Tag Archives: force measurements

Calibration Service for AFM Cantilevers

The NANOSENSORS screencast on the calibration service for AFM cantilevers has just reached the 1500 views mark.

Accurately determined AFM cantilever properties are very important for quantitative force measurements. Force constant and resonance frequency are determined either by thermal tune, the Sader- or the dimensional method, respectively. Usually, the thermal tune method delivers the most precise values, but suffers from the fact that the AFM tip has to get in contact with the surface to calibrate the photo-detector sensitivity. This procedure may damage or break the AFM tip!

The Characterization of AFM Cantilevers is a service from the NANOSENSORS Special Developments List which can be ordered as add-on to AFM probes of the standard PointProbe®Plus, SuperSharp Silicon and tipless cantilevers product range or special developments (force constant < 1N/m and resonance frequency < 2 MHz) and provides measured Spring Constants, Resonance Frequencies and Quality Factors.

NANOSENSORS™ offers a thermal tune calibration procedure performed by Laser vibrometry. This method is contact free and therefore does no damage the AFM tip, but preserves the original AFM tip quality. To ensure the highest level of accuracy NANOSENSORS™AFM  cantilever calibration method is calibrated with a standard, certified by the national German metrology institute.

This service is part of our Special Development List (SDL).
Please have a look at http://www.nanosensors.com/pdf/SpecialDevelopmentsList.pdf or contact us at info(at)nanosensors.com for further information.

Supercritical carbon dioxide decellularization of plant material to generate 3D biocompatible scaffolds

Biocompatible scaffolds that can be repopulated with human cells have many uses such serving as replacement organs and tissues. Therefore there is an increasing interest in plant-based biomaterials for tissue engineering.*

As the above mentioned scaffolds should mimic the in vivo tissue environment closely they need to provide a fitting structural and biomechanical support to the cells while at the same time promoting cell behaviour and tissue development. *

Currently the standard method to prepare plant tissue to serve as a biocompatible scaffold is to decellularize it with serial chemical treatment.*

In their article “Supercritical carbon dioxide decellularization of plant material to generate 3D biocompatible scaffolds” Ashlee F. Harris, Jerome Lacombe, Sumedha Liyanage, Margaret Y. Han, Emily Wallace, Sophia Karsunky, Noureddine Abidi and Frederic Zenhausern explore another method to produce biocompatible scaffolds.*

They use supercritical carbon dioxide (scCO2) together with 2% peracetic acid to decellularize plant material.*

Their subsequent investigations show that the process of decellularization, scaffold structure preservation and recellularization with human cells is less time consuming than with the standard chemical method.

In a further step the authors of the article describe how they use various scientific methods to evaluate the scaffolds they decellularized by the described scCO2 method.*

Ashlee F. Harris et al. use Atomic Force Microscopy (AFM) in order to find out if the scCO2 treatment had an impact on the mechanical properties of the scaffolds produced with this method.*

With AFM topography measurements they are able to establish that structures such as plant vasculature were preserved.*

The following determination of the Young’s Modulus calculated from multiple force curves of a homogeneous surface section of the produced scaffold shows it to be slightly lower than the one from a chemically decellularized scaffold.*

NANOSENSORS™ uniqprobe qp-BioAC AFM probes ( CB3 nominal values: 80 μm length, 30 μm mean width, 400 nm thickness, force constant 0.06 N/m, resonance frequency 30 kHz) were used for the scaffold measurements with Atomic Force Microscopy.

Figure 3 from “Supercritical carbon dioxide decellularization of plant material to generate 3D biocompatible scaffolds AFM imaging and spectrometry measurement” by Ashlee F. Harris et al.: 
They used AFM surface topography measurements to confirm that the structures such as plant vasculature were preserved after the scSO2 process and used  AFM force curves to calculate the  Young’s Modulus (YM) of the scCO2 decellularized scaffold. NANOSENSORS uniqprobe qp-BioAC AFM probes were used for the described AFM measurments. 
(a) Representative false colored three-dimensional surface mapping images and (b) Young’s modulus of scCO2 and chemically decellularized scaffolds (data as mean ± SEM; n = 5).
Figure 3 from “Supercritical carbon dioxide decellularization of plant material to generate 3D biocompatible scaffolds AFM imaging and spectrometry measurement” by Ashlee F. Harris et al.: (a) Representative false colored three-dimensional surface mapping images and (b) Young’s modulus of scCO2 and chemically decellularized scaffolds (data as mean ± SEM; n = 5).

While the scCo2 method promises to be a faster way to decellularize plant material and produce sterile and biocompatible scaffolds further research will be necessary to determine whether the differences the authors detected between the scaffolds produced with the scCO2 approach and the scaffolds produced with the chemical approach have a major influence on how repopulated cells behave in the achieved scaffolds.*

*Ashlee F. Harris, Jerome Lacombe, Sumedha Liyanage, Margaret Y. Han, Emily Wallace, Sophia Karsunky, Noureddine Abidi and Frederic Zenhausern
Supercritical carbon dioxide decellularization of plant material to generate 3D biocompatible scaffolds
Nature Scientific Reports 11, 3643 (2021)
DOI: https://doi.org/10.1038/s41598-021-83250-9

Please follow this external link to read the full article: https://rdcu.be/cAqW3

Open Access The article “Supercritical carbon dioxide decellularization of plant material to generate 3D biocompatible scaffolds” by Ashlee F. Harris, Jerome Lacombe, Sumedha Liyanage, Margaret Y. Han, Emily Wallace, Sophia Karsunky, Noureddine Abidi and Frederic Zenhausern 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 licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence 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 licence, visit http://creativecommons.org/licenses/by/4.0/.

Cytoskeletal disorganization underlies PABPN1-mediated myogenic disability

Muscle wasting is connected with changes in various cellular mechanisms that influence protein homeostasis, transcription, protein acetylation and different metabolic pathways. *

Scientific studies have shown that reduced levels of polyadenylation binding protein 1 ( PABPN1 , a multifactorial regulator of mRNA processing ) cause muscle wasting, including muscle atrophy, extracellular matrix thickening, myofiber typing transitions and central nucleation. *

However, the cellular mechanisms behind PABPN1-mediated muscle wasting are not fully understood. *

In the article “Cytoskeletal disorganization underlies PABPN1-mediated myogenic disability” Cyriel Sebastiaan Olie, Erik van der Wal, Cikes Domagoj, Loes Maton, Jessica C. de Greef, I.-Hsuan Lin, Yi-Fan Chen, Elsayad Kareem, Josef M. Penninger, Benedikt M. Kessler and Vered Raz examine the cytoskeletal auxiliary changes that are dependent on PABPN1 levels using 2D and 3D models, and investigate how these affect muscle wasting. *

They suggest that poor cytoskeletal mechanical features are caused by altered expression levels of cytoskeletal proteins and contribute to muscle wasting and atrophy. *

For the measurements of cell-mechanics properties in control and shPAB cells ( muscle cells with reduced PABPN1 levels ) the authors used Brillouin Light Scattering Microscopy and Atomic Force Microscopy. *

NANOSENSORS™ uniqprobe qp-BioAC ( CB3 ) AFM probes were used in the quantitative imaging where a force curve is applied at each point. The analyzed area of each cell was 5 µm × 5 µm (64 × 64 pixels) with an approach speed of 35 µm/s (3.4 ms/pixel), and applied forces of up to 118 pN. *

Figure 4 from “Cytoskeletal disorganization underlies PABPN1-mediated myogenic disability” by Cyriel Sebastiaan Olie et al.
 Disrupted cytoskeletal spatial organization in shPAB human muscle cell cultures. A Representative images of control and shPAB human muscle cell cultures, stained with antibodies to tubulin and actin, and the actin filaments were visualized with actin-GFP. B Tubulin staining in control and shPAB myoblast cell cultures after DMSO, 100 nM nocodazole or 25 nM paclitaxel treatment for 2 h. Scale bar is 25 µm. C Measurements of cell-mechanics properties in control and shPAB cells using the Brillouin Light Scattering Microscopy (Ci) or the Atomic Force Microscopy (Cii). Measurements were carried out in myoblasts; every dot represents the median from 1000 measurements in a cell. Cell stiffness is measured by GHz, and the young modulus reports the cell surface tension. Averages and standard deviations are from N = 15 cells. Statistical significance was calculated with the student’s t-test.
NANOSENSORS uniqprobe qp-BioAC ( CB3 ) AFM probes were used in the quantitative imaging of cell-mechanics properties.
Figure 4 from “Cytoskeletal disorganization underlies PABPN1-mediated myogenic disability” by Cyriel Sebastiaan Olie et al.
 Disrupted cytoskeletal spatial organization in shPAB human muscle cell cultures. A Representative images of control and shPAB human muscle cell cultures, stained with antibodies to tubulin and actin, and the actin filaments were visualized with actin-GFP. B Tubulin staining in control and shPAB myoblast cell cultures after DMSO, 100 nM nocodazole or 25 nM paclitaxel treatment for 2 h. Scale bar is 25 µm. C Measurements of cell-mechanics properties in control and shPAB cells using the Brillouin Light Scattering Microscopy (Ci) or the Atomic Force Microscopy (Cii). Measurements were carried out in myoblasts; every dot represents the median from 1000 measurements in a cell. Cell stiffness is measured by GHz, and the young modulus reports the cell surface tension. Averages and standard deviations are from N = 15 cells. Statistical significance was calculated with the student’s t-test.

*Cyriel Sebastiaan Olie, Erik van der Wal, Cikes Domagoj, Loes Maton, Jessica C. de Greef, I.-Hsuan Lin, Yi-Fan Chen, Elsayad Kareem, Josef M. Penninger, Benedikt M. Kessler & Vered Raz
Cytoskeletal disorganization underlies PABPN1-mediated myogenic disability
Nature Scientific Reports volume 10, Article number: 17621 (2020)
DOI: https://doi.org/10.1038/s41598-020-74676-8

Please follow this external link to read the full article https://rdcu.be/ceyJ4

Open Access: The article “Cytoskeletal disorganization underlies PABPN1-mediated myogenic disability” by Cyriel Sebastiaan Olie, Erik van der Wal, Cikes Domagoj, Loes Maton, Jessica C. de Greef, I.-Hsuan Lin, Yi-Fan Chen, Elsayad Kareem, Josef M. Penninger, Benedikt M. Kessler & Vered Raz 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/.