この研究は、生物環境研究局、米国エネルギー省のとバージニア州の連邦保健研究委員会からの助成金によって後援される。オークリッジ国立研究所は、契約番号DE - AC05 - 00OR22725下で米国エネルギー省のためにUT - Battelle氏、LLCによって管理されます。

1。マイカの準備： <ol><li> AFM顕微鏡（約22 × 30 mm）を合わせて必要なサイズにハサミでマイカを（電子顕微鏡の科学）カット。 </li><li>唯一の滑らかな連続した層が残るまで、外側の層を除去するためにテープを使用して、一般的に開裂し、両側のマイカ、。 </li></ol> 2。ゼラチン溶液の調製： <ol><li>実験室の瓶に100mlの蒸留水を追加。 </li><li>水が沸騰し始めるまで電子レンジでボトルを加熱する。 （電子レンジが使用できない場合は、水をホットプレート上でビーカーで加熱することができます。） </li><li>ゼラチン0.5グラム（シグマG - 6144、G - 2625またはG - 2500）を秤量し、熱い蒸留水に加える。 </li><li>ゆっくりとゼラチンになるまで渦巻き瓶が完全に溶解されています。 </li><li> 60から70℃にゼラチン溶液を冷却</li><li>カット切断されたマイカを浸漬することが可能な小型のビーカー（20ml）に約15 mLを注ぐ。 </li></ol> 3。マイカ塗装： <ol><li>温めたゼラチン溶液に浸すマイカの正方形をしてマイカが（図1a）コーティングであることがすぐにそのような撤回。 </li><li>コー​​ティング後は、（図1b）周囲の空気中で乾燥するためにペーパータオルで、エッジで、すぐにマイカをサポートしています。ゼラチン被覆マイカは、少なくとも2週間に使用することができます。過剰ゼラチン溶液は冷蔵保管し、単純に60から70℃の間にストック溶液を加熱によって約ヶ月間使用できます。ケアは、ゼラチンが再加熱時に沸騰されないように注意する必要があります。 </li></ol> 4。ゼラチンコートされたマイカの取り付け細菌： <ol><li> 800〜4500 rcfで - 細菌培養物のペレットを1 mLの（600nmで1.0 OD 0.5）。細菌によっては、最小のRCFを使用しているペレットは〜5分で細胞なります。 </li><li>フィルタ処理された脱イオン水または緩衝液の同量でペレットを洗浄します。 </li><li>遠心分離によって再び細胞を回収。 </li><li> nanopure脱イオン水または緩衝液の500μLで速やかにペレットを再懸濁する。 （細菌懸濁液が目に見えてAFMイメージングのための細胞の適切な濃度を得るために濁ってしてください。） </li><li>ピペットチップ（図1c）を使用して表面にゼラチン被覆マイカと拡散して細胞懸濁液（10〜20μL）を適用します。ケアは、菌液を適用したり、拡散しながら物理的にピペットの先端をゼラチン表面に触れないように注意してください。 </li><li>表面は10分間休ませ、水または緩衝液（図1 CD）のストリームでリンスすることができます。手順では、サンプルが乾燥して許可されていないことを保証するように注意してください。 </li></ol> 5。代表的な結果： 図2は、ゼラチン被覆マイカ上でマウントされており、AFMによって画像化された細菌細胞の例の画像を示す。我々の研究室では、サンプルは一般的に100μmの走査ヘッドを装備したPicoPlus原子間力顕微鏡を（アジレントテクノロジー、寺院、アリゾナ州）を用いて撮像される。楽器は、0.5から1.0行/秒の走査速度でラインスキャン当たり128から512ピクセルで運営されています一般的に使用されるカンチレバーは、0.01〜0.1 NN / nmの範囲の公称ばね定数とVeeco社の窒化シリコンプローブ（MLCT - AUHW、Veeco社、サンタバーバラ、カリフォルニア州）です。 <img src="/files/ftp_upload/2880/2880fig1.jpg" alt="図1"/> 図1。60〜70 ° C、20 mlのビーカーに入れているの温度でゼラチン。ピンセットを使用すると、新鮮な劈開マイカの正方形は、完全にマイクロ遠心ラック（B）にもたれてペーパータオルの上に直立撤回し、配置された（）ゼラチン中に浸漬されています。細菌サンプルの液滴は、XとY方向（c）の両方のピペットチップマイカと拡散に配置されます。サンプルは、少なくとも10分間雲母表面にインキュベートさせた後、蒸留水の流れでサンプルをすすいでください。固定化がうまくいったら（d）の右パネルに示すように雲母に不透明な点を見ることができます。固定化が成功しなかった場合には、左側のパネルのように雲母の明確な部分を取得します。ゼラチン扱わマイカ上に置かれた液滴の細菌の濃度にマイカスケール上の不透明なスポット。 <img src="/files/ftp_upload/2880/2880fig2.jpg" alt="図2"/> E.の図2。AFM像大腸菌 。パネル（）で、細胞をゼラチンコートしたマイカ上にマウントされ、0.005 M PBSで画像化。比較のために、ゼラチンコートされたマイカ上に実装し、空中で結像される細菌細胞の画像は、パネル（b）に示されています。セプタムは、液体中に収集された画像ではっきりと表示されますが、のような毛の存在（挿入図（b））で示される以上の解像度は、、空気中で得ることができます。

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利害の衝突は宣言されません。

様々な要因がAFMによる微生物取付けセルおよびイメージングに影響を与える可能性があります。コー​​ティングのために使用されるゼラチンは、雲母が重要です。商業用ゼラチンは、魚、牛、そして豚を含む脊椎動物の数から絶縁されています。起源と処理方法はどちらも細菌の固定化のためのゼラチンの適合性を決定する。多数の情報源とゼラチンのタイプは固定細菌で、その有効性を?...

<table border="1"><tbody><tr><td> の名前 </td><td> 会社 </td><td> カタログ番号 </td></tr><tr><td>ゼラチン</td><td>シグマ、セントルイス、MO </td><td> G6144、G2625やG2500 </td></tr><tr><td> PicoPlus原子間力顕微鏡</td><td>アジレントテクノロジー、テンペ、アリゾナ州</td><td></td></tr><tr><td> AFMのカンチレバー</td><td> Veeco社、サンタバーバラ、カリフォルニア州</td><td> MLCT - AUHW </td></tr></tbody></table>

bacterial immobilization for imaging by atomic force microscopy

AFMは、イメージングツールを機械的プローブ表面の高分解能（ナノスケール）です。それは化学的にサンプルを治療することなく、液体環境では、画像セルと生体分子への能力を持っています。この目標を達成するために、サンプルが十分にスキャンAFMのカンチレバーの先端によって加えられる力によって除去を防ぐために、取り付け面に付着する必要があります。多くの例では、成功した画像は、取付面へのサンプルの固定化に依存します。最適に、固定化は、代謝プロセスと機能的な属性が損なわれないように、サンプルへの低侵襲である必要があります。ブタ（豚）、ゼラチンでコーティングしたばかりの劈開マイカの表面によって、負に帯電した細菌が表面に固定化することができるとAFMによる液中に撮像。ゼラチン被覆マイカ上の細菌の細胞の固定化は、負に帯電した細菌と正に帯電したゼラチンの間の静電相互作用に起因する可能性が最も高いです。いくつかの要因は、細菌が中断されている液体の化学成分、ゼラチンコートされたマイカ上の細菌の培養時間、菌株や菌がイメージングされる媒体の表面特性を含む細菌の固定化、妨げになることがあります。全体的に、ゼラチンコートされたマイカの使用は、イメージングの微生物細胞のための一般的に適用可能であることが判明した。

Watch this Scientific Journal Video about Bacterial Immobilization for Imaging by Atomic Force Microscopy at JoVE.com

Bacterial Immobilization for Imaging by Atomic Force Microscopy

住んでいるグラム陰性およびグラム陽性細菌は、ゼラチンコートしたマイカ上に固定し、原子間力顕微鏡（AFM）を用いて液体中に撮像することができます。

原子間力顕微鏡によるイメージングのための細菌の固定化

AFM is a high-resolution (nm scale) imaging tool that mechanically probes a surface.  It has the ability to image cells and biomolecules, in a liquid ...

bacterial-immobilization-for-imaging-by-atomic-force-microscopy

Research

JoVE Journal

Bioengineering

17.2K ビュー.  Oak Ridge National Laboratory. 住んでいるグラム陰性およびグラム陽性細菌は、ゼラチンコートしたマイカ上に固定し、原子間力顕微鏡（AFM）を用いて液体中に撮像することができます。

ビデオ: Bacterial Immobilization for Imaging by Atomic Force Microscopy

Three-dimensional Optical-resolution Photoacoustic Microscopy

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. 
The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM)1, where the optical irradiation is focused to the diffraction limit to achieve cellular1 or even subcellular2 level lateral resolution. As a valuable complement to existing optical microscopy technologies, OR-PAM brings in at least two novelties. First and most importantly, OR-PAM detects optical absorption contrasts with extraordinary sensitivity (i.e., 100%). Combining OR-PAM with fluorescence microscopy3 or with optical-scattering-based OCT4 (or with both) provides comprehensive optical properties of biological tissues. Second, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences (i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra. 
Unique for optical absorption imaging, OR-PAM has demonstrated broad biomedical applications since its invention, including, but not limited to, neurology5, 6, ophthalmology7, 8, vascular biology9, and dermatology10. In this video, we teach the system configuration and alignment of OR-PAM as well as the experimental procedures for in vivo functional microvascular imaging.

Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.

三次元光学分解能光音響顕微鏡

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As ...

生物工学

Visualization of Recombinant DNA and Protein Complexes Using Atomic Force Microscopy

Atomic force microscopy (AFM) allows for the visualizing of individual proteins, DNA molecules, protein-protein complexes, and DNA-protein complexes. On the end of the microscope's cantilever is a nano-scale probe, which traverses image areas ranging from nanometers to micrometers, measuring the elevation of macromolecules resting on the substrate surface at any given point. Electrostatic forces cause proteins, lipids, and nucleic acids to loosely attach to the substrate in random orientations and permit imaging. The generated data resemble a topographical map, where the macromolecules resolve as three-dimensional particles of discrete sizes (Figure 1) 1,2. Tapping mode AFM involves the repeated oscillation of the cantilever, which permits imaging of relatively soft biomaterials such as DNA and proteins. One of the notable benefits of AFM over other nanoscale microscopy techniques is its relative adaptability to visualize individual proteins and macromolecular complexes in aqueous buffers, including near-physiologic buffered conditions, in real-time, and without staining or coating the sample to be imaged. 
The method presented here describes the imaging of DNA and an immunoadsorbed transcription factor (i.e. the glucocorticoid receptor, GR) in buffered solution (Figure 2). Immunoadsorbed proteins and protein complexes can be separated from the immunoadsorbing antibody-bead pellet by competition with the antibody epitope and then imaged (Figure 2A). This allows for biochemical manipulation of the biomolecules of interest prior to imaging. Once purified, DNA and proteins can be mixed and the resultant interacting complex can be imaged as well. Binding of DNA to mica requires a divalent cation 3,such as Ni2+ or Mg2+, which can be added to sample buffers yet maintain protein activity. Using a similar approach, AFM has been utilized to visualize individual enzymes, including RNA polymerase 4 and a repair enzyme 5, bound to individual DNA strands. These experiments provide significant insight into the protein-protein and DNA-protein biophysical interactions taking place at the molecular level. Imaging individual macromolecular particles with AFM can be useful for determining particle homogeneity and for identifying the physical arrangement of constituent components of the imaged particles. While the present method was developed for visualization of GR-chaperone protein complexes 1,2 and DNA strands to which the GR can bind, it can be applied broadly to imaging DNA and protein samples from a variety of sources.

A tapping mode atomic force microscope (AFM) method for the visualization of plasmid DNA, cytoplasmic proteins, and DNA-protein complexes is described. The method includes alternate approaches for preparing samples for AFM imaging following biochemical manipulation. DNA containing specific protein interacting regions are observed in near-physiologic buffer conditions.

原子間力顕微鏡を用いて組換えDNAとタンパク質の複合体の可視化

Atomic force microscopy (AFM) allows for the visualizing of individual proteins, DNA molecules, protein-protein complexes, and DNA-protein complexes. On ...

Quantifying the Mechanical Properties of the Endothelial Glycocalyx with Atomic Force Microscopy

Our understanding of the interaction of leukocytes and the vessel wall during leukocyte capture is limited by an incomplete understanding of the mechanical properties of the endothelial surface layer. It is known that adhesion molecules on leukocytes are distributed non-uniformly relative to surface topography 3, that topography limits adhesive bond formation with other surfaces 9, and that physiological contact forces (&asymp; 5.0 &minus; 10.0 pN per microvillus) can compress the microvilli to as little as a third of their resting length, increasing the accessibility of molecules to the opposing surface 3, 7. We consider the endothelium as a two-layered structure, the relatively rigid cell body, plus the glycocalyx, a soft protective sugar coating on the luminal surface 6. It has been shown that the glycocalyx can act as a barrier to reduce adhesion of leukocytes to the endothelial surface 4. In this report we begin to address the deformability of endothelial surfaces to understand how the endothelial mechanical stiffness might affect bond formation. Endothelial cells grown in static culture do not express a robust glycocalyx, but cells grown under physiological flow conditions begin to approximate the glycocalyx observed in vivo 2. The modulus of the endothelial cell body has been measured using atomic force microscopy (AFM) to be approximately 5 to 20 kPa 5. The thickness and structure of the glycocalyx have been studied using electron microscopy 8, and the modulus of the glycocalyx has been approximated using indirect methods, but to our knowledge, there have been no published reports of a direct measurement of the glycocalyx modulus in living cells. In this study, we present indentation experiments made with a novel AFM probe on cells that have been cultured in conditions to maximize their glycocalyx expression to make direct measurements of the modulus and thickness of the endothelial glycocalyx.

The mechanical characteristics of endothelial glycocalyx were measured by indentation using micron sized spheres on AFM cantilevers. Endothelial cells were cultured in a custom chamber under physiological flow conditions to induce glycocalyx expression. Data were analyzed using a thin film model to determine the glycocalyx thickness and modulus.

原子間力顕微鏡と内皮グリコカリックスの機械的性質の定量化

Our  understanding of the interaction of leukocytes and the vessel wall during  leukocyte capture is limited by an incomplete understanding of the ...

Measuring the Mechanical Properties of Living Cells Using Atomic Force Microscopy

Mechanical properties of cells and extracellular matrix (ECM) play important roles in many biological processes including stem cell differentiation, tumor formation, and wound healing. Changes in stiffness of cells and ECM are often signs of changes in cell physiology or diseases in tissues. Hence, cell stiffness is an index to evaluate the status of cell cultures. Among the multitude of methods applied to measure the stiffness of cells and tissues, micro-indentation using an Atomic Force Microscope (AFM) provides a way to reliably measure the stiffness of living cells. This method has been widely applied to characterize the micro-scale stiffness for a variety of materials ranging from metal surfaces to soft biological tissues and cells. The basic principle of this method is to indent a cell with an AFM tip of selected geometry and measure the applied force from the bending of the AFM cantilever. Fitting the force-indentation curve to the Hertz model for the corresponding tip geometry can give quantitative measurements of material stiffness. This paper demonstrates the procedure to characterize the stiffness of living cells using AFM. Key steps including the process of AFM calibration, force-curve acquisition, and data analysis using a MATLAB routine are demonstrated. Limitations of this method are also discussed.

This paper demonstrates a protocol to characterize the mechanical properties of living cells by means of microindentation using an Atomic Force Microscope (AFM).

原子間力顕微鏡を用いた生細胞の機械的特性を測定する

Mechanical  properties of cells and extracellular matrix (ECM) play important roles in many  biological processes including stem cell differentiation, ...

High-resolution Spatiotemporal Analysis of Receptor Dynamics by Single-molecule Fluorescence Microscopy

Single-molecule microscopy is emerging as a powerful approach to analyze the behavior of signaling molecules, in particular concerning those aspect (e.g., kinetics, coexistence of different states and populations, transient interactions), which are typically hidden in ensemble measurements, such as those obtained with standard biochemical or microscopy methods. Thus, dynamic events, such as receptor-receptor interactions, can be followed in real time in a living cell with high spatiotemporal resolution. This protocol describes a method based on labeling with small and bright organic fluorophores and total internal reflection fluorescence (TIRF) microscopy to directly visualize single receptors on the surface of living cells. This approach allows one to precisely localize receptors, measure the size of receptor complexes, and capture dynamic events such as transient receptor-receptor interactions. The protocol provides a detailed description of how to perform a single-molecule experiment, including sample preparation, image acquisition and image analysis. As an example, the application of this method to analyze two G-protein-coupled receptors, i.e., &#946;2-adrenergic and &#947;-aminobutyric acid type B (GABAB) receptor, is reported. The protocol can be adapted to other membrane proteins and different cell models, transfection methods and labeling strategies.

This protocol describes how to use total internal reflection fluorescence microscopy to visualize and track single receptors on the surface of living cells and thereby analyze receptor lateral mobility, size of receptor complexes as well as to visualize transient receptor-receptor interactions. This protocol can be extended to other membrane proteins.

単一分子蛍光顕微鏡による受容体ダイナミクスの高分解能時空間解析

Single-molecule microscopy is emerging as a powerful approach to analyze the behavior of signaling molecules, in particular concerning those aspect (e.g., ...

Novel Atomic Force Microscopy Based Biopanning for Isolation of Morphology Specific Reagents against TDP-43 Variants in Amyotrophic Lateral Sclerosis

Because protein variants play critical roles in many diseases including TDP-43 in Amyotrophic Lateral Sclerosis (ALS), alpha-synuclein in Parkinson&#8217;s disease and beta-amyloid and tau in Alzheimer&#8217;s disease, it is critically important to develop morphology specific reagents that can selectively target these disease-specific protein variants to study the role of these variants in disease pathology and for potential diagnostic and therapeutic applications. We have developed novel atomic force microscopy (AFM) based biopanning techniques that enable isolation of reagents that selectively recognize disease-specific protein variants. There are two key phases involved in the process, the negative and positive panning phases. During the negative panning phase, phages that are reactive to off-target antigens are eliminated through multiple rounds of subtractive panning utilizing a series of carefully selected off-target antigens. A key feature in the negative panning phase is utilizing AFM imaging to monitor the process and confirm that all undesired phage particles are removed. For the positive panning phase, the target antigen of interest is fixed on a mica surface and bound phages are eluted and screened to identify phages that selectively bind the target antigen. The target protein variant does not need to be purified providing the appropriate negative panning controls have been used. Even target protein variants that are only present at very low concentrations in complex biological material can be utilized in the positive panning step. Through application of this technology, we acquired antibodies to protein variants of TDP-43 that are selectively found in human ALS brain tissue. We expect that this protocol should be applicable to generating reagents that selectively bind protein variants present in a wide variety of different biological processes and diseases.

Using atomic force microscopy in combination with biopanning technology we created a negative and positive biopanning system to acquire antibodies against disease-specific protein variants present in any biological material, even at low concentrations. We were successful in obtaining antibodies to TDP-43 protein variants involved in Amyotrophic Lateral Sclerosis.

筋萎縮性側索硬化症におけるTDP-43の変異体に対する形態学的試薬の分離のための新規原子間力顕微鏡ベースのバイオパニング

Because protein variants play critical roles in many diseases including TDP-43 in Amyotrophic Lateral Sclerosis (ALS), alpha-synuclein in ...

Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers

Atomic force microscopy (AFM) is a versatile, high-resolution imaging technique that allows visualization of biological membranes. It has sufficient magnification to examine membrane substructures and even individual molecules. AFM can act as a force probe to measure interactions and mechanical properties of membranes. Supported lipid bilayers are conventionally used as membrane models in AFM studies. In this protocol, we demonstrate how to prepare supported bilayers and characterize their structure and mechanical properties using AFM. These include bilayer thickness and breakthrough force. 
The information provided by AFM imaging and force spectroscopy help define mechanical and chemical properties of membranes. These properties play an important role in cellular processes such as maintaining cell hemostasis from environmental stress, bringing membrane proteins together, and stabilizing protein complexes.

We describe a protocol for preparation of supported lipid bilayers and its characterization using atomic force microscopy and force spectroscopy.

原子間力顕微鏡イメージングおよびサポートされている脂質二重層のフォーススペクトロスコピー

Atomic force microscopy (AFM) is a versatile, high-resolution imaging technique that allows visualization of biological membranes. It has sufficient ...

Visualizing Angiogenesis by Multiphoton Microscopy In Vivo in Genetically Modified 3D-PLGA/nHAp Scaffold for Calvarial Critical Bone Defect Repair

The reconstruction of critically sized bone defects remains a serious clinical problem because of poor angiogenesis within tissue-engineered scaffolds during repair, which gives rise to a lack of sufficient blood supply and causes necrosis of the new tissues. Rapid vascularization is a vital prerequisite for new tissue survival and integration with existing host tissue. The de novo generation of vasculature in scaffolds is one of the most important steps in making bone regeneration more efficient, allowing repairing tissue to grow into a scaffold. To tackle this problem, the genetic modification of a biomaterial scaffold is used to accelerate angiogenesis and osteogenesis. However, visualizing and tracking in vivo blood vessel formation in real-time and in three-dimensional (3D) scaffolds or new bone tissue is still an obstacle for bone tissue engineering. Multiphoton microscopy (MPM) is a novel bio-imaging modality that can acquire volumetric data from biological structures in a high-resolution and minimally-invasive manner. The objective of this study was to visualize angiogenesis with multiphoton microscopy in vivo in a genetically modified 3D-PLGA/nHAp scaffold for calvarial critical bone defect repair. PLGA/nHAp scaffolds were functionalized for the sustained delivery of a growth factor pdgf-b gene carrying lentiviral vectors (LV-pdgfb) in order to facilitate angiogenesis and to enhance bone regeneration. In a scaffold-implanted calvarial critical bone defect mouse model, the blood vessel areas (BVAs) in PHp scaffolds were significantly higher than in PH scaffolds. Additionally, the expression of pdgf-b and angiogenesis-related genes, vWF and VEGFR2, increased correspondingly. MicroCT analysis indicated that the new bone formation in the PHp group dramatically improved compared to the other groups. To our knowledge, this is the first time multiphoton microscopy was used in bone tissue-engineering to investigate angiogenesis in a 3D bio-degradable scaffold in vivo and in real-time.

Visualizing Angiogenesis by Multiphoton Microscopy In Vivo in Genetically Modified 3D-PLGA/nHAp Scaffold for Calvarial Critical Bone Defect Repair

Here, we present a protocol to visualize blood vessel formation in vivo and in real-time in 3D scaffolds by multiphoton microscopy. Angiogenesis in genetically modified scaffolds was studied in a murine calvarial critical bone defect model. More new blood vessels were detected in the treatment group than in controls.

頭蓋骨の重要な骨欠損修復の多光子顕微鏡In Vivo遺伝子組み換え 3 D-PLGA/nHAp 足場による血管新生を可視化

The reconstruction of critically sized bone defects remains a serious clinical problem because of poor angiogenesis within tissue-engineered scaffolds ...

Visualizing Adhesion Formation in Cells by Means of Advanced Spinning Disk-Total Internal Reflection Fluorescence Microscopy

In living cells, processes such as adhesion formation involve extensive structural changes in the plasma membrane and the cell interior. In order to visualize these highly dynamic events, two complementary light microscopy techniques that allow fast imaging of live samples were combined: spinning disk microscopy (SD) for fast and high-resolution volume recording and total internal reflection fluorescence (TIRF) microscopy for precise localization and visualization of the plasma membrane. A comprehensive and complete imaging protocol will be shown for guiding through sample preparation, microscope calibration, image formation and acquisition, resulting in multi-color SD-TIRF live imaging series with high spatio-temporal resolution. All necessary image post-processing steps to generate multi-dimensional live imaging datasets, i.e. registration and combination of the individual channels, are provided in a self-written macro for the open source software ImageJ. The imaging of fluorescent proteins during initiation and maturation of adhesion complexes, as well as the formation of the actin cytoskeletal network, was used as a proof of principle for this novel approach. The combination of high resolution 3D microscopy and TIRF provided a detailed description of these complex processes within the cellular environment and, at the same time, precise localization of the membrane-associated molecules detected with a high signal-to-background ratio.

An advanced microscope that permit fast and high-resolution imaging of both, the isolated plasma membrane and the surrounding intracellular volume, will be presented. The integration of spinning disk and total internal reflection fluorescence microscopy in one setup allows live imaging experiments at high acquisition rates up to 3.5 s per image stack.

回転ディスク全内部反射蛍光顕微鏡による細胞の接着の形成の可視化詳細

In living cells, processes such as adhesion formation involve extensive structural changes in the plasma membrane and the cell interior. In order to ...

Application of Atomic Force Microscopy to Detect Early Osteoarthritis

Biomechanical properties of cells and tissues not only regulate their shape and function but are also crucial for maintaining their vitality. Changes in elasticity can propagate or trigger the onset of major diseases like cancer or osteoarthritis (OA). Atomic force microscopy (AFM) has emerged as a strong tool to qualitatively and quantitatively characterize the biomechanical properties of specific biological target structures on a microscopic scale, measuring forces in a range from as small as the piconewton to the micronewton. Biomechanical properties are of special importance in musculoskeletal tissues, which are subjected to high levels of strain. OA as a degenerative disease of the cartilage results in the disruption of the pericellular matrix (PCM) and the spatial rearrangement of the chondrocytes embedded in their extracellular matrix (ECM). Disruption in PCM and ECM has been associated with changes in the biomechanical properties of cartilage. In the present study we used AFM to quantify these changes in relation to the specific spatial pattern changes of the chondrocytes. With each pattern change, significant changes in elasticity were observed for both the PCM and ECM. Measuring the local elasticity thus allows for drawing direct conclusions about the degree of local tissue degeneration in OA.

We present a method to investigate early osteoarthritic changes at the cellular level in articular cartilage by using atomic force microscopy (AFM).

早期変形性関節症の検出に対する原子間力顕微鏡の応用

Biomechanical properties of cells and tissues not only regulate their shape and function but are also crucial for maintaining their vitality. Changes in ...