scholarly journals Atomic Force Microscopy for the Evaluation of Corneal Surface Roughness after Femtosecond Laser Flap Creation and Excimer Ablation.

2021 ◽  
Author(s):  
Rafael Cañones-Zafra ◽  
Juan Gros-Otero ◽  
Montserrat Garcia-Gonzalez ◽  
Santiago Casado ◽  
Samira Ketabi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Femtosecond Laser ◽  
Corneal Stroma ◽  
Central Area ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging ◽  
Corneal Sample ◽  
20 Nm ◽  
Flap Creation

Abstract Introduction: It is well known that the femtosecond laser lamellar cut has some degree of roughness. Nevertheless, as in femtosecond laser assisted LASIK (FS-LASIK), an excimer LASIK ablation is performed, the post-ablation stromal bed should show a marked decrease in roughness. We decided to compare, using atomic force microscopy (AFM), the roughness of the corneal stromal bed, after a Femtosecond lasers device (FS) flap was created with or without an excimer myopic ablation.Methods: Using 6 freshly enucleated porcine eyes, we created in every eye a flap using a femtosecond laser. Additionally in 3 eyes an excimer laser ablation to correct -3 diopters (D) was made. AFM imaging of the remaining corneal stroma was performed. Ten different square areas of 20μm x 20μm at the central area of the stroma of each corneal sample were studied. The roughness parameters used was the root-mean-square (RMS) deviation from a perfectly flap plane.Results: The RMS deviation were 360 ± 120 nm in femtosecond laser only, and 110 ± 20 nm in those cases where excimer is also involved (p<0.0001).Conclusions: Our results show that the roughness of the surface treated with excimer is clearly lower than in the group with no excimer ablation, thus the application of laser excimer after a flap creation by femtosecond laser flap creation may soften the nano-irregularities created by this technique.

scholarly journals Corneal stromal roughness after VisuMax and Intralase femtosecond laser photodisruption: An atomic force microscopy study

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252449
Author(s):  
Juan Gros-Otero ◽  
Samira Ketabi ◽  
Rafael Cañones-Zafra ◽  
Montserrat Garcia-Gonzalez ◽  
Cesar Villa-Collar ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Femtosecond Laser ◽  
Microscopy Study ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Significant Difference ◽  
Surface Measurements ◽  
Bed Roughness ◽  
Flap Creation

Purpose To compare the induced corneal stromal bed roughness measured with atomic force microscopy (AFM) after LASIK flap creation with the IntraLase 60 kHz and the VisuMax femtosecond laser platforms. Methods Three freshly enucleated porcine eyes were operated with each femtosecond laser in this experimental study. Standard LASIK treatment parameters were used for the experiment. After LASIK flap creation, the corneal stromal roughness was assessed using a JPK NanoWizard II® AFM in contact mode immersed in liquid. Olympus OMCL-RC800PSA commercial silicon nitride cantilever tips were used. Surface measurements were made in 10 regions of the central cornea of each sample measuring 20 x 20 microns, at 512 x 512 point resolution. Roughness was measured using the root-mean-square (RMS) value within the given regions. Results Measurements from 30 regions of the 3 eyes (10 measurements per eye) in the Intralase (FS1) group, and 30 regions of the 3 eyes (10 measurements per eye) in the VisuMax (FS2) group were analyzed. There was a statistically significant difference in mean ± standard deviation RMS values between the FS1 and the FS2 groups (360 ± 120 versus 230 ± 100 nm respectively; P< 0.00001). Conclusion This AFM study indicates that the surface of the stromal bed after LASIK flap creation is smoother in the FS2 group than the FS1 group.

Femtosecond Laser Photodisruptive Effects on the Posterior Human Corneal Stroma Investigated with Atomic Force Microscopy

2012 ◽  
Vol 22 (7_suppl) ◽  
pp. 89-97 ◽  
Author(s):  
Sebastiano Serrao ◽  
Marco Lombardo ◽  
Maria P. De Santo ◽  
Giuseppe Lombardo ◽  
Domenico Schiano Lomoriello ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Femtosecond Laser ◽  
Corneal Stroma ◽  
Force Microscopy ◽  
Atomic Force

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

scholarly journals Atomic force microscopy analysis of native infectious and inactivated SARS-CoV-2 virions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sébastien Lyonnais ◽  
Mathilde Hénaut ◽  
Aymeric Neyret ◽  
Peggy Merida ◽  
Chantal Cazevieille ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Native Conformation ◽  
Force Microscopy ◽  
Enveloped Virus ◽  
Atomic Force ◽  
Afm Imaging ◽  
Level 3 ◽  
Microscopy Analysis ◽  
Virus Morphology ◽  
Nanoscale Level

AbstractSARS-CoV-2 is an enveloped virus responsible for the Coronavirus Disease 2019 (COVID-19) pandemic. Here, single viruses were analyzed by atomic force microscopy (AFM) operating directly in a level 3 biosafety (BSL3) facility, which appeared as a fast and powerful method to assess at the nanoscale level and in 3D infectious virus morphology in its native conformation, or upon inactivation treatments. AFM imaging reveals structurally intact infectious and inactivated SARS-CoV-2 upon low concentration of formaldehyde treatment. This protocol combining AFM and plaque assays allows the preparation of intact inactivated SARS-CoV-2 particles for safe use of samples out of level 3 laboratory to accelerate researches against the COVID-19 pandemic. Overall, we illustrate how adapted BSL3-AFM is a remarkable toolbox for rapid and direct virus analysis based on nanoscale morphology.

Atomic force microscopy (AFM) imaging suggests that stromal interaction molecule 1 (STIM1) binds to Orai1 with sixfold symmetry

FEBS Letters ◽  
2014 ◽  
Vol 588 (17) ◽  
pp. 2874-2880 ◽  
Author(s):  
Dilshan Balasuriya ◽  
Shyam Srivats ◽  
Ruth D. Murrell-Lagnado ◽  
J. Michael Edwardson
Keyword(s):  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
Stromal Interaction Molecule 1 ◽  
Atomic Force ◽  
Afm Imaging ◽  
Sixfold Symmetry

Imaging of Xenopus laevis Oocyte Plasma Membrane in Physiological-Like Conditions by Atomic Force Microscopy

2013 ◽  
Vol 19 (5) ◽  
pp. 1358-1363 ◽  
Author(s):  
Massimo Santacroce ◽  
Federica Daniele ◽  
Andrea Cremona ◽  
Diletta Scaccabarozzi ◽  
Michela Castagna ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Plasma Membrane ◽  
High Resolution ◽  
Membrane Proteins ◽  
Xenopus Laevis ◽  
Functional Study ◽  
Xenopus Laevis Oocyte ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

AbstractXenopus laevis oocytes are an interesting model for the study of many developmental mechanisms because of their dimensions and the ease with which they can be manipulated. In addition, they are widely employed systems for the expression and functional study of heterologous proteins, which can be expressed with high efficiency on their plasma membrane. Here we applied atomic force microscopy (AFM) to the study of the plasma membrane of X. laevis oocytes. In particular, we developed and optimized a new sample preparation protocol, based on the purification of plasma membranes by ultracentrifugation on a sucrose gradient, to perform a high-resolution AFM imaging of X. laevis oocyte plasma membrane in physiological-like conditions. Reproducible AFM topographs allowed visualization and dimensional characterization of membrane patches, whose height corresponds to a single lipid bilayer, as well as the presence of nanometer structures embedded in the plasma membrane and identified as native membrane proteins. The described method appears to be an applicable tool for performing high-resolution AFM imaging of X. laevis oocyte plasma membrane in a physiological-like environment, thus opening promising perspectives for studying in situ cloned membrane proteins of relevant biomedical/pharmacological interest expressed in this biological system.

ATOMIC FORCE MICROSCOPY AND XRD ANALYSIS OF SILVER FILMS DEPOSITED BY THERMAL EVAPORATION

2006 ◽  
Vol 20 (02) ◽  
pp. 217-231 ◽  
Author(s):  
MUHAMMAD MAQBOOL ◽  
TAHIRZEB KHAN
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Size ◽  
Surface Characterization ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Xrd Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Average Grain Size ◽  
20 Nm

Thin films of pure silver were deposited on glass substrate by thermal evaporation process at room temperature. Surface characterization of the films was performed using X-ray diffraction (XRD) and atomic force microscopy (AFM). Thickness of the films varied between 20 nm and 72.8 nm. XRD analysis provided a sharp peak at 38.75° from silver. These results indicated that the films deposited on glass substrates at room temperature are crystalline. Three-dimension and top view pictures of the films were obtained by AFM to study the grain size and its dependency on various factors. Average grain size increased with the thickness of the deposited films. A minimum grain size of 8 nm was obtained for 20 nm thick films, reaching 41.9 nm when the film size reaches 60 nm. Grain size was calculated from the information provided by the XRD spectrum and averaging method. We could not find any sequential variation in the grain size with the growth rate.

Atomic Force Microscopy (AFM) Imaging and Force Recognition at the Molecular Level in Bacteria

2004 ◽  
Vol 10 (S02) ◽  
pp. 1094-1095
Author(s):  
David P. Allison ◽  
Claretta J. Sullivan ◽  
Jennifer L. Morrell ◽  
Peter R. Hoyt ◽  
Mitchel J. Doktycz
Keyword(s):  
Atomic Force Microscopy ◽  
Molecular Level ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

scholarly journals Особенности наноструктурирования поверхности кремния в результате ее сверхбыстрого нагрева фемтосекундным лазерным импульсом в воде

2018 ◽  
Vol 44 (14) ◽  
pp. 58
Author(s):  
С.А. Ромашевский
Keyword(s):  
Atomic Force Microscopy ◽  
Laser Pulse ◽  
Femtosecond Laser ◽  
Surface Morphology ◽  
Silicon Surface ◽  
Ablation Threshold ◽  
Water Environment ◽  
Force Microscopy ◽  
Atomic Force ◽  
Minimum Depth

AbstractSilicon surface morphology induced by a femtosecond laser pulse at near-threshold fluences in water environment is investigated by means of atomic-force microscopy (AFM). With increasing fluence, the silicon surface transforms into nanoscale ring-shaped and blister structures, as well as smooth and nanostructured microcraters with a minimum depth of 1 nm. The formation of starlike patterns imprinted at the surface of microcraters at fluences above the ablation threshold is observed.

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