Tag Archives: Platinum Silicide AFM probes

Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy

The dielectric permittivity of membranes is important for many fundamental electrophysiological functions like selective transport in ion channels, action potential propagation and energy generation.*

In their article “Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy” George Gramse, Andreas Schönhals and Ferry Kienberger investigate the nearfield dipole mobility of protein membranes in a wide frequency range from 3 kHz to 10 GHz.*

They achieved their results by adding the frequency as a second fundamental dimension to quantitative dielectric microscopy thereby demonstrating the possibilities of broadband dielectric microscopy for the investigation of dynamic processes in cell bioelectricity at the individual molecular level. Furthermore, the technique may also shed light on local dynamic processes in related materials science applications like semiconductor research or nano-electronics.*

All AFM measurements were carried out at 25 °C using a NANOSENSORS Platinum Silicide AFM probe ( PtSi-FM ).

Fig. 2 from “Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy” by Gramse et al.: image a) shows the AFM topography and image b) shows the corresponding C′′(z)/C′′dry(z) image obtained in lift mode at z = 10 nm above the last scan line and at a frequency of ω = 10 kHz (inset at 1 MHz). The corresponding topography and C′′(z)/C′′dry(z) profile lines are shown in  image c). Solid lines correspond to profile lines at 10 kHz and the dashed line to 1 MHz. Image d) shows the normalized dielectric spectra on the substrate and protein membrane at constant height z′ = 15 nm and lift mode z = 15 nm. Black solid lines represent fitting with eqn (1) and (2). image e) shows the resulting complex dielectric functions ε′r(f) and ε′′r(f)2 (using the relation ε′′r(f) = −(π/2∂)ε′r/∂ln(2πf)38). All measurements are carried out at 25 °C using conductive and wear-resistant Platinum Silicide AFM probes  (PtSi-FM ) from NANOSENSORS (Germany). Humidity was changed and left to stabilize for 2–3 hours. Imaging conditions were adjusted to maintain the lift distance for the dielectric images identical.

Fig. 2 from “Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy” by Gramse et al.: (a) AFM topography and (b) corresponding C′′(z)/C′′dry(z) image obtained in lift mode at z = 10 nm above the last scan line and at a frequency of ω = 10 kHz (inset at 1 MHz). The corresponding topography and C′′(z)/C′′dry(z) profile lines are shown in (c). Solid lines correspond to profile lines at 10 kHz and the dashed line to 1 MHz. (d) Normalized dielectric spectra on the substrate and protein membrane at constant height z′ = 15 nm and lift mode z = 15 nm. Black solid lines represent fitting with eqn (1) and (2). (e). Resulting complex dielectric functions ε′r(f) and ε′′r(f)2 (using the relation ε′′r(f) = −(π/2∂)ε′r/∂ln(2πf)38).
All measurements are carried out at 25 °C using PtSi-FM tips from NANOSENSORS (Germany). Humidity was changed and left to stabilize for 2–3 hours. Imaging conditions were adjusted to maintain the lift distance for the dielectric images identical.

*Georg Gramse, Andreas Schönhals, Ferry Kienberger
Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy
Nanoscale, 2019, 11, 4303-4309
DOI: 10.1039/C8NR05880F

Please follow this external link for the full article: https://pubs.rsc.org/en/content/articlehtml/2019/nr/c8nr05880f

Open Access The article “Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy” by George Gramse, Andreas Schönhals and Ferry Kienberger is licensed under a Creative Commons Attribution 3.0 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. To view a copy of this license, visit https://creativecommons.org/licenses/by/3.0/

Conductive Polymer-Ag Honeycomb Thin Film: The Factors Affecting the Complexity of the Microstructure

“Fast growth in Internet of Things (IoT) has attracted a lot of attention of flexible and easily processable hybrid organic-inorganic nanomaterials, integrated into modern electronics and applied in multidisciplinary fields. Nanoporous and microporous thin films with regularly ordered pores exemplified by honeycomb films have received considerable interest due to its diverse potential applications, such as optoelectronics, microstructured electrodes, sensors, and charge storage devices, synthetic templates for nanoparticles, catalytic supports with large surface areas, scaffold materials in biotechnology and separation. Various materials have been applied for the synthesis of the honeycomb structures, such as star polymers, hyperbranched polymers, surfactant-encapsulated polyoxometalate for polystyrene, cross-linkable monomers,and biological molecules.”*

In the article cited here Sajjad Husain Mir and Bungo Ochiai have investigated the factors affecting the micro-structuration of the polymer-Ag honeycomb films and investigated the I-V characteristics. The pore sizes of the polymer-Ag honeycomb films were feasibly tuned by altering various parameters, namely, casting volume, polymer concentration, and molecular weight of the grafted poly(methyl methacrylate) (PMMA) chain.*

The current-sensing scanning probe microscopy (CSSPM) images for this article were taken using a NANOSENSORS™ Platinum-Silicide AFM probe. ( PtSi-CONT ).

Figure 6 from Mir & Ochiai "Conductive Polymer-Ag Honeycomb Thin Film: The Factors Affecting the Complexity of the Microstructure* a) Topography SPM image, and b)I-V curves of the polymer-Ag honeycomb film on HOPG (preparation conditions for polymer-Ag honeycomb film: poly(NVK-co-MAH)-g-PMMA from PMMA (Mn=2100), 0.3 mg mL−1 and 50μL; measurement conditions: topography SPM image was taken by contact mode using microfabricated PtSi- coated cantilever (f0: 15 kHz, C: 0.2 N m−1), and the I-V curves were taken at specific points. NANOSENSORS PtSi-CONT AFM probes were used for the Current-sensing scanning probe microscopy (CSSPM) images
Figure 6 from Mir & Ochiai “Conductive Polymer-Ag Honeycomb Thin Film: The Factors
Affecting the Complexity of the Microstructure*
a) Topography SPM image, and b) I-V curves of the polymer-Ag honeycomb film on HOPG (preparation conditions for polymer-Ag honeycomb film: poly(NVK-co-MAH)-g-PMMA from PMMA (Mn=2100), 0.3 mg mL−1 and 50μL; measurement conditions: topography SPM image was taken by contact mode using microfabricated PtSi-coated cantilever (f0: 15 kHz, C: 0.2 N m−1), and the I-V curves were taken at specific points.

*Sajjad Husain Mir,  Bungo Ochiai
Conductive Polymer-Ag Honeycomb Thin Film: The Factors Affecting the Complexity of the Microstructure
Journal of The Electrochemical Society, 165 (8) B3030-B3034 (2018)
JES Focus issue on ubiquitous sensors and systems for IOT
DOI: 10.1149/2.0031808jes

Open Access The article “Conductive Polymer-Ag Honeycomb Thin Film: The Factors Affecting the Complexity of the Microstructure” by Sajjad Husain Mir and Bungo Ochiai 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 https://creativecommons.org/licenses/by/4.0/.