Tag Archives: 原子力显微镜

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/.

Happy Swiss National Holiday with Smallest Swiss Cross

We are celebrating today’s Swiss National Holiday courtesy of Basel University with the Smallest Swiss Cross – Made of 20 Single Atoms ( a NANOSENSORS PointProbePlus PPP-NCL AFM probe was used for this image)

20 bromine atoms positioned on a sodium chloride surface using the tip of an atomic force microscope at room temperature, creating a Swiss cross with the size of 5.6nm. The structure is stable at room temperature and was achieved by exchanging chlorine with bromine atoms. (Fig: University of Basel, Department of Physics) The image was taken using a NANOSENSORS PointProbePlus PPP-NCL AFM probe
20 bromine atoms positioned on a sodium chloride surface using the tip of an atomic force microscope at room temperature, creating a Swiss cross with the size of 5.6nm. The structure is stable at room temperature and was achieved by exchanging chlorine with bromine atoms. (Fig: University of Basel, Department of Physics)

In‐situ force measurement during nano‐indentation combined with Laue microdiffraction

A NANOSENSORS™ self-sensing self-activating Akiyama probe was used in a home-built Scanning Probe Microscope for this interesting research article.

*Florian Lauraux, Sarah Yehya, Stéphane Labat, Jean‐Sébastien Micha, Odile Robach, Oleg Kovalenko, Eugen Rabkin, Olivier Thomas, Thomas W. Cornelius
In‐situ force measurement during nano‐indentation combined with Laue microdiffraction
Nano Select , Volume2, Issue1, January 2021, Pages 99-106
DOI: https://doi.org/10.1002/nano.202000073

NANOSENSORS self-sensing and self-actuating Akiyama-probe AFM probe
NANOSENSORS self-sensing and self-actuating Akiyama-probe

Please have a look at the abstract below or follow the external link above to read the full article.

Abstract:

“For the characterization of the mechanical properties of materials the precise measurements of stress‐strain curves is indispensable. In situ nano‐mechanical testing setups, however, may lack the precision either in terms of strain or stress determination. Recently, the custom‐built scanning force microscope SFINX was developed which is compatible with third‐generation synchrotron end‐stations allowing for in situ nano‐mechanical tests in combination with nanofocused synchrotron x‐ray diffraction that is highly sensitive to strain and defects. The usage of a self‐actuating and self‐sensing cantilever tremendously increases the compactness of the system but lacks deflection sensitivity and, thus the force measurement. This deficiency is resolved by in situ monitoring the diffraction peaks of the Si cantilever by Laue microdiffraction during the nano‐indentation of a gold crystal. The orientation and, hence, the deflection of the Si cantilever is deduced from the displacement of the Si Laue spots on the detector giving force accuracies of better than 90 nN. At the same time, the dislocation density in the indented Au crystal is tracked by monitoring the Au Laue spots eventually resulting in complete stress‐dislocation density curves.”*

Open Access: The article “In‐situ force measurement during nano‐indentation combined with Laue microdiffraction” by Florian Lauraux, Sarah Yehya, Stéphane Labat, Jean‐Sébastien Micha, Odile Robach, Oleg Kovalenko, Eugen Rabkin, Olivier Thomas, Thomas W. Cornelius 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/.