We develop an extension of fluorescence correlation spectroscopy (FCS) using a spinning disk confocal microscope. This approach can spatially map diffusion coefficients or flow velocities at up to approximately 10(5) independent locations simultaneously. Commercially available cameras with frame rates of 1000 Hz allow FCS measurements of systems with diffusion coefficients D~10(-7) cm(2)/s or smaller. This speed is adequate to measure small microspheres (200-nm diameter) diffusing in water, or hindered diffusion of macromolecules in complex media (e.g., tumors, cell nuclei, or the extracellular matrix). There have been a number of recent extensions to FCS based on laser scanning microscopy. Spinning disk confocal microscopy, however, has the potential for significantly higher speed at high spatial resolution. We show how to account for a pixel size effect encountered with spinning disk confocal FCS that is not present in standard or scanning FCS, and we introduce a new method to correct for photobleaching. Finally, we apply spinning disk confocal FCS to microspheres diffusing in Type I collagen, which show complex spatially varying diffusion caused by hydrodynamic and steric interactions with the collagen matrix.
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http://dx.doi.org/10.1529/biophysj.106.084251 | DOI Listing |
Heliyon
January 2025
Institute of Mathematics, Henan Academy of Sciences, Zhengzhou, 450046, China.
This study examines the behavior of the Casson nanofluid bioconvection flow around a spinning disc under various influences, including gyrotactic microorganisms, multiple slips, and thermal radiation. Notably, it accounts for the reversible nature of the flow and incorporates the esterification process. The aim of this study is to investigate the influence of reversible chemical reactions on the flow behavior of a Casson nanofluid in the presence of bioconvective microorganisms over a spinning disc.
View Article and Find Full Text PDFSpinning coding masks, recognized for their fast modulation rate and cost-effectiveness, are now often used in real-time single-pixel imaging (SPI). However, in the photon-counting regime, they encounter difficulties in synchronization between the coding mask patterns and the photon detector, unlike digital micromirror devices. To address this issue, we propose a scheme that assumes a constant disk rotation speed throughout each cycle and models photon detection as a non-homogeneous Poisson process (NHPP).
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Exploratory Research Center on Life and Living Systems, National Institute of Natural Sciences, Okazaki, Japan.
Int J Mol Sci
November 2024
Institute of Biomedical and Oral Research (IBOR), Faculty of Dental Medicine, The Hebrew University of Jerusalem, Ein Kerem Campus, Jerusalem 9112102, Israel.
Background: and are Gram-positive bacteria involved in the development of dental caries, as they are able to form biofilms on tooth enamel, ferment sugars into acids, and survive under acidic conditions. This ultimately leads to a local lowering of the pH value on the tooth surface, which causes enamel cavities.
Hypothesis: One measure to reduce caries is to limit the growth of cariogenic bacteria by using two anti-bacterial agents with different mechanisms of action.
Int J Biol Macromol
December 2024
Key Laboratory of Industrial Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China; Shandong Academy of Pharmaceutical Sciences, Shandong Key Laboratory of Mucosal and Skin Drug Delivery Technology, Jinan 250101, China. Electronic address:
Timely healing of acute wounds and stopping wound chronicity are current and future priorities in wound therapy. It is urgent and relevant to develop a wound dressing that has antimicrobial and monitors the wound microenvironment in real time. In this study, quaternary ammonium chitosan (HTCC) was selected as the antimicrobial agent and CS/PEO/HTCC nanofiber membranes (CPHs) were prepared by electrostatic spinning technique.
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