Tag Archives: AFM Tips

Science & Technology

Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials

NANOSENSORS™ conductive diamond coated  CDT-NCLR AFM probes were used for the piezoresponse force microscopy ( PFM ) on non-piezoelectric dielectrics described in this brand new publication: “Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials” by Amir Abdollahi et al.

The autors show theoretically and experimentally, that large effective piezoelectric coefficients can be measured in non-piezoelectric dielectrics due to converse flexoelectricity.*

Figure 4 from “Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials” by Amir Abdollahi et al.: Study of converse flexoelectricity induced at the tip apex of an atomic force microscope cantilever as a function of the applied force. a Effective piezoelectric coefficient as a function of applied force for the SrTiO3 crystal. Filled squares correspond to the values obtained after the simulation. Empty circles correspond to the experimental values obtained with a NANOSENSORS CDT-FM AFM tip with a cantilever of medium stiffness (k ≈ 2.8 Nm−1) coated with doped diamond. The error bars correspond to the error of the linear fitting of the experimental data, which correlates the measured electromechanical amplitude of oscillation Δh with the Vac applied voltage. b The effective contact radius a scales with the force, and is determined by the tip radius. The experimental tip radius is obtained after the measurement of the nanoscale electromechanical response from the scanning electron microscopy image of the used tip. In this case, the tip radius of the diamond coated tip is 105 nm, and is observed to keep a spherical shape after the measurements
Figure 4 from “Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials” by Amir Abdollahi et al.:
Study of converse flexoelectricity induced at the tip apex of an atomic force microscope cantilever as a function of the applied force. a Effective piezoelectric coefficient as a function of applied force for the SrTiO3 crystal. Filled squares correspond to the values obtained after the simulation. Empty circles correspond to the experimental values obtained with a Nanosensors CDT-FMR tip with a cantilever of medium stiffness (k ≈ 2.8 Nm−1) coated with doped diamond. The error bars correspond to the error of the linear fitting of the experimental data, which correlates the measured electromechanical amplitude of oscillation Δh with the Vac applied voltage. b The effective contact radius a scales with the force, and is determined by the tip radius. The experimental tip radius is obtained after the measurement of the nanoscale electromechanical response from the scanning electron microscopy image of the used tip. In this case, the tip radius of the diamond coated tip is 105 nm, and is observed to keep a spherical shape after the measurements

*Amir Abdollahi, Neus Domingo, Irene Arias, Gustau Catalan
Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials
Nature Communicationsvolume 10, Article number: 1266 (2019)
DOI: https://doi.org/10.1038/s41467-019-09266-y

Please refer to this external link for the full article: https://www.nature.com/articles/s41467-019-09266-y

Open Access The article «Converse flexoelectricity yields large piezoresponse force microscopy signals in non-piezoelectric materials» by Amir Abdollahi et al. is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

 

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Get free NANOSENSORS qp-fast AFM probes at booth 613 at APS March 2019

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NANOSENSORS uniqprobe qp-fast AFM probe
NANOSENSORS uniqprobe qp-fast AFM probe
Science & Technology

Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering

Amyloidogenesis of α-synuclein (αS) is considered to be a pathological phenomenon related to Parkinson’s disease (PD).

In the publication “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering”  Ghibom Bhak, Soonkoo Lee, Tae-Hwan Kim, Ji-Hye Lee, Jee Eun Yang, Keehyoung Joo, Jooyoung Lee, Kookheon Char and Seung R. Paik have studied one particular type of meta-stable αS oligomers (Meta-αS-Os) since they act as a growing unit to exhibit the accelerated amyloid fibril formation in the presence of external stimuli such as shear force10, temperature change11, pH12, and organic solvents13 which are suspected to alter the structure of Meta-αS-Os into a self-associative state.*

Figure 2 from Ghibom Bhak et al., “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering” Unit-assembly of Meta-αS-Os. (a) 3-D AFM images of the scattered Meta-αS-Os species and an extended fibrillar structure on the mica surface. Black arrow represents the heat treatment at 80 °C for 30 min. (b) Thio-T binding fluorescence of αS after the centrifugal membrane filtration in the absence or presence of NaCl at various concentrations of 0, 0.015, 0.15, 1.5, 15, and 150 mM. (c) TEM images of the αS oligomers before (i) and after the membrane filtration at various concentrations of 0 (ii), 0.015 (iii), 0.15 (iv), 1.5 (v), 15 (vi) or 150 mM (vii). (d) AFM image showing coexistence of the oligomers and the amyloid fibrils at 1.5 mM NaCl following the membrane filtration. (e) AFM height profile of the oligomeric and fibrillar species. The oligomeric and fibrillar species of αS on the mica were analyzed with AFM in a tapping mode with a Super Sharp AFM probe (SSS-NCHR, NANOSENSORS, Switzerland).
Figure 2 from Ghibom Bhak et al., “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering”:
Unit-assembly of Meta-αS-Os. (a) 3-D AFM images of the scattered Meta-αS-Os species and an extended fibrillar structure on the mica surface. Black arrow represents the heat treatment at 80 °C for 30 min. (b) Thio-T binding fluorescence of αS after the centrifugal membrane filtration in the absence or presence of NaCl at various concentrations of 0, 0.015, 0.15, 1.5, 15, and 150 mM. (c) TEM images of the αS oligomers before (i) and after the membrane filtration at various concentrations of 0 (ii), 0.015 (iii), 0.15 (iv), 1.5 (v), 15 (vi) or 150 mM (vii). (d) AFM image showing coexistence of the oligomers and the amyloid fibrils at 1.5 mM NaCl following the membrane filtration. (e) AFM height profile of the oligomeric and fibrillar species.

“For the assessment of heat-induced oligomeric unit assembly, an aliquot (10 μl) containing αS oligomers was placed on a cleaved mica surface. Following 30-min incubation at room temperature, the mica was immersed in fresh 20 mM Mes (pH 6.5) and incubated at 80 °C for another 30 min. After the heat-treated mica was cleaned with excessive distillated water, the oligomeric and fibrillar species of αS on the mica were analyzed with AFM in a tapping mode with a Super Sharp AFM tip (SSS-NCHR, NANOSENSORS, Switzerland). To reveal coexistence of the oligomers and fibrils, the αS species (10 μl) was adsorbed on the mica coated with poly-l-lysine for 5 min at room temperature. After the mica was washed with distilled water 5 times and dried in vacuum chamber, AFM analysis was done in a tapping mode.”*

“Meta-αS-Os have played a growing unit for the unit-assembly-based facilitated amyloid fibril formation. Their unit-assembly was examined on the surface of mica immersed in 20 mM Mes (pH 6.5) at 80 °C for 30 min. In the 3-D AFM images, the scattered Meta-αS-Os on the mica surface became aligned with each other to form the extended fibrils following the heat treatment (Fig. 2a). This phenomenon reflects general two-step process of protein-surface interaction showing initial reversible binding of the oligomers to the surface followed by their irreversible stabilization into the amyloid fibrils via the transition of Meta-αS-Os into type-Bon oligomers upon the heat treatment. […] AFM analysis revealed that the particulates and the short fibrils of αS obtained with 1.5 mM NaCl had almost identical height profile with the maximum height of 4 nm (Fig. 2d,e).”*

[…]

“AFM analysis revealed that the particulates and the short fibrils of αS obtained with 1.5 mM NaCl had almost identical height profile with the maximum height of 4 nm (Fig. 2d,e).”*

*Ghibom Bhak, Soonkoo Lee, Tae-Hwan Kim, Ji-Hye Lee, Jee Eun Yang, Keehyoung Joo, Jooyoung Lee, Kookheon Char and Seung R. Paik
Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering
Nature Scientific Reports, volume 8, Article number: 14295 (2018)
DOI: https://doi.org/10.1038/s41598-018-32655-0

Open Access: The article “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering” by  Ghibom Bhak et al. is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.