Cold atmospheric plasma (CAP) is a 'partially ionized' gas composed of free electrons, positive and negative ions, radicals, excited species, an electric field, and ultraviolet radiation (UVR) [1][2][3][4]. One of the most important advantages of cold plasma is its ability to work at room temperature and atmospheric pressure, which makes it possible to be utilized in biological media with minimal thermal side effects [5][6][7][8]. In this regard, the prominent applications of CAP are microorganism

Nonlinear heating of collisional plasma when the temporal extent of the laser pulse is smaller than the ambipolar diffusion time has been investigated. The nonlinearity in a collisionless plasma arises through the ponderomotive force, whereas in collisional plasmas ohmic nonlinearity prevails. In this case, by considering the nonrelativistic ponderomotive force effect and the variation of the collision frequency between electrons and ions due to the temperature change, the nonlinear dielectric permittivity of the plasma medium is obtained and the equation of the electromagnetic wave propagation in underdense plasma is solved. It is shown that in this case, due to the ohmic heating of electrons, the effect of the ponderomotive force in the nonrelativistic regime leads to steepening of the electron density profile and decreases the temperature of the plasma electrons noticeably. Bunches of electrons in plasma become narrower and by increasing the laser pulse strength the wavelength of density oscillations decreases. In this regime of laser–plasma interaction, the electron temperature decreases sharply with increasing the intensity of laser pulses.

Cold atmospheric plasma has established its effect on cell adhesion. Given the importance of cell adhesion in stem cells, the current study investigates the effect of plasma treatment on Human Bone Marrow Mesenchymal Stem Cells (HBMMSCs) adhesion by which the differentiation and fate of cells are determined. In this paper, adhesion modification is considered not only for cell- ECM (Extra cellular Matrix), but also between suspended cells, and enhanced adhesions were found in both circumstances. Regarding the previous works, the increase of the cell–ECM adhesion during the plasma therapy was mostly attributed to the enhancement of the production and activity of integrin proteins. Nevertheless, considering the importance of van der Waals forces at the cellular level, the effect of cold plasma on VDWFs and so its effect on adhesion is investigated in this work for the first time, to the best of our knowledge. For this purpose, employing the semi-empirical methods, the role of the plasma therapy on the VDWF between the cells has been studied at three levels; (a) plasma-induced dipole formation, (b) Hammaker coefficient modification of culture medium, and c) cell roughness modification. For suspended cell condition, we conclude and support that van der Waals forces (VDWFs) enhancement has a key role in cell adhesion processes. We believe that, the present work gives a new physical insight in studying the plasma therapy method at the cellular level.