Tag Archives: biology

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/.

MAC Mode Cantilevers for Keysight, Agilent and Molecular Imaging AFMs now available from NANOSENSORS

Do you have a Keysight, Agilent or Molecular Imaging Atomic Force Microscope in your lab? Are you using MAC Mode (Keysight Technologies’ patented magnetic AC mode ) to image soft samples or for imaging in fluids?
Then NANOSENSORS™ has the right cantilevers for you.

MAC mode imaging of lambda phage DNA in a buffer solution. Image courtesy of Keysight Technologies
MAC mode imaging of lambda phage DNA in a buffer solution. Image courtesy of Keysight Technologies

On the NANOSENSORS Special Developments List you will find all the cantilevers you need to continue working with MAC Mode.

Keysight TYPE II MAC Levers (PN: N9812x) – NANOSENSORS special development code: SD-MAC-Type2

Keysight TYPE VII MAC Levers (PN: N9866x) – NANOSENSORS special development code: SD-MAC-Type7

Keysight TYPE VIII MAC Levers (PN: N9867x) – NANOSENSORS special development code: SD-MAC-Type8

Keysight TYPE IX MAC Levers (PN: N9811x) – NANOSENSORS special development code: SD-MAC-Type9

MAC Mode Cantilevers for Keysight, Agilent and Molecular Imaging Atomic Force Microscopy
MAC Mode Cantilevers for Keysight, Agilent and Molecular Imaging Scanning Probe Microscopes

Zn2+-triggered self-assembly of Gonadorelin [6-D-Phe] to produce nanostructures and fibrils

For this article the AFM images taken with tapping mode in Tris buffer solution were performed with the NANOSENSORS qp-BioAC (cantilever 3, resonance frequency 30kHz).

Figure 5 from Yordanova et. al. "Zn2+-triggered self-assembly of Gonadorelin [6-D-Phe] to produce nanostructures and fibrils" - AFM image of the Zn2+: GnRH [6-D-Phe] 10:1 complex. (a,b) Oligomers after preparation with tapping mode in Tris buffer solution (c,d) fibrils with tapping mode in air (z-scale indicates the average size of the formed oligomers and fibrils). NANOSENSORS qp-BioAC AFM probe was used to perform images in buffer solution
Figure 5 from Yordanova et. al. “Zn2+-triggered self-assembly of Gonadorelin [6-D-Phe] to produce nanostructures and fibrils” – AFM image of the Zn2+: GnRH [6-D-Phe] 10:1 complex. (a,b) Oligomers after preparation with tapping mode in Tris buffer solution (c,d) fibrils with tapping mode in air (z-scale indicates the average size of the formed oligomers and fibrils).

Yordanka Yordanova, Willem Vanderlinden, Raphael Stoll, Daniel Rüdiger, Andreas Tosstorff, Wolfgang Zaremba, Gerhard Winter, Stefan Zahler & Wolfgang Friess
Zn2+-triggered self-assembly of Gonadorelin [6-D-Phe] to produce nanostructures and fibrils
Nature Scientific Reports volume 8, Article number: 11280 (2018)
doi: https://doi.org/10.1038/s41598-018-29529-w
Please follow this external link to read the full article on the  Nature website: https://rdcu.be/4y9J

Abstract: A synthetic derivative, GnRH [6-D-Phe], stable against enzymatic degradation, self-assembles and forms nanostructures and fibrils upon a pH shift in the presence of different concentrations of Zn2+ in vitro. Attenuated Total Reflection Fourier Transform Infrared spectroscopy (ATR–FTIR) revealed the existence of higher order assembly of Zn2+: GnRH [6-D-Phe]. Nuclear Magnetic Resonance spectroscopy (NMR) indicated a weak interaction between Zn2+ and GnRH [6-D-Phe]. Atomic Force Microscopy (AFM) showed the existence of GnRH [6-D-Phe] oligomers and fibrils. Molecular Dynamic (MD) simulation of the 10:1 Zn2+: GnRH [6-D-Phe] explored the interaction and dimerization processes. In contrast to already existing short peptide fibrils, GnRH [6-D-Phe] nanostructures and fibrils form in a Tris-buffered pH environment in a controlled manner through a temperature reduction and a pH shift. The lyophilized Zn2+: GnRH [6-D-Phe] assembly was tested as a platform for the sustained delivery of GnRH [6-D-Phe] and incorporated into two different oil vehicle matrices. The in vitro release was slow and continuous over 14 days and not influenced by the oil matrix.

The article “Zn2+-triggered self-assembly of Gonadorelin [6-D-Phe] to produce nanostructures and fibrils” by Yordanova Y. et al. is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/