Case StudyA5 Science - Nanoscale Explorers
Welcome to our case study section.
Here we present concrete results of the work carried out by AFM in various applications. From materials science to biology, semiconductor and surface analysis, these examples demonstrate the quality of our protocols and the resolution of our products and services.
Explore this page to discover how atomic force microscopy and our teams can help you to get scientific evidence.
Bacterial strain Escherichia coli cells
immobilized on a glass slide (3D view)
Study of Protein: Characterization of a G protein-coupled receptor by single molecule force spectroscopy
Category: Health, Pharma
G protein-coupled receptors (GPCRs) are an essential class of therapeutic targets associated with a wide range of biological and cellular functions.
Located in the plasma membrane at the surface of cells, GPCRs bind to a variety of ligands, such as hormones, nucleotides, lipids, ions, and neurotransmitters. Therefore, receptors of the GPCR family are key intermediaries in biological signaling mechanisms and allow the development of new pharmacological pathways.
In this research field, atomic force microscopy provides a unique characterization of these receptors: by using the single molecule force spectroscopy mode, we have the ability to unfold the receptor when they are still anchored in the cell membrane. In this configuration, we can measure the force required to complete the deployment of the protein in order to obtain information regarding the structure of the molecule.
The force curve obtained for each unfolded protein reveals a characteristic signature: then the mathematical analysis of this signal informs about the protein’s secondary and tertiary structure, its potential for oligomerization, and the orientation of the studied receptor.
To make these observations, our protocols are specifically adapted to the nature of the sample: in this case, the proteins are studied under physiological conditions without any denaturation step.
Characterization of G protein-coupled receptors expressed on the surface of a proteoliposome. (Top) Height images at different resolutions of a proteoliposome sample fused onto a thin layer of mica and containing the protein of interest, the white dashed line materializes the location of the horizontal section measured and presented in the bottom left of the figure. (Bottom left) Topographic measurements that present the height of the section measured at the surface of the sample. (Bottom right) Unfolding profiles observed by single molecule force spectroscopy and illustration of the principle of this technology.
Study of Cardiac Cells: Evaluation of biological response to treatment by force spectroscopy
Category: Health, Cardiology
The development of new therapeutic molecules begins with observations and research conducted in vivo to determine the effects of treatment and evaluate the toxicity on organisms.
For instance, atomic force microscopy used with force spectroscopy mode allows for the comparison of the biological response and the integrity of living cardiomyocytes exposed to new molecules of interest. Cardiomyocytes are the cells that make up the heart muscle and are now studied for their critical roles in cardiac muscle contraction and associated pathologies.
Observations made in the laboratory reveal the unique topography of the cardiomyocyte membrane, an ordered structure formed of hollow and crest. Once the cell is exposed to new physicochemical conditions, the external structure of the cell is altered. This disorganization is accompanied by a loss of elasticity of the cell membrane. These morphological and mechanical changes are the early signs that occur during cell necrosis.
Today, atomic force microscopy is one of the most powerful tools for the observation and quantification of the effects of therapeutic molecules on living cells.
Comparison of the structural properties of the lateral membrane of cardiomyocytes under control conditions and after the therapeutic treatment. (Top) Optical microscopy picture of an isolated adult cardiomyocyte (CM).
(Left) Image and elasticity map of the surface of a CM membrane under control conditions, recorded by force spectroscopy. (Right) Image and elasticity map of the surface of a CM membrane after the therapeutic treatment.
Study of Microorganisms: Quantitative measurements of the effects of physicochemical conditions on Bacterial Cell Structure
Category: Processes, Environment
Atomic force microscopy allows for nano-indentation measurements at the single living cell scale.
When combined with appropriate sample preparation and immobilization protocols, this technology provides access to information regarding the biomechanical properties of cells in liquid conditions. The elasticity of the cell envelope, resistance to stress, surface roughness and adhesion are the primary characteristics that determine the behaviors of these biological particles.
Morphological and nanomechanical characteristics of cells are studied to measure and understand biological adaptation mechanisms in response to stress, physical constraints, antibiotics, or a specific physicochemical environment. For example, in the case of bacterial cells, we investigate in the laboratory the first effects on the cell wall of a low-concentration antibiotic solution.
These analyses have shown the resistance of bacteria cells to these new physicochemical conditions, as the morphology of the cell and dimensions are not altered by the treatment. However, once nanomechanical parameters are measured, a difference in the elasticity of the bacterial cell envelope is observed, inducing a significant modification of the ability of the bacteria cells to deform and thus resist mechanical constraints.
These observations quantify the structural modifications adopted by the cell in response to stress and thus improve our understanding of the mechanisms of action of antibiotic molecules. The quantitative data obtained are also used to construct simulation models dedicated to studying the compression and deformation of biological cells.
Observation of the effects of exposure to a low concentration of antibiotics on the structure of the E. coli cell. (Top left) Height image of an E. coli cell obtained under control conditions. (Top right) Image obtained after treatment.
(Bottom left) Principle of elasticity measurements according to a matrix of points on the sample surface. Elasticity maps are measured for each condition.
(Bottom right) While the general structure of the bacterial cell is not affected, the measured elasticity values demonstrate the initial effects of treatment on the cell wall.
Study of Surface: Measurement of degradation of coatings used in aerospace materials
Category: Surface, Coating
Protection against corrosion is crucial to ensure the reliability and durability of equipment in many industrial sectors. For example, in the aerospace industry, some coatings are developed to protect surfaces from the UV radiation emitted by the Sun.
Atomic force microscopy is the most suitable nanoscale analysis method for the study of materials and surface treatments, as it allows observation and measurement of roughness and adhesion properties, coating quality and defects, or corrosion development.
Tests are conducted in the laboratory under controlled conditions without damaging the analyzed surfac. We compare the topography and roughness of different coatings after exposure to corrosive conditions. The results demonstrate that the least affected surface after this event is the one treated with a specific coating. Cross-sections expose multiple irregularities present on the material surface and the proportions of damage incurred in depth.
These analyses are integrated into the development of more resistant and high-performance coatings for the aerospace industry.
Comparative study of the topography and roughness of different coatings after a corrosive event. (Top) Roughness map and cross-section of a surface with coating A, the most resistant. (Middle) Roughness map and cross-section of a surface with coating B: detection of surface defects. (Bottom) Roughness map and cross-section of a surface with coating C: increase in roughness.
Study of Nanostructures: Topography and morphology of surfaces in three dimensions
Category: Nanotechnology, 3D
Biochips and nanoprocessors are miniaturized information processing devices at the interface between electronics and biology that are being developed for use in medical innovation, information technology, energy, and communications.
Their advantages come for the significant improvement of device capabilities while limiting the use of resources and raw materials, so the precision of fabrication of these nanotechnologies is crucial for their performance and reliability.
Atomic force microscopy is a recommended tool for studying surfaces and interfaces because it allows for precise measurement of the three-dimensional dimensions of nanostructures. In the laboratory, our protocols are developed to control the shape and integrity of surface structures with a resolution below the nanometer, in order to provide high-resolution images and 3D projections.
To accurately measure the dimensions of nanostructures, atomic force microscopy is used to scan objects in different directions of the plane. Additionally, this technology can be considered for the manipulation and assembly of objects at the atomic scale.
Topographical representations of nanostructures and measured cross-sections. Atomic force microscopy reveals the smallest dimensions: in this example, the geometries exposed on the analyzed surfaces are between 1 and 200 nm.
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