Browsing by Author "Zambrano, Dario F."

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    Bio-tribological characterization of additives in synovial fluid - usage of graphene, Ti3C2Tx and their synergistic effects
    (2025) Ramteke R., Sangharatna Munneshwar; Ugarte Muñoz, Alfonso E.; Zambrano, Dario F.; Ramos Grez, Jorge; Rosenkranz, Andreas; Marian, Max
    Synovial joints play a crucial role in limb biomechanics, depending on advanced lubrication systems to reduce wear. However, disruptions caused by injury or disease often led to the need for joint replacements. Although additive manufacturing enables the production of customized implants, achieving optimal wear resistance is still a significant challenge. This research explores the use of nano-additives in synovial fluid (SF). In this context, we examine the dispersion stability, surface wettability, dynamic viscosity, and bio-tribological behavior of SF enhanced by graphene (G), MXene (Ti3C2Tx), and their hybrid (G-Ti3C2Tx) in the concentrations of 0.5, 2, and 10 mg/mL, respectively. Results show that G and the hybrid maintained stable dispersions in SF, while Ti3C2Tx shows slight sedimentation at lower concentrations. Both G and Ti3C2Tx substantially improved wettability, with the most pronounced effect observed at 10 mg/mL for Ti3C2Tx (29.8 % reduction in contact angle). The bio-tribological analysis indicates that the hybrids induced a superior wear resistance (78.3 % wear reduction at 2 mg/mL). These findings highlight the potential of hybrid, in enhancing the bio-tribological properties of SFs, which is highly prospective to enhance knee prostheses and arthritis management.
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    Biotribological Performance of Multilayer Ti- and Mo-Based MXene Coatings
    (2025) Ramteke R., Sangharatna Munneshwar; Molina, Ricardo; Zambrano, Dario F.; Marian, Max; Rosenkranz, Andreas
    Metallic materials are extensively utilized in biomedical implants due to their excellent strength and corrosion resistance. However, friction and wear-related issues remain important challenges in load-bearing implant applications. To address these concerns, multilayer Ti3C2T x , Mo2TiC2T x , and Mo2Ti2C3T x coatings were deposited onto stainless steel substrates in two distinct thickness ranges (lower: similar to 100 to 150 nm; higher: similar to 225 to 275 nm) and biotribologically tested under simulated body fluid lubrication conditions. Our results revealed that low coating thicknesses of Mo2TiC2T x demonstrated the most favorable biotribological performance, reducing the wear rate by up to 33% and consistently lowering the coefficient of friction, with reductions of up to 56% compared to uncoated references, owing to their ability to form durable tribo-films under SBF lubrication. In contrast, Ti3C2T x coatings increased friction and wear under considered conditions, while Mo2Ti2C3T x showed a moderate COF reduction but higher wear rates, particularly at higher coating thicknesses and loads. These findings emphasize the superior self-lubricating properties of Mo2TiC2T x coatings, thus highlighting their potential to enhance the durability and longevity of load-bearing biomedical implants.
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    Combining multi-scale surface texturing and DLC coatings for improved tribological performance of 3D printed polymers
    (2023) Marian, Max; Zambrano, Dario F.; Rothammer, Benedict; Waltenberger, Valentin; Boidi, Guido; Krapf, Anna; Merle, Benoit; Stampfl, Jürgen; Rosenkranz, Andreas; Gachot, Carsten; Grützmacher, Philipp G.
    Polymer components fabricated by additive manufacturing typically show only moderate strength and low temperature stability, possibly leading to severe wear and short lifetimes especially under dry tribological sliding. To tackle these shortcomings, we investigated the combination of single- and multi-scale textures directly fabricated by digital light processing with amorphous diamond-like carbon (DLC) coatings. The topography of the samples and conformity of the coatings on the textures are assessed and their tribological behaviour under dry conditions is studied. We demonstrate that the surface textures have a detrimental tribological effect on the uncoated samples. This changes with the application of DLC coatings since friction substantially reduces and wear of the textures is not observed anymore. These trends are attributed to the protection of the underlying polymer substrate by the coatings and a reduced contact area. The best tribological performance is found for a coating with highest hardness and hardness-to-elasticity ratios. Moreover, multi-scale textures perform slightly better than single-scale textures due to a smaller real contact area. Summarizing, we verified that the high flexibility and low production costs of 3D printing combined with the excellent mechanical and tribological properties of DLC results in synergistic effects with an excellent performance under dry sliding conditions
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    Mechanical and Bio-tribological Behavior of Ti3C2Tx-Reinforced CoCrMo Composites Fabricated by Additive Manufacturing
    (2025) Ramteke, Sangharatna M.; Ramos Grez, Jorge; Zambrano, Dario F.; Rosenkranz, Andreas; Marian, Max
    This study presents the bio-tribological analysis of Ti3C2Tx-reinforced CoCrMo matrix composites fabricated by laser beam powder bed fusion. Raman spectroscopy confirmed the structural and functional integrity during metal matrix composite (MMC) fabrication, while Vickers hardness increased with Ti3C2Tx content. Together with roughness and wettability, Ti3C2Tx-reinforced CoCrMo composites create a favorable balance between hardness, surface roughness, and hydrophilicity, making them suitable for biomedical applications. Bio-tribological analyses under dry and substitute synovial body fluid (SBF)-lubricated conditions revealed a substantial wear reduction of 78 and 39% compared to reference. These findings underscore Ti3C2Tx' ability to mitigate wear through enhanced interfacial interactions and lubrication, promising advancements in biomedical implants.
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    Ti3C2Tx and Mo2TiC2Tx MXenes as additives in synovial fluids - towards an enhanced biotribological performance of 3D-printed implants
    (2024) Marian, Max; Esteban, Cotty D. Quiroz; Zambrano, Dario F.; Ramteke, Sangharatna M.; Grez, Jorge Ramos; Wyatt, Brian C.; Patenaude, Jacob; Wright, Bethany G.; Anasori, Babak; Rosenkranz, Andreas
    Synovial joints, critical for limb biomechanics, rely on sophisticated lubrication systems to minimize wear. Disruptions, whether from injury or disease, often necessitate joint replacements. While additive manufacturing offers personalized implants, ensuring wear resistance remains a challenge. This study delves into the potential of Ti3C2Tx 3 C 2 T x and Mo2TiC2Tx 2 TiC 2 T x nanosheets in mitigating wear of additively manufactured cobalt-chromium tungsten alloy substrates when incorporated as additives into synovial fluid. The colloidal solutions demonstrate an excellent stability, a crucial factor for reproducible assays and potential clinical applicability. Analysis of contact angles and surface tensions reveals MXene-induced alterations in substrate wettability, while maintaining their general hydrophilic character. Viscosity analysis indicates that MXene addition reduces the dynamic viscosity, particularly at higher concentrations above 5 mg/mL, thus enhancing dispersion and lubrication properties. Friction and wear tests demonstrate a dependency on the MXene concentration, while Ti3C2Tx 3 C 2 T x exhibits stable friction coefficients and up to 77 % wear reduction at 5 mg/mL, which was attributed to the formation of a wear- protecting tribo-film (amorphous carbon and MXene nano-sheets). Our findings suggest that Ti3C2Tx, 3 C 2 T x , when supplied in favorable concentrations, holds promise for reducing wear in biotribological applications, offering avenues for future research into optimizing MXene utilization in load-bearing joint replacements and other biomedical devices.