Tag Archives: AFM Probes

A fibrin biofilm covers blood clots and protects from microbial invasion

New interesting publication by Macrea et. al mentioning the use of NANOSENSORS uniqprobe qp-BioAC:

“Hemostasis requires conversion of fibrinogen to fibrin fibers that generate a characteristic network, interact with blood cells, and initiate tissue repair. The fibrin network is porous and highly permeable, but the spatial arrangement of the external clot face is unknown. Here we show that fibrin transitioned to the blood-air interface through Langmuir film formation, producing a protective film confining clots in human and mouse models. We demonstrated that only fibrin is required for formation of the film, and that it occurred in vitro and in vivo. The fibrin film connected to the underlying clot network through tethering fibers. It was digested by plasmin, and formation of the film was prevented with surfactants. Functionally, the film retained blood cells and protected against penetration by bacterial pathogens in a murine model of dermal infection. Our data show a remarkable aspect of blood clotting in which fibrin forms a protective film covering the external surface of the clot, defending the organism against microbial invasion.”*

The AFM imaging and force measurements mentioned in this article were performed using CB3 of the NANOSENSORS™ uniqprobe qp-BioAC.

Supplemental Figure. 6. From Macrea et. al “A fibrin biofilm covers blood clots and protects from microbial invasion” Mechanisms and roles of fibrin film. A, Sneddon model used to calculate Young’s Modulus, where F is the force from the force curve, E is Young’s modulus, ν is Poisson’s ratio (0.5), α is the half angle for the indenter (15 degrees for our tips), and δ is the indentation. Note that this equation is only accurate with a half angle of 15 degrees for the first 200nm of indentation. B, Strength of the fibrin film in clots produced with plasma and thrombin with or without T101 (FXIII inhibitor ) investigated using atomic force microscopy (AFM). Fibrin fibres were visible under the film surface and these areas presented with stiffer Young’s modulus than fibrin film suspended between fibres. Grey lines in the zoomed-in images represent Young’s modulus scan area represented in the line force graphs. Scale bar - 2μm. C, Young’s Modulus was calculated for the suspended film and the film supported by fibers with and without T101 by fitting a Sneddon model to all AFM force curves found over the entire area that was imaged. 20 measurements were taken for each condition. **** P<0.0001. D, Clots produced from plasma with thrombin, under a layer of oil or enclosed in a ball of petroleum jelly, to eliminate the air - liquid interface, imaged by LSCM. Solid and dotted yellow lines indicate location of air liquid interface, n=3 experiments. Scale bars - 50μm. NANOSENSORS qp-BioAC AFM probes (CB3 ) were used for the AFM imaging and force measurements.
Supplemental Figure. 6. From Macrea et. al “A fibrin biofilm covers blood clots and protects from microbial invasion Mechanisms and roles of fibrin film. A, Sneddon model used to calculate Young’s Modulus, where F is the force from the force curve, E is Young’s modulus, ν is Poisson’s ratio (0.5), α is the half angle for the indenter (15 degrees for our tips), and δ is the indentation. Note that this equation is only accurate with a half angle of 15 degrees for the first 200nm of indentation. B, Strength of the fibrin film in clots produced with plasma and thrombin with or without T101 (FXIII inhibitor ) investigated using atomic force microscopy (AFM). Fibrin fibres were visible under the film surface and these areas presented with stiffer Young’s modulus than fibrin film suspended between fibres. Grey lines in the zoomed-in images represent Young’s modulus scan area represented in the line force graphs. Scale bar – 2μm. C, Young’s Modulus was calculated for the suspended film and the film supported by fibers with and without T101 by fitting a Sneddon model to all AFM force curves found over the entire area that was imaged. 20 measurements were taken for each condition. **** P<0.0001. D, Clots produced from plasma with thrombin, under a layer of oil or enclosed in a ball of petroleum jelly, to eliminate the air – liquid interface, imaged by LSCM. Solid and dotted yellow lines indicate location of air liquid interface, n=3 experiments. Scale bars – 50μm.

*Fraser L. Macrae, Cédric Duval, Praveen Papareddy, Stephen R. Baker, Nadira Yuldasheva, Katherine J. Kearney, Helen R. McPherson, Nathan Asquith, Joke Konings, Alessandro Casini, Jay L. Degen, Simon D. Connell,  Helen Philippou, Alisa S. Wolberg, Heiko Herwald, Robert A.S. Ariëns
A fibrin biofilm covers blood clots and protects from microbial invasion
Journal of  Clinical Investigation. 2018;128(8):3356-3368
DOI: https://doi.org/10.1172/JCI98734

Please follow this external link for the full article: https://www.jci.org/articles/view/98734#sd

The article “A fibrin biofilm covers blood clots and protects from microbial invasion” by Fraser L. Macrae et. al is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/ licenses/by/4.0/.

See you at AVS in Long Beach CA today

Meet our CEO this week at AVS 65th International Symposium and Exhibition in Long Beach CA.

Manfred Detterbeck at AVS 65th International Symposium and Exhibition.
Manfred Detterbeck at AVS 65th International Symposium and Exhibition. Great AVS T-Shirt!

 

Long Beach Convention Center venue of AVS 65th International Symposium and Exhibition
Another beautiful day outside Long Beach Convention Center – venue of this year’s AVS International Symposium and Exhibition.

Resonant torsion magnetometry in anisotropic quantum materials

Who said that AFM probes can only be used for Atomic Force Microscopy?

In the article “Resonant torsion magnetometry in anisotropic quantum materials” which just appeared in Nature Communications, K. A. Modic, Maja D. Bachmann, B. J. Ramshaw, F. Arnold, K. R. Shirer, Amelia Estry, J. B. Betts, Nirmal J. Ghimire, E. D. Bauer, Marcus Schmidt, Michael Baenitz, E. Svanidze, Ross D. McDonald, Arkady Shekhter and Philip J. W. Moll use the NANOSENSORS™ Akiyama-probe for resonant torsion magnetometry.

Figure 1 from "Resonant torsion magnetometry in anisotropic quantum materials": Schematic overview of resonant torsion magnetometry. a First and second derivatives of the free energy with respect to the magnetic field B and the field orientation θ. b The quartz tuning fork of the Akiyama A-probe (http://www.akiyamaprobe.com) is electrically excited at the lowest-resonance mode of the silicon cantilever, producing a large out-of-plane motion at the tip of the cantilever. c Schematic representing the principle of measuring the magnetotropic coefficient k. In a magnetic field, the magnetic torque brings the lever to a new equilibrium position. The magnetic energy of the samples changes the effective stiffness of the lever, leading to a shift in the resonant frequency. d The silicon cantilever glued to each leg of the quartz tuning fork with a single crystal of RuCl3 mounted at the tip with Bayer silicone grease
Figure 1 from “Resonant torsion magnetometry in anisotropic quantum materials”: Schematic overview of resonant torsion magnetometry a First and second derivatives of the free energy with respect to the magnetic field B and the field orientation θ. b The quartz tuning fork of the Akiyama A-probe (http://www.akiyamaprobe.com) is electrically excited at the lowest-resonance mode of the silicon cantilever, producing a large out-of-plane motion at the tip of the cantilever. c Schematic representing the principle of measuring the magnetotropic coefficient k. In a magnetic field, the magnetic torque brings the lever to a new equilibrium position. The magnetic energy of the samples changes the effective stiffness of the lever, leading to a shift in the resonant frequency. d The silicon cantilever glued to each leg of the quartz tuning fork with a single crystal of RuCl3 mounted at the tip with Bayer silicone grease

There are three advantages why it makes sense to divert the NANOSENSORS™ Akiyama-probe from it’s orginal intended use and use it for resonant torque magnetometry instead:

1. the relatively large spring constant of the silicon cantilever allows the authors to extend ultrasensitive and dynamic cantilever magnetometry to macroscopic sample sizes

  1. “the placement of the sample on the silicon cantilever (rather than one leg of a quartz tuning fork) eliminates complications that arise from the center of mass motion of the tuning fork coupling to the resonance mode

3. the electrical read-out of the A-probe eliminates the need for optical detection of the resonant frequency, thus making setup relatively straightforward and more robust compared to previous approaches.”*

*K. A. Modic, Maja D. Bachmann, B. J. Ramshaw, F. Arnold, K. R. Shirer, Amelia Estry, J. B. Betts, Nirmal J. Ghimire, E. D. Bauer, Marcus Schmidt, Michael Baenitz, E. Svanidze, Ross D. McDonald, Arkady Shekhter; Philip J. W. Moll
Resonant torsion magnetometry in anisotropic quantum materials
Nature Communications, volume 9, Article number: 3975 (2018)
DOI: https://doi.org/10.1038/s41467-018-06412-w

For the full article please follow this external link: https://rdcu.be/7Z0A

Open Access The article “Resonant torsion magnetometry in anisotropic quantum materials” by K.A. Modic et. al 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/.