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

Mikroskopia sił atomowych lub AFM generuje obraz za pomocą nanosondy, aby dostarczyć informacji topograficznych o próbce z rozdzielczością nanometrów.
Podczas gdy mikroskop optyczny może powiększać do 1000x, potencjał powiększenia AFM wynosi do 1 000 000x.
AFM może tworzyć obrazy zarówno stałych, jak i żywych próbek, co pozwala na uchwycenie dynamicznych procesów komórkowych, takich jak dynamika aktyny.
Nanosonda AFM jest przymocowana do końca elastycznego wspornika i razem skanują próbkę. Sonda podąża za konturami powierzchni próbki, poruszając się w górę i w dół, co powoduje przemieszczenie wspornika.
W jednym z typów AFM wiązka laserowa jest skierowana na wspornik, a gdy się porusza, porusza się również odbicie lasera.
Fotodetektor czuły na położenie rejestruje odchylenie wiązki laserowej.
Dane są przesyłane do komputera, gdzie oprogramowanie może je przetworzyć w celu wygenerowania trójwymiarowego obrazu powierzchni próbki.

<ol>
	<li>Casuso, Ignacio, Felix Rico i Simon Scheuring. "Biologiczne AFM: skąd pochodzimy – gdzie jesteśmy – dokąd możemy się udać". Dziennik Rozpoznawania Molekularnego 24.3 (2011): 406-413.</li>
	<li>Garcıa, Ricardo i Ruben Perez. "Metody dynamicznej mikroskopii sił atomowych". Raporty z badań powierzchniowych 47.6-8 (2002): 197-301.</li>
</ol>

mikroskopia sił atomowych

Atomic Force Microscopy

Mikroskopia sił atomowych (AFM) to rodzaj mikroskopii z sondą skanującą, która umożliwia analizę szczegółów topograficznych różnych próbek, takich jak ceramika, szkło, polimery i próbki biologiczne. AFM oferuje ponad 1000 razy większą rozdzielczość niż optyczny system obrazowania. Obrazy generowane z AFM to trójwymiarowe profile powierzchni, oferujące przewagę nad płaskimi, dwuwymiarowymi obrazami uzyskanymi z innych technik obrazowania. Sonda AFM Sonda jest uważana za serce każdego zestawu AFM i składa się z zespołu wspornika i końcówki. Sondy są najczęściej wymienianą częścią tego typu mikroskopu, ponieważ ciągła interakcja z próbkami powoduje zużycie końcówki. Dlatego wybór materiału na sondę zależy od właściwości próbki. Sondy krzemowe, używane do analizy twardych próbek, są sztywniejsze i ostrzejsze niż sondy z azotku krzemu, które lepiej nadają się do skanowania miękkich próbek. Te ostre końcówki są produkowane przy użyciu trawienia elektrochemicznego lub nanorurek węglowych w celu zapewnienia większej dokładności analizy. Tryby obrazowania AFM W AFM topografię powierzchni bada się za pomocą interakcji pomiędzy końcówką sondy a powierzchnią próbki. Istnieją dwa główne tryby obrazowania — tryb statyczny, nazywany także trybem kontaktowym, oraz tryb dynamiczny. W trybie statycznym lub kontaktowym końcówka sondy ma ciągły kontakt z powierzchnią próbki. Gdy końcówka przesuwa się po powierzchni, siły odpychające pomiędzy próbką a końcówką powodują zgięcie wspornika, które jest rejestrowane. Cała powierzchnia próbki jest skanowana tam i z powrotem zarówno w osi x, jak i y, co nazywa się skanowaniem rastrowym, podczas gdy pionowy ruch wspornika rejestruje oś z, generując w ten sposób obraz 3D. W trybie dynamicznym sonda oscyluje tuż nad powierzchnią próbki, zbliżając się do powierzchni, ale jej nie dotykając. Siły przyciągania i odpychania determinują zmianę odległości pomiędzy końcówką a próbką, wpływając na amplitudę oscylacji wspornika. Informacje te są rejestrowane w celu skonstruowania topografii powierzchni próbki.

Mikroskopia sił atomowych

Mikroskopia sił atomowych (AFM) to rodzaj mikroskopii z sondą skanującą, która może analizować szczegóły topograficzne różnych próbek, takich jak ceramika, szkło, ...

Education

JoVE Core

Cell Biology

Biologia komórki

Unit 1

Jednostka 1

Visualizing Cells, Tissues, and Molecules

Wizualizacja komórek, tkanek i cząsteczek

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

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

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imaging biological samples with optical microscopy

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How Light Microscopes Bring Samples Into View

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Surface-Only Imaging with TIRF Microscopy

Total internal reflection fluorescence microscopy, or TIRF, is a microscope method used to view fluorophores near a solid surface with a higher refractive index, such as a glass coverslip. It is useful when scientists want to study signals close to the cell surface. TIRF works when light from a medium with a lower refractive index, such as air, hits the glass coverslip at a critical angle. Instead of entering the glass, the light undergoes total internal reflection. This reflection creates an...

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...

super-resolution fluorescence microscopy

Sharper Cell Images with Fluorescence Microscopy

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scanning electron microscopy

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transmission electron microscopy

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Electron Microscopy Sample Prep Methods

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immunogold electron microscopy

Immunogold Labeling in Electron Microscopy

Immunogold labeling in electron microscopy uses antibodies and tiny gold particles to find specific proteins in cells and tissues. The gold particles are very electron-dense, which means they show up clearly in electron microscope images. This gives researchers a high-resolution way to see where proteins are located and to compare their amounts under different stimulation conditions. The method can reveal proteins on the cell surface and inside cells. It has been used to study proteins...

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Cryo-EM, or cryo-electron microscopy, lets scientists image biomolecules in their frozen, native state. It avoids the dehydration, fixation, and staining used in conventional electron microscopy, which can distort samples and create artifacts. It also reduces damage from the electron beam by using gentler imaging conditions. This method is useful when other structure tools have limits. X-ray diffraction needs a molecule to form a crystal, and that is not always possible. Even when...

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3D Imaging with Electron Microscopy

Transmission electron microscopy (TEM) can build 3D images of biological samples. It does this with electron microscope tomography and single-particle reconstruction. Tomography can show cell parts or small cells in vivo, while single-particle reconstruction is used for macromolecules and macromolecular complexes in vitro only. Electron tomography can be done in TEM or in STEM, which stands for scanning transmission electron microscopy. STEM is mainly used for thick biological specimens. It...

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 Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Atomic Force Microscopy for Surface Mapping

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