Selectin/ligand interaction plays an important role in such biological processes as inflammatory reaction, tumor metastasis, etc. External forces affect dissociation of receptor-ligand bonds. A novel approach, upon optical trap technique, was developed in this study to investigate the dissociation of P-selectin/PSGL-1 (P-Selectin Glycoprotein Ligand 1) bindings. Stiffness of optical trap was calibrated with laser power using a viscous drag method. While P-selectin and PSGL-1 molecules were functionally coated on surfaces of glass beads, respectively, the dissociation of interacting molecule bond was studied by measuring the rupture force distribution. It was found that most probable rupture force increased with loading rate at < 25 pN/s. These results complemented and validated the current theory at low loading rates.
Download full-text PDF |
Source |
---|
Phys Rev Lett
December 2024
Columbia University, Department of Physics, New York, New York 10027, USA.
We report on the optical polarizability of microwave-shielded ultracold NaCs molecules in an optical dipole trap. While dressing a pair of rotational states with a microwave field, we observe a marked dependence of the optical polarizability on the intensity and detuning of the dressing field. To precisely characterize differential energy shifts between dressed rotational states, we establish dressed-state spectroscopy.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Wyant College of Optical Sciences, University of Arizona, 1630 E University Blvd, Tucson, AZ, USA.
Nanophotonic devices control and manipulate light at the nanometer scale. Applications include biological imaging, integrated photonic circuits, and metamaterials. The design of these devices requires the accurate modeling of light-matter interactions at the nanoscale and the optimization of multiple design parameters, both of which can be computationally demanding and time intensive.
View Article and Find Full Text PDFWe present a dual isotope magneto-optical trap (MOT), simultaneous sub-Doppler laser cooling, and magnetic trapping of a spin-polarized K-K Bose-Fermi mixture realized in a single-chamber setup with an unenriched potassium dispenser as the source of atoms. We are able to magnetically confine more than 2.2 × 10 fermions ( = 9/2 , = 9/2) and 1.
View Article and Find Full Text PDFInnovation (Camb)
January 2025
Center for Intelligent Biomedical Materials and Devices (IBMD), Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen 518055, China.
Optical tweezers and related techniques offer extraordinary opportunities for research and applications in physical, biological, and medical fields. However, certain critical requirements, such as high-intensity laser beams, sophisticated electrode designs, additional electric sources, or low-conductive media, significantly impede their flexibility and adaptability, thus hindering their practical applications. Here, we report innovative photopyroelectric tweezers (PPT) that combine the advantages of light and electric field by utilizing a rationally designed photopyroelectric substrate with efficient and durable photo-induced surface charge-generation capability, enabling diverse manipulation in various working scenarios.
View Article and Find Full Text PDFJ Biol Phys
January 2025
Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, 100190, China.
Conventional kinesin protein is a prototypical biological molecular motor that can step processively on microtubules towards the plus end by hydrolyzing ATP molecules, performing the biological function of intracellular transports. An important characteristic of the kinesin is the load dependence of its velocity, which is usually measured by using the single molecule optical trapping method with a large-sized bead attached to the motor stalk. Puzzlingly, even for the same kinesin, some experiments showed that the velocity is nearly independent of the forward load whereas others showed that the velocity decreases evidently with the increase in the magnitude of the forward load.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!