Comparative SEM and TEM analyses of apatite phases prepared by a multi-sample loading device

Kim, Jung-Kyun; Kwon, Yong-Eun; Lee, Sang-Gil; Jeong, Jong-Man; Kim, Jin-Gyu; Kim, Youn-Joong

doi:10.1016/j.matchar.2017.11.009

Cited by 5 publications

(14 citation statements)

References 23 publications

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“…Both synthetic and natural apatite samples (Kim et al, 2018;Song et al, 2012;Meneghini et al, 2003;Young et al, 1969;Kim et al, 2017) were used to test the efficacy of the modified holder for STEM-in-SEM EDS analysis. While commercial SAp was available in powder form, mineral apatite (MAp, 470104-508, Ward's Science) and fossil apatite (FAp, left femur from a Cretaceous dinosaur (Kim et al, 2017)) required powdering via diamond sawing (debris collection), ultrasonic drilling, and/or were ground with an agate mortar and pestle in order to avoid chemical and structural alterations.…”

Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

“…While commercial SAp was available in powder form, mineral apatite (MAp, 470104-508, Ward's Science) and fossil apatite (FAp, left femur from a Cretaceous dinosaur (Kim et al, 2017)) required powdering via diamond sawing (debris collection), ultrasonic drilling, and/or were ground with an agate mortar and pestle in order to avoid chemical and structural alterations. In case of bone apatite (BAp), aiming to retain its original state, we avoided using chemical agents that were involved in decalcification and fixation (Kim et al, 2018). The bone sections were cut using a diamond wire saw (Model 3242, Well), were subsequently dried in a critical point dryer (Samdri®-PVT-3D, Tousimis) for an hour, and were finally powdered using a freezer mill (SPEX Sample Prep™).…”

Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

“…The bone sections were cut using a diamond wire saw (Model 3242, Well), were subsequently dried in a critical point dryer (Samdri®-PVT-3D, Tousimis) for an hour, and were finally powdered using a freezer mill (SPEX Sample Prep™). The collected BAp was added to a 70% ethanol solution (Kim et al, 2018). All the other apatite samples were added into 99.9% ethanol solutions, and the solutions were stored in room temperature.…”

Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

“…The nanoparticles within each sample solution were separated into individual particles by a probe sonicator (EpiShear, Active Motif). We sprayed each sample solution onto each TEM grid using the custom-made ultrasonic sprayer to prevent aggregation between particles as well as to disperse the sample particles widely enough during the drying of the solution on the grid (Kim et al, 2018). For comparison, we tested the same samples with a Zeiss grid holder (12x STEM-probenhalter) for the FE-SEM, which is manufactured by Carl Zeiss, but covered with a custom-made Be plate to avoid generation of Al signals.…”

Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

“…Each EDS spectrum was obtained at a single session in consistent analytical conditions, and intensity ratios of Ca/P and O/P were interpreted. Through comparative analysis of apatite phases with both pure and mixed chemistry, we were able to distinguish specific chemical characteristics of the four apatite phases which have similar chemistry (Lee et al, 2013;Kim et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Development of SEM and STEM-in-SEM grid holders for EDS analysis and their applications to apatite phases

Kwon

Kim

Kim³

et al. 2019

J Anal Sci Technol

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Background: With the application of the scanning transmission electron microscopy (STEM) detector, transmitted electron images similar to transmission electron microscopy (TEM) can be obtained from scanning electron microscopy (SEM), which is referred to STEM-in-SEM imaging. Compared to TEM-energy dispersive spectroscopy (EDS), SEM-EDS is expected to be more efficient and reliable for chemical analysis of TEM specimens due to the larger sample space in SEM and the higher takeoff angle of the SEM-EDS detector. Unfortunately, this advantage is not well applied to TEM specimens in practice, mainly because of fault signals generated from the commercial grid holders used in SEM and STEM-in-SEM. This study is designed to solve this problem by modifying the commercial holders and to test them through EDS analysis of apatite phases. Findings: We first changed the way of assembling parts of the commercial multi-grid holder for SEM. This new assembly was capable of producing a thinner upper cover part, resulting in the reduction of the EDS fault signals generated from the holder. Furthermore, the thin upper part allowed us to get images in shorter working distances, that is, at higher magnifications. This design concept was also applied to the commercial single-grid holder for STEM-in-SEM, producing a new multi-grid holder to be used for loading multiple samples. Conclusion: We confirmed that the new holders produced reliable chemical data from apatite phases. In case of oxygen analysis, despite of low electron brightness from the tungsten source, 5 kV provided more stable acquisition and signal yields than 15 kV. We expect that these modified holders facilitate more efficient EDS analysis for multiple samples under the same analytical conditions in SEM and STEM-in-SEM.

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Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

Section: Application Of the Modified Holders To Multiple Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development of SEM and STEM-in-SEM grid holders for EDS analysis and their applications to apatite phases

Kwon

Kim

Kim³

et al. 2019

J Anal Sci Technol

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Self‐Assembled Type I Collagen‐Apatite Fibers with Varying Mineralization Extent and Luminescent Terbium Promote Osteogenic Differentiation of Mesenchymal Stem Cells

Romero‐Castillo

López‐Ruiz

Marchal

et al. 2020

Macromolecular Bioscience

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This work explores in depth the simultaneous self‐assembly and mineralization of type I collagen by a base‐acid neutralization technique to prepare biomimetic collagen‐apatite fibrils with varying mineralization extent and doped with luminescent bactericidal Tb3+ ions. Two variants of the method are tested: base‐acid titration, a solution of Ca(OH)2 is added dropwise to a stirred solution containing type I collagen dispersed in H3PO4; and direct mixing, the Ca(OH)2 solution is added by fast dripping onto the acidic solution. Only the direct mixing variant yielded an effective control of calcium phosphate polymorphism. Luminescence spectroscopy reveals the long luminescence lifetime and high relative luminescence intensity of the Tb3+‐doped materials, while two‐photon confocal fluorescence microscopy shows the characteristic green fluorescence light when using excitation wavelength of 458 nm, which is not harmful to bone tissue. Cytotoxicity/viability tests reveal that direct mixing samples show higher cell proliferation than titration samples. Additionally, osteogenic differentiation essays show that all mineralized fibrils promote the osteogenic differentiation, but the effect is more pronounced when using samples prepared by direct mixing, and more notably when using the Tb3+‐doped mineralized fibrils. Based on these findings it is concluded that the new nanocomposite is an ideal candidate for bone regenerative therapy.

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Herbal nano-formulations for topical delivery

Khogta

Patel

Barve

et al. 2020

Journal of Herbal Medicine

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Comparative SEM and TEM analyses of apatite phases prepared by a multi-sample loading device

Cited by 5 publications

References 23 publications

Development of SEM and STEM-in-SEM grid holders for EDS analysis and their applications to apatite phases

Development of SEM and STEM-in-SEM grid holders for EDS analysis and their applications to apatite phases

Self‐Assembled Type I Collagen‐Apatite Fibers with Varying Mineralization Extent and Luminescent Terbium Promote Osteogenic Differentiation of Mesenchymal Stem Cells

Herbal nano-formulations for topical delivery

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