Atomic force microscope (AFM) is one of the powerful and useful tools in nanoscale science and technologies with applications from surface characterization in material science, to the study of living biological system in their natural environment. AFM operate in three mods of contact, non-contact and tapping mode. In this paper, by focusing on the development of a more comprehensive model of an AFM micro-cantilever beam, considering the effects of mass and rotary inertia of the tip using Euler-Bernoulli beam theory is considered. The comparison of the present results and the results of other investigators, which has been done in case studies, generally shows a very good agreement. The results show that the effect of mass and rotary inertia of the tip depending on its dimensions is important and should be considered. Finally, the effects of cantilever inclination and tip height on the resonance frequencies are also examind.

In this paper, the dynamic behavior of atomic force microscope (AFM) based on non-classical strain gradient theory was analyzed. For this aim atomic force microscope micro-beam with attached tip has been modeled as a lumped mass. Micro-beam, stimulated via a piezoelectric element attached to the end of clamped and non-linear partial differential equation of the system has been extracted based on Euler-Bernoulli theory and converted into ordinary differential equation by using Galerkin and separation method. The classic continuum theory, because not taking size effect into consideration, has little accuracy in predicting the mechanical behavior of Nano devices. In this study, the stability region of micro-beam is determined analytically and validated by comparison with numerical results. Difference between presented analysis in dynamic behavior of micro-beam by classic and non-classic theories has been shown with a variety of diagrams. It is clear that considering the size effect changes the dynamical behavior of the problem completely and it is possible, and while classical theory predicts stable behavior for microscope the size effect is caused bi-stability. The results in this paper are very useful for the design and analysis of atomic force microscope.

In this paper, the free vibration behaviors and flexural sensitivity of atomic force microscope cantilevers with small-scale effects are investigated. To study the small-scale effects on natural frequencies and flexural sensitivity, the consistent couple stress theory is applied. In this theory, the couple stress is assumed skew-symmetric. Unlike the classical beam theory, the new model contains a material-length-scale parameter and can capture the size effect. For this purpose, the Euler– Bernoulli beam theory is used to develop the AFM cantilever. The tip interacts with the sample that is modeled by a spring with constant of. The equation of motion is obtained through a variational formulation based on Hamilton’ s principle. In addition, the analytical expressions for the natural frequency and sensitivity are also derived. At the end, some numerical results are selected to study the effects of material-length-scale parameter and dimensionless thickness on the natural frequency and flexural sensitivity.

Deformation of cells and changing in mechanical specifications is one of the most important of cancer as serious illness. In fact, variation of mechanical properties of the cells is one of the important effects of the cancer. Here, the mechanical specifications of normal and cancerous skin cells have been studied. HU02, A-375 and A-431 as the normal and cancerous skin cells respectively have been investigated. The mechanical specifications including elasticity modulus and adhesion have been obtained using nanoindentation using JPK Instruments-Nano Wizard 3 atomic force microscope (AFM). The JPK SPM Data Processing software (v.5.0.96) was used to obtain the mechanical specifications. The results show that cancer can decrease the elasticity modulus of the cells to half in skin and increases the adhesion up to 38 times rather than normal cells. The cancerous cells are more adhesive than normal cells. The height of the cancerous cell is greater than normal cell.

In general, every normal cell of the human body, which consists of different parts such as the nucleus, cell membrane and protein nanofibers, has a certain mechanical hardness and strength. Any noticeable change in this strength indicates a disease. One way to diagnose various diseases such as cancer in normal cells of the human body is to measure the amount of changes that have occurred in their mechanical properties. In the present paper, mechanical properties including modulus of elasticity and adhesion force of Ago-1522 cell, which is considered as a natural skin cell, using JPK atomic force microscope (made in Germany), Nano Wizard 3 in both extension and retraction modes, and obtained at a temperature of 37 degrees Celsius. Based on the results, the average elastic modulus for the cell in the extension mode (as the valid mode in the reports) is equal to 574.4 Pa. The adhesion force is equivalent to N in retraction mode. Based on images taken from the surface of the cell with an atomic force microscope, its maximum height is 0.4 micrometers.

In this paper, an atomic force microscope is modeled based on non-classical nonlocal theory and nonlinear vibration of the system is analyzed and controlled. In this modeling, the Hamilton principle is used to derive the governing equation of Euler-Bernoulli nanocantilever based on the Eringen nonlocal elasticity theory considering Von-Karman geometric non-linearity. In the next step, using the Galerkin method, the governing dynamics differential equation of the atomic force microscope is obtained in the presence of attractive and repulsive van der Waals forces. The governing nonlinear equation is solved by employing multiple time scales method, and primary and secondary resonance of the atomic force microscope is studied. In this regard, the frequency response and excitation amplitude curves of primary, superharmonic and subharmonic resonances are plotted for different values of the nonlocal parameter. Accordingly, it is shown that primary, superharmonic and subharmonic resonances of atomic force microscope are significantly affected by the nonlocal parameter. The results show that the use of nonlocal theory is a fundamental necessity for analyzing nonlinear vibrations of the atomic force microscope. Then, in addition to dynamic analysis, the chaotic vibrations are completely controlled and removed in the nonlocal model of the atomic force microscope by designing and implementing the robust adaptive fuzzy controller. For this task, the robust adaptive fuzzy controller which is considered as a powerful method of chaos controlling is used in the nonlocal model of atomic force microscope. The obtained results are used in the design and control process of the atomic force microscope.

In the present investigation, the mechanical properties of mesenchymal stem cells (MSC) and carcinomatous cells of bone tissue (MG-63 and SAOS-2) has been studied applying AFM. Based on the sufficient similarity of mechanical characterizations of normal human osteoblast cells (NHOst) with mesenchymal stem cells (MSC), MSC have been applied instead to NHOst. Due to the outcomes, the elastic modules of MG-63 and SAOS-2 are lower than MSC. The elastic modulus of MG-63 and SOAS-2 cells were estimated before and after chemo and plasma treatment. MTT appraisal has been applied to define the convenient dosages for 24- and 48-h incubations due to the IC50 cell viability concentration. The elastic modules of MG-63 (917 Pa) and SAOS-2 (697 Pa) cell increase to 1.72 (1579 Pa) and 5.44 (4985 Pa) (after 24, 48 h) times compared to untreated MG-63 cell and 1.15 (802 Pa) and 7.49 (5225 Pa) (24, 48 h) times compared to untreated SAOS-2 cell. The plasma treatment increased the elastic modules of MG-63 and SAOS-2 cells. In the second section, the resonant frequencies and enlargement of the frequency response function of the AFM beam’s motions have been analyzed using FEM and experimental procedures by AFM. The outcomes displayed that raising the specimens’ hardness raises the resonant frequency. Lastly, the FEM and experimental outcomes have been evaluated and displayed the good agreement.