| 1. |
- Ma, Hairui, et al.
(author)
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Effect of modulation period and thickness ratio on the growth and mechanical properties of heteroepitaxial c-Ti0.4Al0.6N/h-Cr2N multilayer films
- 2023
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In: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 472
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Journal article (peer-reviewed)abstract
- c-TiAlN/h-Cr2N multilayer thin films, with modulation period lambda of 10 nm, 20 nm, and 30 nm and different Cr2N/lambda thickness ratios (25 %, 50 % and 75 %), were deposited on c-plane sapphire using reactive DC magnetron sputtering. All multilayers exhibited preferred orientation [Cr2N(0001)/ TiAlN(111)](x), regardless of the modulation period and thickness ratios. X-ray diffraction f-scans revealed an influence of the Cr2N layer thickness on the overall orientation quality of the multilayer, where the thicker the Cr2N layer the higher orientation quality. Atomically resolved high-angle annular dark-field scanning transmission electron microscopy revealed well defined and homogeneous atom stacking in the Cr2N layers. In contrast, the cubic TiAlN layer was found to be composed of coherent cubic AlN-rich and TiN-rich regions. Additionally, the TiAlN layers were found with a higher density of grain boundaries compared to the Cr2N layers. Mechanical properties evaluation revealed that the film with a 20 nm period and 75 % Cr2N thickness ratio exhibited the highest hardness of 27.11 +/- 0.72 GPa and an reduced elastic modulus of 349.1 +/- 6.84 GPa. The hardness increased as the thickness of Cr2N increased, until reaching 10 nm, after which it remained at a high level (similar to 25 GPa).
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| 2. |
- Shin, Su Ryon, et al.
(author)
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Cell-laden Microengineered and Mechanically Tunable Hybrid Hydrogels of Gelatin and Graphene Oxide
- 2013
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In: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 25:44, s. 6385-6391
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Journal article (peer-reviewed)abstract
- Incorporating graphene oxide inside GelMA hydrogels enhances their mechanical properties and reduces UV-induced cell damage while preserving their favorable characteristics for 3D cell encapsulation. NIH-3T3 fibroblasts encapsulated in GO-GelMA microgels demonstrate excellent cellular viability, proliferation, spreading, and alignment. GO reinforcement combined with a multi-stacking approach offers a facile engineering strategy for the construction of complex artificial tissues.
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| 3. |
- Shin, Su Ryon, et al.
(author)
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Layer-by-Layer Assembly of 3D Tissue Constructs with Functionalized Graphene
- 2014
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In: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 24:39, s. 6136-6144
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Journal article (peer-reviewed)abstract
- Carbon-based nanomaterials have been considered promising candidates to mimic certain structure and function of native extracellular matrix materials for tissue engineering. Significant progress has been made in fabricating carbon nanoparticle-incorporated cell culture substrates, but only a limited number of studies have been reported on the development of 3D tissue constructs using these nanomaterials. Here, a novel approach to engineer 3D multilayer constructs using layer-by-layer (LbL) assembly of cells separated with self-assembled graphene oxide (GO)-based thin films is presented. The GO-based structures are shown to serve as cell adhesive sheets that effectively facilitate the formation of multilayer cell constructs with interlayer connectivity. By controlling the amount of GO deposited in forming the thin films, the thickness of the multilayer tissue constructs could be tuned with high cell viability. Specifically, this approach could be useful for creating dense and tightly connected cardiac tissues through the co-culture of cardiomyocytes and other cell types. In this work, the fabrication of stand-alone multilayer cardiac tissues with strong spontaneous beating behavior and programmable pumping properties is demonstrated. Therefore, this LbL-based cell construct fabrication approach, utilizing GO thin films formed directly on cell surfaces, has great potential in engineering 3D tissue structures with improved organization, electrophysiological function, and mechanical integrity.
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