Experimental extraction of modulus of elasticity of gastric cancer tissue using cylindrical developed contact mechanics models

The physical and chemical properties of living tissues change with the change in their physiological conditions during disease. AFM can perform surface imaging and ultrastructural observation of living tissues at nanometer resolution under near-physiological conditions and collect force spectroscopic information, which enables the study of tissue mechanical properties. In this research, AFM was used to measure the elasticity modulus of stomach cancer tissue. For this purpose, in order to bring the theoretical results closer to the experimental reality, three-dimensional modeling of the developed contact theories has been done. Since in most of the past research, the shape of spherical target particles has been assumed, as an important innovation, in this research, cylindrical contact models including Hertz, Dawson, Nikpour, Hoeprich, and Lundberg have been modeled, and the simulation of each of these models has been done using MATLAB software. The simulation results of contact models have been compared with the results of experimental work. From the results obtained from this comparison, the modulus of elasticity in kilopascals at the most appropriate penetration depth of the AFM needle for biological tissue has been extracted. The results have shown that the Hoeprich model is a suitable model for theoretical simulation and is closest to the experimental results. By comparing the obtained results and the previous results, the difference percentage of the results for gastric cancer tissue is between 3 and 20% at the end, and the validity of the results was checked.