-
[show abstract]
[hide abstract]
ABSTRACT: The recent development of non-invasive imaging techniques has enabled the visualization of molecular events underlying cellular processes in live cells. Although microscopic objects can be readily manipulated at the cellular level, additional physiological insight is likely to be gained by manipulation of cells in vivo, which has not been achieved so far. Here we use infrared optical tweezers to trap and manipulate red blood cells within subdermal capillaries in living mice. We realize a non-contact micro-operation that results in the clearing of a blocked microvessel. Furthermore, we estimate the optical trap stiffness in the capillary. Our work expands the application of optical tweezers to the study of live cell dynamics in animals.
Nature Communications 04/2013; 4:1768. · 7.40 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: For a triaxial ellipsoid in an optical trap with spherical aberration, the optical forces, torque and stress are analyzed using vectorial ray tracing. The torque will automatically regulate ellipsoid's long axis parallel to optic axis. For a trapped ellipsoid with principal axes in the ratio 1:2:3, the high stress distribution appears in x-z plane. And the optical force at x-axis is weaker than at y-axis due to the shape size. While the ellipsoid departs laterally from trap center, the measurable maximum transverse forces will be weakened due to axial equilibrium and affected by inclined orientation. For an appropriate ring beam, the maximum optical forces are strong in three dimensions, thus, this optical trap is appropriate to trap cells for avoiding damage from laser.
Optics Express 07/2012; 20(14):14928-37. · 3.59 Impact Factor
-
02/2011; , ISBN: 978-953-307-691-1
-
[show abstract]
[hide abstract]
ABSTRACT: A digital micromirror device (DMD) modulates laser intensity through computer control of the device. We experimentally investigate the performance of the modulation property of a DMD and optimize the modulation procedure through image correction. Furthermore, Laguerre-Gaussian (LG) beams with different topological charges are generated by projecting a series of forklike gratings onto the DMD. We measure the field distribution with and without correction, the energy of LG beams with different topological charges, and the polarization property in sequence. Experimental results demonstrate that it is possible to generate LG beams with a DMD that allows the use of a high-intensity laser with proper correction to the input images, and that the polarization state of the LG beam differs from that of the input beam.
Applied Optics 04/2010; 49(10):1838-44. · 1.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Birefringent particles rotate when trapped in elliptically polarized light. When an infinity corrected oil-immersion objective is used for trapping, rotation of birefringent particles in optical tweezers based on an infinity optical microscope is affected by the spherical aberration at the glass-water interface. The maximum rotation rate of birefringent particles occurs close to the coverslip, and the rotation rate decreases dramatically as the trapped depth increases. We experimentally demonstrate that spherical aberration can be compensated by using a finite-distance-corrected objective to trap and rotate the birefringent particles. It is found that the trapped depth corresponding to the maximum rotation rate is 50 microm, and the rotation rates at deep trapped depths are improved.
Applied Optics 09/2009; 48(22):4397-402. · 1.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Traditional solid geometry ray-tracing method is complex in analyzing the orientation of gradient forces and calculating incident angle of optic rays upon a microsphere. We present a new ray-tracing methodology based on spatial analytic geometry in the ray-optic model. For a single ray upon a microsphere, the directions of transmission and trapping forces are depicted by spatial vectors in a Cartesian coordinate system. At the same time, the polarized direction of a single focused ray can be transformed by a matrix of rotational coordinates. According to the relations of vectors, the trapping forces can be expressed identically. We use this new method to discuss differences of trapping forces in the cases of various states of unpolarized and polarized beams, and also show the reasons for differences in transverse force between measurement and theoretical results. Our simulative results show that this method can be applied identically to calculating both transverse and axial trapping forces, and also for different polarizations of a laser beam.
Applied Optics 12/2008; 47(33):6307-14. · 1.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Lymphocyte function associated antigen-1 (CD11a/CD18, LFA-1) plays an important role in the structure of the immunological synapse and is required for efficient lysis of cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. To study the activation mode of LFA-1 on the NK cell surface, optical tweezers were used in the work. As an emerging technology, optical tweezers are widely used to manipulate microscopic objects and measure the forces of molecular interactions in the field of biological research. In our study, a new platform was constructed to study the single molecular behavior of receptor on cell surface using optical tweezers. Based on the platform, the interaction between an NK cell and a polystyrene microsphere coated with anti-LFA-1 antibody was observed. The result confirmed that the adhesion forces between an NK cell and a polystyrene bead were time-dependent. According to our findings, we propose that anti-LFA-1 antibody may cause the clustering of LFA-1 on NK cell surface.
Cellular & molecular immunology 07/2007; 4(3):221-5. · 2.99 Impact Factor
-
Acta Physica Sinica -Chinese Edition- 59(6):3930-3935. · 1.03 Impact Factor
-
Chinese Physics Letters 27(2):028703. · 0.73 Impact Factor
-
Chinese Optics Letters 8(2):170-172. · 0.97 Impact Factor
