Local scattering stress distribution on surface of a spherical cell in optical stretcher

Abstract

We calculate stress distribution on the surface of a spherical cell trapped by two counter propagating beams in the optical stretcher in the ray optics regime. We demonstrate that the local scattering stress is perpendicular to the spherical refractive surface regardless of incident angle, polarization and the reflectance and transmittance at the surface. We explain the apparition of peaks in the stress distribution, which were not revealed in the existing theory. We consider the divergence of the incident beams from the fibers, and express the stress distribution as a function of fiber-to-cell distance. The new theory can predict the cell's deformation more precisely.

Reconfigurable microfluidic integration of a dual-beam laser trap with biomedical applications

“…Apart from the use for diagnosing cancer, the optical stretcher is finding an increasing number of applications in biomedical and biophysical research (Singer et al 2003;Liu et al 2006;Bareil et al 2006). Additionally, for nondeformation purposes, the dual-beam laser trap is gaining importance relative to the all-pervasive optical tweezers as evidenced by recent theoretical and experimental studies (Gauthier et al 2003;Wei et al 2006;Jess et al 2006;Cran-McGreehin et al 2006).…”

Optical separation of ellipsoidal particles in a uniform flow

“…Among the various applications of the laser light, the optical force can be utilized to manipulate micro-sized objects in a non-contacting manner, 3 e.g., to trap single cells or particles [4][5][6] and to separate multiple cells or particles, [7][8][9][10][11][12][13][14] as first demonstrated in the pioneering work of Ashkin. 15 In conjunction with the experimental approaches, theoretical models were developed, which were categorized according to the particle size.…”

“…The optical force on the particle much smaller than the wavelength was obtained by the Rayleigh dipole approximation, 16 while that on the particle much larger than the wavelength was calculated by the ray optics method. 5,6,12,[17][18][19][20][21][22] For the optical force on the particle with arbitrary size including the intermediate one, the generalized Lorenz-Mie theory was employed. 23,24 Among these methods, the ray optics method is relatively simple, and covers the size range of most blood cells, i.e., red blood cell and white blood cell.…”

Effect of N‐ethylmaleimide, chymotrypsin, and H2O2 on the viscoelasticity of human erythrocytes: Experimental measurement and theoretical analysis

“…Several methods have been developed to apply an external force to a biological cell either locally or distributed over the cell to probe its mechanical response [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. These methods include optical magnetic twisting cytometry [3], optical tweezers with micro-beads (serving as handles) attached to RBCs [4,[12][13][14], optical tweezers dragging RBCs through viscous fluid [5], dual-trap optical tweezers [6], optical stretcher [7][8][9], micropipette aspiration [10,11], RBC bending and relaxation via optical tweezers with triple-focal spots [15], and the RBC deformation and relaxation in a parallel-plate flow chamber [16]. Each of these methods has certain advantages and limitations, and often complements each other.…”