Intracellular trafficking mainly takes place along the microtubules, and its efficiency depends on the local architecture and organization of the cytoskeletal network. In this work, the cytoplasm of stem cells is subjected to mechanical vortexing at a frequency of up to 1 Hz, by using magnetic chains of endosomes embedded in the cell body, in order to locally perturb the network structure. The consequences are evaluated on the directionality and processivity of the spontaneous motion of endosomes. When the same chains are used both to shear the cell medium and to probe the intracellular traffic, a substantial decrease in transport efficiency is detected after applying the mechanical shear. Interestingly, when using different objects to apply the shear and to probe the spontaneous motion, no alteration of the transport efficiency can be detected. We conclude that shaking the vesicles mainly causes their unbinding from the cytoskeletal tracks, but has little influence on the integrity of the network itself. This is corroborated by active microrheology measurements, performed with chains actuated by a magnetic field, and showing that the mechanical compliance of the cytoplasm is similar before and after slow vortexing.
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http://dx.doi.org/10.1039/c7sm00732a | DOI Listing |
iScience
January 2025
School of Civil Engineering and Architecture, Zhejiang University of Science & Technology, Hangzhou, P.R. China.
A possibility of unprecedented architecture may be opened up by combining both vertical and in-plane heterostructures. It is fascinating to discover that the interlayer stress transfer, interlayer binding energy, and interlayer shear stress of bi-layer Gr/hBN with CNTs heterostructures greatly increase (more than 2 times) with increase the numbers of CNTs and both saturate at the numbers of CNTs = 3, but it causes only 10.92% decrease in failure strain.
View Article and Find Full Text PDFWearable Technol
December 2024
Robotics Research Centre, School of Mechanical and Aerospace Engineering, NTU, Singapore.
Pathological tremors can often be debilitating to activities of daily living and significantly affect the quality of life. Such tremulous movements are commonly observed in wrist flexion-extension (FE). To suppress this tremor we present a wearable robot (WR) with a customized mechanical metamaterial (MM) as the physical human-robot interface (pHRI).
View Article and Find Full Text PDFACS Nano
January 2025
Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium.
The iron-regulated surface determinant protein B (IsdB) has recently been shown to bind to toll-like receptor 4 (TLR4), thereby inducing a strong inflammatory response in innate immune cells. Currently, two unsolved questions are (i) What is the molecular mechanism of the IsdB-TLR4 interaction? and (ii) Does it also play a role in nonimmune systems? Here, we use single-molecule experiments to demonstrate that IsdB binds TLR4 with both weak and extremely strong forces and that the mechanostability of the molecular complex is dramatically increased by physical stress, sustaining forces up to 2000 pN, at a loading rate of 10 pN/s. We also show that TLR4 binding by IsdB mediates time-dependent bacterial adhesion to endothelial cells, pointing to the role of this bond in cell invasion.
View Article and Find Full Text PDFComput Biol Med
January 2025
Department of Biomedical Engineering, Faculty of Science and Engineering, Swansea University, Swansea, United Kingdom; Zienkiewicz Institute for Modelling Data and AI, Swansea University, Swansea, United Kingdom. Electronic address:
Most cell types are mechanosensitive, their activities such as differentiation, proliferation and apoptosis, can be influenced by the mechanical environment through mechanical stimulation. In three dimensional (3D) mechanobiological in vitro studies, the porous structure of scaffold controls the local mechanical environment that applied to cells. Many previous studies have focused on the topological design of homogeneous scaffold struts.
View Article and Find Full Text PDFHeliyon
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.
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