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

原子間力顕微鏡またはAFMは、ナノプローブを使用して画像を生成し、ナノメートルの分解能でサンプルに関するトポグラフィー情報を提供します。
光学顕微鏡は最大1000倍まで拡大できますが、AFMの倍率は最大1,000,000倍です。
AFMは、固定試料と生体試料の両方の画像を作成できるため、アクチンダイナミクスなどの動的な細胞プロセスを捉えることができます。
AFMナノプローブは、柔軟なカンチレバーの端に取り付けられ、一緒にサンプルをスキャンします。プローブはサンプル表面の輪郭をたどり、上下に動き、カンチレバーを変位させます。
AFMの一種では、レーザー光をカンチレバーに向け、その動きに合わせてレーザーの反射も移動します。
位置感応型光検出器は、レーザービームの偏向を記録します。
データはコンピューターに送信され、ソフトウェアがそれを処理してサンプル表面の3次元画像を生成できます。

<ol>
	<li>Casuso, Ignacio, Felix Rico, and Simon Scheuring. "Biological AFM: where we come from-where we are-where we may go." Journal of Molecular Recognition 24.3 (2011): 406-413.</li>
	<li>「動的原子間力顕微鏡法」 表面科学レポート 47.6-8 (2002): 197-301.</li>
</ol>

原子間力顕微鏡

Atomic Force Microscopy

原子間力顕微鏡 (AFM) は走査型プローブ顕微鏡の一種で、セラミック、ガラス、ポリマー、生体サンプルなどのさまざまな試料の形状の詳細を分析できます。 AFM は、光学イメージング 技術よりも 1000 倍以上の解像度です。 AFM から生成される画像は 3 次元の表面プロファイルであり、他のイメージング技術による平面の 2 次元画像に比べて利点があります。

AFM プローブ

プローブは AFM セットアップの中心とみなされ、カンチレバーとチップ アセンブリで構成されます。 サンプルとの絶え間ない相互作用によりチップが磨耗するため、このタイプの顕微鏡ではプローブが最も一般的に交換される部品です。 したがって、プローブの材料の選択はサンプルの特性に依存します。 硬いサンプルの分析に使用されるシリコン プローブは、柔らかいサンプルのスキャンに適した窒化シリコン プローブよりも硬くて鋭いです。 これらの鋭い先端は、より高精度な分析のために電気化学エッチングまたはカーボン ナノチューブを使用して製造されています。

AFMのイメージングモード

AFM では、プローブ先端とサンプル表面の間の相互作用を使用して表面トポグラフィーが研究されます。 主なイメージング モードには、静的モード (コンタクト モードとも呼ばれます) と動的モードの 2 つがあります。

静的モードまたは接触モードでは、プローブの先端はサンプル表面と継続的に接触します。 チップが表面上を引きずられると、サンプルとチップの間の反発力によってカンチレバーの曲がりが記録されます。 試料表面全体は、ラスター スキャンと呼ばれる x 軸と y 軸の両方で前後にスキャンされ、カンチレバーの垂直方向の動きによって z 軸が記録され、3D 画像が生成されます。

ダイナミック モードでは、プローブはサンプル表面のすぐ上で振動し、サンプル表面に近づきますが、接触することはありません。 引力と斥力によってチップとサンプル間の距離の変化が決まり、カンチレバーの振動の振幅に影響を与えます。 このフィードバックは、サンプルの表面トポグラフィーを構築するために記録されます。

原子間力顕微鏡(AFM)は、セラミックス、ガラスなどのさまざまな試料のトポグラフィーの詳細を分析できる走査型プローブ顕微鏡の一種です。

Education

JoVE Core

Cell Biology

細胞生物学

Unit 1

ユニット1

Visualizing Cells, Tissues, and Molecules

細胞・組織・分子の可視化

KEY TERMS AND CONCEPTS

主要用語と概念

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

imaging biological samples with optical microscopy

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Optical microscopy uses light and lenses to make tiny biological samples visible. Antonie van Leeuwenhoek built the first compound optical microscope in the 17th century to view blood cells, bacteria, and yeast cells. In 1830, Joseph Jackson Lister developed an essentially modern light microscope. During the 20th century, microscopes gained better magnification and resolution. A sample is placed on a glass slide and clipped onto the stage, which is the flat platform of the microscope. The...

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Surface-Only Imaging with TIRF Microscopy

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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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Sharper Cell Images with Fluorescence Microscopy

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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 細胞生物学は、複雑な細胞プロセスを、わかりやすく包括的なアニメーション ビデオ レッスンで説明します。このコレクションは、細胞小器官や膜、細胞輸送、細胞のエネルギー学など、細胞の必須コンポーネントと機能に焦点を当てています。これは、実際の研究実験における細胞生物学の応用を実証する科学者による実際のビデオによって補足されています。

Atomic Force Microscopy for Surface Mapping

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