A spatial light modulator (SLM) and a pair of galvanometer-mounted mirrors (GMM) were combined into an optical tweezers setup. This provides great flexibility as the SLM creates an array of traps, which can be moved smoothly and quickly with the GMM. To optimize performance, the effect of the incidence angle on the SLM with respect to phase and intensity response was investigated. Although it is common to use the SLM at an incidence angle of 45 degrees, smaller angles give a full 2pi phase shift and an output intensity which is less dependent on the magnitude of the phase shift. The traps were calibrated using an active oscillatory technique and a passive probability distribution method.
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http://dx.doi.org/10.1063/1.3196181 | DOI Listing |
Nat Commun
January 2025
Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei, China.
The spin angular momentum (SAM) plays a significant role in light-matter interactions. It is well known that light carrying SAM can exert optical torques on micro-objects and drive rotations, but 3D rotation around an arbitrary axis remains challenging. Here, we demonstrate full control of the 3D optical torque acting on a trapped microparticle by tailoring the vectorial SAM transfer.
View Article and Find Full Text PDFJ Med Life
November 2024
Biophysics and Cellular Biotechnology Department, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
Optical tweezers, which leverage the forces exerted by radiation pressure, have emerged as a pivotal technique for precisely manipulating and analyzing microscopic particles. Since Arthur Ashkin's ground-breaking work in the 1970s and the subsequent development of the single-beam optical trap in 1986, the capabilities of optical tweezers have expanded significantly, enabling the intricate manipulation of biological specimens at the micro- and nanoscale. This review elucidates the foundational principles of optical trapping and their extensive applications in the biomedical sciences.
View Article and Find Full Text PDFBiomech Model Mechanobiol
January 2025
CNR Istituto Officina Dei Materiali, Area Science Park Basovizza, S.S. 14, Km 163,5, 34149, Trieste, Italy.
The organization and dynamics of the spectrin-actin membrane cytoskeleton play a crucial role in determining the mechanical properties of red blood cells (RBC). RBC are subjected to various forces that induce deformation during blood microcirculation. Such forces also regulate membrane tension, leading to Piezo1 channel activation, which is functionally linked to RBC dehydration through calcium influx and subsequent activation of Gardos channels, ultimately resulting in variations in RBC volume.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155, USA.
The electric fields of tightly focused laser beams can be strong enough to apply appreciable force to microscopic objects, including biological entities such as cells, bacteria, and even viruses and biomolecules [...
View Article and Find Full Text PDFImmunol Rev
December 2024
Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
αβT cells protect vertebrates against many diseases, optimizing surveillance using mechanical force to distinguish between pathophysiologic cellular alterations and normal self-constituents. The multi-subunit αβT-cell receptor (TCR) operates outside of thermal equilibrium, harvesting energy via physical forces generated by T-cell motility and actin-myosin machinery. When a peptide-bound major histocompatibility complex molecule (pMHC) on an antigen presenting cell is ligated, the αβTCR on the T cell leverages force to form a catch bond, prolonging bond lifetime, and enhancing antigen discrimination.
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