Physical grounds for biological effect of laser radiation

Abstract

A new approach to the understanding of biological activity caused by low-intensity laser radiation, in which coherence is a factor of paramount importance, has been developed. It is based on the dipole interaction of gradient laser fields with cells, organelles and membranes. The laser intensity gradients in an object arise due to the interference of the light scattered by the tissue with the incident light beam (speckle formation). Apart from speckles, different types of light spatial modulation can be created deliberately using different schemes for beam interference.It is shown that gradient laser fields may cause spatial modulation of the concentration of particles and increase their ‘partial temperature’. This paper presents the results of experimental observation of trapping of different types of particles, including human lymphocytes, in the interference fields of the He–Ne laser. The sweep-net effect on particles of different sizes on moving the laser field is demonstrated and crystal-like self-organization of particles in the laser gradient field is observed.The influence of gradient laser fields on erythrocyte rouleaus, on the apoptosis of human lymphocytes as well as on their chromosome aberrations is demonstrated. It may be concluded from the experimental studies that the influence of an interference laser field with a rightly chosen period can stimulate the repair system of a cell, increasing its viability.

Changes in the germination process and growth of pea in effect of laser seed irradiation

“…We know at present that laser stimulation enables the seed cell to absorb and store radiant energy, which is then converted to chemical energy as a useable form in subsequent growth processes (Jamil et al, 2013). The above observation is substantiated by studies that confirmed the positive effects of laser radiation on enzyme activity at the early stages of germination (Chen et al, 2005b;Perveen et al, 2010;Rubinov, 2003).…”

“…However, according to some authors, the best method to combine these goals is the use of physical treatments (Delibatowa and Ivanova, 2006;Flórez et al, 2007;Hernandez et al, 2010;Jun et al, 2007;Rochalska and Orzeszko-Rywka, 2008). In some researches opinion, presowing physical treatments of seeds are environmentally safe because they only modify biochemical and physiological processes in seeds, which, in consequence, accelerate seedling emergence and improve plant development (Chen et al, 2005a;Podleśny et al, 2012;Rubinov, 2003). Physical treatments, such as laser irradiation, do not replace chemical methods, but they can supplement them (Ouf and Abdel-Hardy, 1999;Vasilevski, 2003).…”

Orientation of Red Blood Cells and Rouleaux Disaggregation in Interference Laser Fields

“…There are two main approaches towards multiple optical trapping: one based on strongly focused beams using the high numerical aperture objectives [6][7][8][9][10] and another based on interference methods when particles are trapped by interference field [11][12][13][14][15][16][17]. The first type systems were created by a number of means: by fast single beam scanning [6], by two counterpropagating Gaussian light beams [7], with methods of spatial light modulation, e.g., computer-generated holography [8] or generalized phase-contrast method [9], and with multiple light sources [10].…”

“…These advantages and possibilities make the interferometric technique a promising tool for the high speed operation with multicomponent suspensions and tissues. For instance, the selective capture and transportation of particles of different sizes by means of a moving interference field (the 'optical sweep-net' [17]) opens up interesting possibilities for biological applications. In particular, applications such as stimulation of blood transportation through microcapillaries, sorting and separation of lymphocytes, RBCs or other particles etc are expected.…”

“…Our previous paper [17] deals with the influence of interference laser fields on cells of human blood. We have demonstrated the trapping of lymphocytes and RBCs in interference fringes, and the influence of interference period on the lymphocyte apoptosis.…”