Micronucleus test of human oral cavity buccal epithelium: Problems, achievement, perspectives

AFM methods for studying the morphology and micromechanical properties of the membrane of human buccal epithelium cell

Using AFM methods in air under normal conditions in a wide range of local force effects ([Formula: see text]< 40 μN) the relief, functional micromechanical properties (elasticity coefficient [Formula: see text], Young's modulus [Formula: see text], elastic [Formula: see text] and plastic [Formula: see text] deformations) and adhesive properties (work [Formula: see text] of adhesive forces [Formula: see text]) of the membranes of living adult cells of human buccal epithelium were studied in the presence of a protective layer < 100 nm of buffer solution that prevented the cells from drying. Almost all geometric and functional characteristics of the membrane in the local approximation at the micro- and nanolevels are affected by size effects and obey the laws of fractal geometry. The Brownian multifractal relief of the membrane is characterized by dimension [Formula: see text] < 2.56 and irregularities < 500 nm vertically and < 2 μm horizontally. Its response to elastic (≤ 6 nN), active (6-21 nN), or passive (> 21 nN) stimulation ([Formula: see text]) is a non-trivial selective process and exhibits a correspondingly elastic ([Formula: see text] 67.4 N/m), active ([Formula: see text] 80.2 N/m) and passive ([Formula: see text] 84.5 N/m) responses. [Formula: see text] and [Formula: see text] depend on [Formula: see text]. Having undergone slight plastic deformations [Formula: see text] < 300 nm, the membrane is capable of restoring its shape. We mapped ([Formula: see text], [Formula: see text] = 2.56; [Formula: see text], [Formula: see text] = 2.68; [Formula: see text], [Formula: see text] = 2.42, [Formula: see text] and [Formula: see text]) indicating its complex cavernous structure.

Study of tribological properties of human buccal epithelium cell membranes using probe microscopy

In this work demostrates a unique method for determining the absolute value of the friction force of a nanoobject on the surface of a cell membrane using atomic force microscopy. The tribological properties of membranes of adult human buccal epithelium cells in the presence of a protective adsorption buffer layer of ~ 100 nm on their surface were studied using atomic force microscopy in the contact scanning mode. Local mapping of the tribological characteristics of the surface was carried out, viz. friction F_L = F_L(x, y) and adhesion F_adh = F_adh(x, y) forces were measured. Studies of the friction force F_fr on the membrane surface at the nanolevel showed that its value varies discretely with an interval equal to l_LF ≈ 100 nm. It was shown that such discreteness is determined by the interval l_LF of the action of adhesive forces F_adh and indicates the fractal nature of the functional dependence of the friction force on the coordinate F_fr = F_fr(x). Thus, for nano-objects with dimensions ≤ l_LF, the absolute value of F_fr decreases according to a power law with an increase in the size of the object, which contradicts the similar dependence of the friction force for macro-objects in the global approximation.

The micronucleus test for the oral mucosa: global trends and new questions

This study reviews global trends in the publication of papers on the micronucleus test of the exfoliated cells of the oral mucosa in mammals as an approach for environmental biomonitoring. This test has been widely used due to its precision for the detection of chromosome damage. Our temporal analysis showed a significant increase (p < 0.05) in the publication of papers on the oral mucosa over the past 33 years. Brazil was the country that published most papers (24% of the total), followed by India (16%), the USA (10%), Mexico (7%), and Turkey (6%). A further 30 countries contributed the other 37% of the papers. Overall, 99% of the micronucleus studies involved human subjects, and only 1% involved other mammals. As many wild mammals are subject to the same environmental pressures as humans, in particular chemical pollution, it seems likely that many species are equally susceptible to genotoxicogical damage. We emphasize the importance of applying this technique to the analysis of the oral mucosa of wild mammals, as well as the evaluation of its effectiveness, as observed in humans, and the expansion of the available approaches to the monitoring of environmental quality.