Name: atomic force microscopy for surface mapping
Uploaded: 2023-04-30T12:00:37.000Z
Duration: 1 min 8 s
Channel: JoVE

Die Rasterkraftmikroskopie (Rasterkraftmikroskopie) oder Rasterkraftmikroskopie (Rasterkraftmikroskopie) erzeugt ein Bild mit einer Nanosonde, um topografische Informationen über eine Probe mit Nanometerauflösung zu liefern.
Während ein optisches Mikroskop bis zu 1000-fach vergrößern kann, beträgt das Vergrößerungspotenzial des Rasterfelds bis zu 1.000.000-fach.
Das AFM kann Bilder sowohl von fixierten als auch von lebenden Proben erstellen, wodurch es dynamische zelluläre Prozesse wie die Aktindynamik erfassen kann.
Die AFM-Nanosonde wird am Ende eines flexiblen Auslegers befestigt und gemeinsam scannen sie die Probe. Die Sonde folgt den Konturen der Probenoberfläche, bewegt sich auf und ab, wodurch der Ausleger verschoben wird.
Bei einer Art von AFM wird ein Laserstrahl auf den Ausleger gerichtet, und während er sich bewegt, bewegt sich auch die Reflexion des Lasers.
Ein positionsempfindlicher Photodetektor erfasst die Ablenkung des Laserstrahls.
Die Daten werden an einen Computer gesendet, wo sie von einer Software verarbeitet werden können, um ein dreidimensionales Bild der Probenoberfläche zu erzeugen.

<ol>
	<li>Casuso, Ignacio, Felix Rico und Simon Scheuring. "Biologisches AFM: woher wir kommen – wo wir sind – wohin wir gehen können." Zeitschrift für molekulare Erkennung 24.3 (2011): 406-413.</li>
	<li>Garcıa, Ricardo und Ruben Perez. "Dynamische Rasterkraftmikroskopiemethoden." Surface Science Reports 47.6-8 (2002): 197-301.</li>
</ol>

rasterkraftmikroskopie

Atomic Force Microscopy

Die Rasterkraftmikroskopie (AFM) ist eine Art Rastersondenmikroskopie, mit der topografische Details verschiedener Proben wie Keramik, Glas, Polymere und biologische Proben analysiert werden können. AFM bietet eine über 1000-mal höhere Auflösung als das optische Bildgebungssystem. Mit AFM erzeugte Bilder sind dreidimensionale Oberflächenprofile und bieten einen Vorteil gegenüber den flachen, zweidimensionalen Bildern anderer Bildgebungstechniken.

Die AFM-Sonde

Die Sonde gilt als das Herzstück jedes AFM-Aufbaus und besteht aus der Cantilever- und Spitzenbaugruppe. Sonden sind bei diesem Mikroskoptyp das am häufigsten ausgetauschte Teil, da die Spitze durch die ständige Interaktion mit den Proben abgenutzt wird. Daher hängt die Wahl des Materials für die Sonde von den Eigenschaften der Probe ab. Siliziumsonden, die zur Analyse harter Proben verwendet werden, sind steifer und schärfer als Siliziumnitridsonden, die sich besser zum Scannen weicherer Proben eignen. Diese scharfen Spitzen werden durch elektrochemisches Ätzen oder Kohlenstoffnanoröhren für eine genauere Analyse hergestellt.

Bildgebungsmodi von AFM

Beim AFM wird die Oberflächentopographie mithilfe der Wechselwirkung zwischen der Sondenspitze und der Probenoberfläche untersucht. Es gibt zwei Hauptbildgebungsmodi: einen statischen Modus, der auch als Kontaktmodus bezeichnet wird, und einen dynamischen Modus.

Im statischen oder Kontaktmodus steht die Sondenspitze in ständigem Kontakt mit der Probenoberfläche. Während die Spitze über die Oberfläche schleift, führen Abstoßungskräfte zwischen der Probe und der Spitze zu einer Biegung des Auslegers, die aufgezeichnet wird. Die gesamte Probenoberfläche wird sowohl in der X- als auch in der Y-Achse hin und her gescannt, was als Rasterscannen bezeichnet wird, während die vertikale Bewegung des Auslegers die Z-Achse aufzeichnet und so ein 3D-Bild erzeugt.

Im dynamischen Modus schwingt die Sonde knapp über der Probenoberfläche und kommt der Oberfläche nahe, berührt sie jedoch nicht. Anziehende und abstoßende Kräfte bestimmen die Variation des Abstands zwischen der Spitze und der Probe und beeinflussen die Amplitude der Cantilever-Schwingung. Dieses Feedback wird aufgezeichnet, um die Oberflächentopographie der Probe zu konstruieren.

Rasterkraftmikroskopie

Die Rasterkraftmikroskopie (AFM) ist eine Art der Rastersondenmikroskopie, mit der topographische Details verschiedener Proben wie Keramik, Glas, ...

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Cell Biology

Zellbiologie

Unit 1

Einheit 1

Visualizing Cells, Tissues, and Molecules

Visualisierung von Zellen, Geweben und Molekülen

KEY TERMS AND CONCEPTS

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atomic force microscopy for surface mapping

Atomic force microscopy is used to map the surface details of materials. It can examine ceramics, glass, polymers, and biological samples. The method gives far more resolution than an optical imaging system and produces three-dimensional surface profiles instead of flat 2D images.

The probe is the key part of an AFM setup. It includes the cantilever and tip assembly, and it is also the part that is replaced most often. Constant contact with samples wears down the tip, so probe choice depends on the sample being scanned. Silicon probes are stiffer and sharper, which makes them useful for hard samples. Silicon nitride probes are better for softer samples.

AFM tips can be made with electrochemical etching or with carbon nanotubes to improve accuracy. The microscope reads surface topography by tracking how the probe tip interacts with the sample surface. This interaction is recorded as the probe scans across the surface.

AFM uses two main imaging modes. In static mode, also called contact mode, the tip stays in continuous contact with the surface. As it drags across the sample, repulsive forces bend the cantilever, and that bending is recorded. The sample is scanned back and forth in the x- and y-axes, which is called raster scanning, while the vertical motion of the cantilever records the z-axis and builds a 3D image.

In dynamic mode, the probe oscillates just above the sample surface. It comes close to the surface without touching it. Attractive and repulsive forces change the distance between the tip and the sample and affect the oscillation amplitude. That feedback is then used to construct the surface topography.

Atomic Force Microscopy for Surface Mapping

atomic-force-microscopy-for-surface-mapping

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atomic force microscopy

Atomic force microscopy is used to map the surface details of materials. It can examine ceramics, glass, polymers, and biological samples. The method gives far more resolution than an optical imaging system and produces three-dimensional surface profiles instead of flat 2D images. The probe is the key part of an AFM setup. It includes the cantilever and tip assembly, and it is also the part that is replaced most often. Constant contact with samples wears down the tip, so probe choice depends...

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key terms and concepts

Learn how atomic force microscopy maps surfaces, why probe choice matters, and how contact and dynamic modes build detailed 3D images of samples.

Atomic Force Microscopy for Surface Mapping | JoVE K12

cell biology

JoVE Core Zellbiologie veranschaulicht komplexe zelluläre Prozesse in leicht verständlichen und dennoch umfassenden animierten Videolektionen. Diese Sammlung konzentriert sich auf die wesentlichen Bestandteile und Funktionen von Zellen, einschließlich Organellen und Membranen, Zelltransport und Zellenergie. Ergänzt wird sie durch Videos von Wissenschaftlern in Aktion, die die Anwendung der Zellbiologie in realen Forschungsexperimenten demonstrieren.

Atomic Force Microscopy for Surface Mapping

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