model

Molybdenum as a Potential Biocompatible and Resorbable Material for Osteosynthesis in Craniomaxillofacial Surgery—An In Vitro Study

Additive Manufacturing of Biodegradable Molybdenum – From Powder to Vascular Stent

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