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Investigation of morphology and mechanical properties of biological specimens using atomic force microscopy (AFM) often requires its operation in liquid environment. Due to the hydrodynamic force, the vibration of AFM cantilevers in liquid shows dramatically different dynamic characteristics from that in air. A good understanding of the dynamics of AFM cantilevers vibrating in liquid is needed for the interpretation of scanning images, selection of AFM operating conditions, and evaluation of sample's mechanical properties. In this study, a finite element (FE) model is used for frequency and transient response analysis of AFM cantilevers in tapping mode (TM) operated in air or liquid. Hydrodynamic force exerted by the fluid on AFM cantilevers is approximated by additional mass and hydrodynamic damping. The additional mass and hydrodynamic damping matrices corresponding to beam elements are derived. With this model, numerical simulations are performed for an AFM cantilever to obtain the frequency and transient responses of the cantilever in air and liquid. The comparison between our simulated results and the experimentally obtained ones shows good agreement. Based on the simulations, different characteristics of cantilever dynamics in air and liquid are discussed.
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http://dx.doi.org/10.1016/j.ultramic.2007.01.022 | DOI Listing |
Colloids Surf B Biointerfaces
December 2025
Department of Medical Physics, Graduate School of Medicine, Tohoku University, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan; International Center for Synchrotron Radiation Innovation Smart (SRIS), Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577, Japan. Electronic address: kohsu
For precision medicine, it is necessary to quantify the expression levels of marker proteins as well as their micro-regional densities. Many techniques are available for evaluating protein expression levels on tissue sections of patients in order to assess the malignancy of cancer and predict drug efficacy. These technologies, however, have not achieved sufficiently accurate clinical outcome predictions.
View Article and Find Full Text PDFSmall
August 2025
Department of Physical Chemistry II, University of Bayreuth, Universitätsstraße 30, 95447, Bayreuth, Germany.
The mechanical characterization of soft particulate materials by nanoindentation based on atomic force microscopy (AFM) is a well-established technique in materials science. However, this technique is very time-consuming for micrometer-sized particles as the indenter has to be centered on the particle apex. As microgels have a broad distribution of Young's moduli, it is important to measure many particles to achieve statistically reliable data.
View Article and Find Full Text PDFBiochem Biophys Res Commun
September 2025
Istituto Officina dei Materiali-Consiglio Nazionale delle Ricerche (IOM-CNR), Basovizza, 34149, Trieste, Italy. Electronic address:
Understanding the gating mechanism of the mechanosensitive ion channel PIEZO2 is crucial because of its involvement in key physiological and pathological processes. The use of a bead-functionalized cantilever by atomic force microscopy (AFM) provides a well-defined contact area, enabling accurate and reproducible force delivery to the cell surface. This approach enables the application of a spatiotemporally controlled mechanical stimulation to single PIEZO2-transfected HEK-293 cell at short (0.
View Article and Find Full Text PDFLangmuir
August 2025
Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907-2100, United States.
The atomic force microscope (AFM) is used to measure the forces between a probe particle mounted at the end of the flexible AFM cantilever and a given substrate or sample. Most existing models that describe the cantilever deflections in AFM experiments assume the sample is perfectly leveled. However, the samples are rarely, if ever, placed exactly perpendicular to the approach direction of the cantilever.
View Article and Find Full Text PDFAdv Sci (Weinh)
August 2025
Department of Materials Design and Innovation, University at Buffalo, The State University of New York, Buffalo, NY, 14260.
In this study, we demonstrate a novel approach for synthesizing free-standing and transferable polycrystalline diamond membranes (PCDm) to overcome these constraints, thus enabling a much wider spectrum of applications. Two types of PCDm cantilevers -Top-Surface-Up (TSU) and Bottom-Surface-Up (BSU) are fabricated, each with two different sets of dimensions: 150 µm (width) × 1200 µm (length) and 300 µm (width) × 2000 µm (length). Their mechanical and electrical properties are systematically investigated.
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