An Iranian researcher from the University of Tehran succeeded in the improvement of contrast in nanoparticles imaging in liquid media which can be used as imaging instruction by applying atomic force microscope in liquid media. The researcher achieved the results based on the proposed relation between the sensitivity of specific cantilevers mode to the toughness and softness of nanoparticles studied by him. By using Euler-Bernoulli method and by taking into account the effects of hydrodynamic function in liquid media, an analytical correlation was presented to calculate cantilever resonance frequency. The results obtained from the correlation were compared to those obtained from experimental data. The study showed that the presented correlation was more precise, specially in low modes, in comparison to the previous correlations. Then, the sensitivity of cantilever specific modes to mechanical properties of nanoparticles, including Young Modules and their toughness and softness, was investigated as all. The instruction for the excitation of cantilever modes was proposed based on the obtained results and material properties to obtain better image contrast. Excitation of higher modes in liquid media results in better image contrast depending on the thoroughness or softness of the material, or in other words, Young Modules of the material. Therefore, more precise information can be obtained from mechanical, physical, and chemical properties of nanoparticles by using excitation of higher modes in tough materials and excitation of first mode in soft materials. The results can be used as an instruction for imaging by using atomic force microscope in liquid media. Results of the research have applications in industries and researches related to imaging and to the investigation of physical, chemical, and mechanical properties of nanoparticles in liquid media, which has direct connection with the field of nanobiotechnology, medical sciences, biology, metallurgy, and polymer sciences. Results of the research have been published in December 2013 in Ultramicroscopy, vol. 135, pp. 84-88.