Wettability Properties of Standard Pyrolytic Carbon Bileaflet Mechanical Heart Valve Prostheses

Viganò, Giorgio; Brink, Gert H. ten; Pollack, Daniel; Mariani, Massimo A.; Kooi, Bart J.

doi:10.1080/24748706.2020.1716575

Cited by 2 publications

(3 citation statements)

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“…The values of the water contact angle for pyrolytic carbon, used primarily in medicine as a coating on the surface of bileaflet mechanical heart valve prostheses, are in the range of 86–110°. The exact value mainly depends on the synthesis temperature, types of precursor, and the presence of other elements, such as Si, used to improve mechanical parameters, mainly hardness and abrasion resistance [ 69 , 84 , 85 ]. In medicine, in particular for covering mechanical heart valves, low-temperature pyrolytic carbons are obtained at a temperature below 1500 °C [ 41 ].…”

Section: Resultsmentioning

confidence: 99%

Exploring CVD Method for Synthesizing Carbon–Carbon Composites as Materials to Contact with Nerve Tissue

Fraczek-Szczypta,

Kondracka,

Zambrzycki

et al. 2023

JFB

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The main purpose of these studies was to obtain carbon–carbon composites with a core built of carbon fibers and a matrix in the form of pyrolytic carbon (PyC), obtained by using the chemical vapor deposition (CVD) method with direct electrical heating of a bundle of carbon fibers as a potential electrode material for nerve tissue stimulation. The methods used for the synthesis of PyC proposed in this paper allow us, with the appropriate selection of parameters, to obtain reproducible composites in the form of rods with diameters of about 300 µm in 120 s (CF_PyC_120). To evaluate the materials, various methods such as scanning electron microscopy (SEM), scanning transmission electron microscope (STEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and tensiometer techniques were used to study their microstructural, structural, chemical composition, surface morphology, and surface wettability. Assessing their applicability for contact with nervous tissue cells, the evaluation of cytotoxicity and biocompatibility using the SH-SY5Y human neuroblastoma cell line was performed. Viability and cytotoxicity tests (WST-1 and LDH release) along with cell morphology examination demonstrated that the CF_PyC_120 composites showed high biocompatibility compared to the reference sample (Pt wire), and the best adhesion of cells to the surface among all tested materials.

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Section: Resultsmentioning

confidence: 99%

Exploring CVD Method for Synthesizing Carbon–Carbon Composites as Materials to Contact with Nerve Tissue

Fraczek-Szczypta,

Kondracka,

Zambrzycki

et al. 2023

JFB

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“…Nevertheless, microscopic analysis of the surfaces of mechanical heart valve revealed the presence of significant irregularities (Fig. 1) at a scale of 5 μm, which impact cell adhesion and thrombogenesis [7]. Besides, in order to explain the blood-artificial surface interactions, it seems reasonable to investigate the effective interaction between a blood droplet and the valve surface, as a liquid-solid wetting interaction.…”

Section: Introductionmentioning

confidence: 99%

“…This affinity/repulsion will further dictate the adsorption kinetics of the cells/proteins, which is found at the very beginning of the coagulation cascade, thus determining the BMVH thrombotic profile. Under ambient conditions (in air), BMHV occluders are intrinsically hydrophobic [7]. This peculiar feature is predominantly related to their chemical composition, thus to the material BMHV are made of (pyrolytic carbon), being On-X® valve the most hydrophobic.…”

Section: Introductionmentioning

confidence: 99%

New insights and novel perspectives in bileaflet mechanical heart valve prostheses thromboresistance

Vigano,

Shyam,

Mitra

et al. 2024

J Cardiothorac Surg

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Background Although well-known for their thromboresistance, bileaflet mechanical heart valves (BMHV) require lifelong anti-thrombotic therapy. This must be associated with a certain level of thrombogenicity. Since both thromboresistance and thrombogenicity are explained by the blood-artificial surface or liquid-solid interactions, the aim of the present study was to explore BMHV thromboresistance from new perspectives. The wettability of BMHV pyrolytic carbon (PyC) occluders was investigated in under-liquid conditions. The submerged BMHV wettability clarifies the mechanisms involved in the thromboresistance. Methods The PyC occluders of a SJM Regent™ BMHV were previously laser irradiated, to create a surface hierarchical nano-texture, featuring three nano-configurations. Additionally, four PyC occluders of standard BMHV (Carbomedics, SJM Regent™, Bicarbon™, On-X®), were investigated. All occluders were evaluated in under-liquid configuration, with silicon oil used as the working droplet, while water, simulating blood, was used as the surrounding liquid. The under-liquid droplet-substrate wetting interactions were analyzed using contact angle goniometry. Results All the standard occluders showed very low contact angle, reflecting a pronounced affinity for non-polar molecules. No receding of the contact line could be observed for the untreated occluders. The smallest static contact angle of around 61° could be observed for On-X® valve (the only valve made of full PyC). The laser-treated occluders strongly repelled oil in underwater conditions. A drastic change in their wetting behaviour was observed depending on the surrounding fluid, displaying a hydrophobic behaviour in the presence of air (as the surrounding medium), and showing instead a hydrophilic nature, when surrounded by water. Conclusions BMHV “fear” water and blood. The intrinsic affinity of BMHV for nonpolar fluids can be translated into a tendency to repel polar fluids, such as water and blood. The blood-artificial surface interaction in BMHV is minimized. The contact between blood and BMHV surface is drastically reduced by polar-nonpolar Van der Waals forces. The “hydro/bloodphobia” of BMHV is intrinsically related to their chemical composition and their surface energy, thus their material: PyC indeed. Pertaining to thromboresistance, the surface roughness does not play a significant role. Instead, the thromboresistance of BMHV lies in molecular interactions. BMHV wettability can be tuned by altering the surface interface, by means of nanotechnology.

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Wettability Properties of Standard Pyrolytic Carbon Bileaflet Mechanical Heart Valve Prostheses

Cited by 2 publications

References 0 publications

Exploring CVD Method for Synthesizing Carbon–Carbon Composites as Materials to Contact with Nerve Tissue

Exploring CVD Method for Synthesizing Carbon–Carbon Composites as Materials to Contact with Nerve Tissue

New insights and novel perspectives in bileaflet mechanical heart valve prostheses thromboresistance

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