Anisotropic nematic gels are prepared via in situ polymerization of diacrylate monomers in an oriented nematic liquid crystal (LC) matrix. The structure of the gels is studied from micrometer to nanometer scales by optical microscopy, small angle neutron scattering, and theta/2theta light scattering. A strong anisotropy is evidenced at all scales without electric field for both mesogenic and nonmesogenic monomers. The gel network can be pictured as an ordered but strongly distorted and polydisperse structure with two characteristic sizes: the mean size of the polymer objects and a correlation length between these objects, corresponding to the mean-size of the LC domains, which are estimated from neutron and light scattering results to be of the order of some tens of nanometers and some micrometers, respectively. Moreover, a sheet-like structure of the polymer network is evidenced. When an electric field is applied, one part of the LC switches while the other part remains anchored to the polymer network. The electric field dependence of the volume fraction of anchored LC is estimated from the analysis of the light scattering data. We emphasize systematic correlations between structure and electro-optical properties of the gels.
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http://dx.doi.org/10.1103/PhysRevE.68.011709 | DOI Listing |
Light Sci Appl
January 2025
Britton Chance Center for Biomedical Photonics-MoE Key Laboratory for Biomedical Photonics, Advanced Biomedical Imaging Facility-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
Optical imaging plays a central role in the field of biomedicine, but it suffers from the light scattering of tissues. The research group from Stanford University has reported a counterintuitive observation that strongly absorbing molecules could achieve optical transparency in live animals, providing a new insight for understanding tissue optical clearing. It empowers scientists to leverage optical imaging techniques for in vivo observation of a wide range of deep-seated structures and activities.
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January 2025
Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.
In recent advancements in life sciences, optical microscopy has played a crucial role in acquiring high-quality three-dimensional structural and functional information. However, the quality of 3D images is often compromised due to the intense scattering effect in biological tissues, compounded by several issues such as limited spatiotemporal resolution, low signal-to-noise ratio, inadequate depth of penetration, and high phototoxicity. Although various optical sectioning techniques have been developed to address these challenges, each method adheres to distinct imaging principles for specific applications.
View Article and Find Full Text PDFPLoS One
December 2024
Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, Texas, United States of America.
The accurate characterization of microtubules is essential for understanding their roles in various biological activities in eukaryotic cellular processes. In vitro, experimental data on these systems often need more details and information on sample preparation protocols and experimental techniques. This deficiency leads to unreproducible or contradictory outcomes.
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December 2024
Structure and Cell Biology of Viruses Lab, CIC bioGUNE - Basque Research and Technology Alliance, Derio, Spain.
A virus particle must work as a strongroom to protect its genome, but at the same time it must undergo dramatic conformational changes to infect the cell in order to replicate and assemble progeny. Thus, viruses are miniaturized wonders whose structural complexity requires investigation by a combination of different techniques that can tackle both static and dynamic processes. In this chapter, we will illustrate how major structural techniques such as X-ray crystallography and electron microscopy can be combined with other techniques to determine the structure of complex viruses.
View Article and Find Full Text PDFSci Rep
December 2024
Pharmacy Department, Hospices Civils de Lyon, Hôpital E. Herriot, Plateforme FRIPHARM, 69437, Lyon, France.
Phage therapy uses viruses (phages) against antibiotic resistance. Tailoring treatments to specific patient strains requires stocks of various highly concentrated purified phages. It, therefore, faces challenges: titration duration and specificity to a phage/bacteria couple; purification affecting stability; and highly concentrated suspensions tending to aggregate.
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