| 1. |
- Fu, L., et al.
(författare)
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Three-Dimensional Insights into Interfacial Segregation at the Atomic Scale in a Nanocrystalline Glass-Ceramic
- 2021
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 21:16, s. 6898-6906
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of dopant atoms plays a key role in the effectiveness of doping, thereby requiring delicate characterizations. In this study, we found that energy-dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS) techniques in scanning transmission electron microscopy (STEM) were not adequate to reveal the distribution of yttrium and the chemical composition of the ZrO2/SiO2 heterophase interface in an yttrium-doped ZrO2-SiO2 nanocrystalline glass-ceramic. Atom probe tomography (APT) is rarely utilized to characterize ceramics due to some inherent difficulties. However, we successfully revealed the three-dimensional distribution of ZrO2 nanocrystallites and SiO2 matrix at the atomic scale with APT under optimized and well-controlled conditions. We also found that the ZrO2 nanocrystallites had a special core-shell structure, with a thin Zr/Si interfacial layer as a shell and a ZrO2 solid solution as a core. Yttrium dopants showed interfacial segregation at both ZrO2 grain boundaries and the ZrO2/SiO2 heterophase interfaces.
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| 2. |
- Grandfield, K., et al.
(författare)
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Atom probe tomography for biomaterials and biomineralization
- 2022
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061. ; 148, s. 44-60
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Tidskriftsartikel (refereegranskat)abstract
- Biominerals and biomaterials are part of our daily lives, from our skeleton and teeth to coral reefs and carbon-capturing single-cell organisms in the oceans, to engineered ceramics comprising our toothpaste and bone replacements. Many biominerals are hierarchically structured with remarkable material prop-erties that arise from their unique combination of organic and inorganic components. Such structural hierarchy is often formed through a process of biomineralization. However, many fundamental questions remain regarding mineralization events in bones or teeth, and near biomaterials, partly due to the chal-lenges in characterizing three-dimensional (3D) structure and chemical composition simultaneously at the nanometer scale. Atom probe tomography (APT) is a 3D characterization technique that combines both sub-nanometer spatial resolution and compositional sensitivity down to tens of parts per million. While APT is well-established in application to conventional engineering materials, recent years have seen its expansion into biomineralization research. Here, we focus our review on APT applications to biominerals, biomaterials and biointerfaces, providing a high-level summary of findings, as well as a primer on theory and best practices specific to the biomineralization community. We show that APT is a promising char-acterization tool, where its unique ability to quantify 3D chemical composition is not only complemen-tary to other microscopy techniques but could become an integral part of biomaterial research. With the emerging trends of correlative and cryogenic workflow, notwithstanding the challenges outlined herein, APT has the potential to improve understanding of a broader range of biomaterials, while deriving inno-vative perspectives on clinical applications and strategies for biomaterial design.Statement of significance Atom probe tomography (APT) is a three-dimensional characterization technique that can provide quanti-tative elemental and isotopic analysis with sub-nanometer resolution and compositional sensitivity down to tens of parts per million. These capabilities make it uniquely positioned for the analysis of biominer-alized materials, both natural and synthetic. Here, we review the various applications of APT to the field of biomineralization, including applications in biominerals, biomaterials, biointerfaces and other biolog-ical materials, such as cells or proteins. A brief but comprehensive summary of the relevant technical concepts, limitations, and future perspectives to enable growth in this field are also included. Although APT is relatively new to the field of biomineralization, it has shown the potential to transform our basic understanding of biomineralization mechanisms and better inform biomaterials design.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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| 3. |
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| 4. |
- Micheletti, Chiara, et al.
(författare)
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Bone mineral organization at the mesoscale: A review of mineral ellipsoids in bone and at bone interfaces
- 2022
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061. ; 142, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Much debate still revolves around bone architecture, especially at the nano- and microscale. Bone is a remarkable material where high strength and toughness coexist thanks to an optimized composition of mineral and protein and their hierarchical organization across several distinct length scales. At the nanoscale, mineralized collagen fibrils act as building block units. Despite their key role in biological and mechanical functions, the mechanisms of collagen mineralization and the precise arrangement of the organic and inorganic constituents in the fibrils remains not fully elucidated. Advances in three-dimensional (3D) characterization of mineralized bone tissue by focused ion beam-scanning electron microscopy (FIB-SEM) revealed mineral-rich regions geometrically approximated as prolate ellipsoids, much larger than single collagen fibrils. These structures have yet to become prominently recognized, studied, or adopted into biomechanical models of bone. However, they closely resemble the circular to elliptical features previously identified by scanning transmission electron microscopy (STEM) in two-dimensions (2D). Herein, we review the presence of mineral ellipsoids in bone as observed with electron-based imaging techniques in both 2D and 3D with particular focus on different species, anatomical locations, and in proximity to natural and synthetic biomaterial interfaces. This review reveals that mineral ellipsoids are a ubiquitous structure in all the bones and bone-implant interfaces analyzed. This largely overlooked hierarchical level is expected to bring different perspectives to our understanding of bone mineralization and mechanical properties, in turn shedding light on structure-function relationships in bone. Statement of significance: In bone, the hierarchical organization of organic (mainly collagen type I) and inorganic (calcium-phosphate mineral) components across several length scales contributes to a unique combination of strength and toughness. However, aspects related to the collagen-mineral organization and to mineralization mechanisms remain unclear. Here, we review the presence of mineral prolate ellipsoids across a variety of species, anatomical locations, and interfaces, both natural and with synthetic biomaterials. These mineral ellipsoids represent a largely unstudied feature in the organization of bone at the mesoscale, i.e., at a level connecting nano- and microscale. Thorough understanding of their origin, development, and structure can provide valuable insights into bone architecture and mineralization, assisting the treatment of bone diseases and the design of bio-inspired materials. © 2022 Acta Materialia Inc.
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| 5. |
- Micheletti, Chiara, et al.
(författare)
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Multimodal and Multiscale Characterization of the Bone-Bacteria Interface in a Case of Medication-Related Osteonecrosis of the Jaw
- 2022
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Ingår i: JBMR Plus. - : Wiley. - 2473-4039. ; 6:12
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Tidskriftsartikel (refereegranskat)abstract
- Medication-related osteonecrosis of the jaw (MRONJ) is a known side effect of bisphosphonates (BPs). Although bacterial infection is usually present, the etiology of MRONJ remains unknown. Here we apply a multimodal and multiscale (micro-to-nano) characterization approach to investigate the interface between necrotic bone and bacteria in MRONJ. A non-necrotic bone sample was used as control. Both necrotic and non-necrotic bone samples were collected from the jaw of a female individual affected by MRONJ after using BPs for 23 years. For the first time, resin cast etching was used to expose bacteria at the necrotic site. The bone-bacteria interface was also resolved at the nanoscale by scanning transmission electron microscopy (STEM). Nanosized particulates, likely corresponding to degraded bone mineral, were often noted in close proximity to or enclosed by the bacteria. STEM also revealed that the bone-bacteria interface is composed of a hypermineralized front fading into a highly disordered region, with decreasing content of calcium and phosphorus, as assessed by electron energy loss spectroscopy (EELS). This, combined with the variation in calcium, phosphorus, and carbon across the necrotic bone-bacteria interface evaluated by scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) and the lower mineral-to-matrix ratio measured by micro-Raman spectroscopy in necrotic bone, indicates the absence of a mineralization front in MRONJ. It appears that the bone-bacteria interface originates not only from uncontrolled mineralization but also from the direct action of bacteria degrading the bone matrix. (c) 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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| 6. |
- Palmquist, Anders, 1977, et al.
(författare)
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Bone-implant interface on the nano-scale.
- 2012
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Ingår i: Abstract, 4th International Symposium Interface biology of implants, Rostock-Warnemunde, Germany.. ; May, 9-11
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
- Shah, Furqan A., et al.
(författare)
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Laser surface modification and the tissue-implant interface
- 2016
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Ingår i: Laser Surface Modification of Biomaterials: Techniques and Applications. - Leyden : Elsevier, Inc.. ; , s. 253-280
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Bokkapitel (refereegranskat)abstract
- The osseointegration process around metal implants may be controlled by biomimetic design of implantable surfaces to mimic the multiscale nature of bone. The use of lasers for implant surface modification has great potential for creating hierarchical structures - from macrogeometries to site-specific nanoscale modifications. On the macroscale, features of 100-200. m are believed to be optimal for the formation of remodelled osteonal, while microscale texturing may be utilised to modulate cellular attachment and soft tissue guidance around metallic implants. Collagen, bone apatite and other biomolecules are all nanoscale structures and closely govern the mechanical properties of bone. Hierarchical structuring of implant surfaces therefore makes it possible to guide cellular recruitment and adhesion, and control the adsorption of signalling molecules, to enhance bone growth and biomechanical retention. © 2016 Elsevier Ltd All rights reserved.
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| 9. |
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