Many biological microswimmers are capable of chemotaxis, , they can sense an ambient chemical gradient and adjust their mechanism of motility to move towards or away from the source of the gradient. Synthetic active colloids endowed with chemotactic behavior hold considerable promise for targeted drug delivery and the realization of programmable and reconfigurable materials. Here, we study the chemotactic behavior of a Janus particle, which converts "fuel" molecules, released at an axisymmetric chemical patch located on a planar wall, into "product" molecules at its catalytic cap and moves by self-phoresis induced by the product. The chemotactic behavior is characterized as a function of the interplay between the rates of release (at the patch) and the consumption (at the particle) of fuel, as well as of details of the phoretic response of the particle (, its phoretic mobility). Among other results, we find that, under certain conditions, the particle is attracted to a stable "hovering state" in which it aligns its axis normal to the wall and rests (positions itself) at an activity-dependent distance above the center of the patch.
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http://dx.doi.org/10.1039/d4sm00733f | DOI Listing |
Mol Biol Cell
December 2024
Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan.
The question of how changes in chemoattractant concentration translate into the chemotactic response of immune cells serves as a paradigm for the quantitative understanding of how cells perceive and process temporal and spatial information. Here, using a microfluidic approach, we analyzed the migration of neutrophil-like HL-60 cells to a traveling wave of the chemoattractants fMLP and leukotriene B4 (LTB4). We found that under a pulsatile wave that travels at a speed of 95 and 170 µm/min, cells move forward in the front of the wave but slow down and randomly orient at the back due to temporal decrease in the attractant concentration.
View Article and Find Full Text PDFResearch (Wash D C)
December 2024
School of Medicine and Health, Harbin Institute of Technology, Harbin 150001, China.
Living microorganisms can perform directed migration for foraging in response to a chemoattractant gradient. We report a biomimetic strategy that rotary FF-ATPase (adenosine triphosphatase)-propelled flasklike colloidal motors exhibit positive chemotaxis resembling the chemotactic behavior of bacteria. The streamlined flasklike colloidal particles are fabricated through polymerization, expansion, surface rupture, and re-polymerizing nanoemulsions composed of triblock copolymers and ribose.
View Article and Find Full Text PDFEnviron Microbiol
December 2024
School of Life Sciences, Joseph Banks Laboratories, University of Lincoln, Lincoln, UK.
Elongated morphologies are prevalent among motile bacterioplankton in aquatic systems. This is often attributed to enhanced chemotactic ability, but how long is best? We hypothesized the existence of an optimal cell length for efficient chemotaxis resulting from shape-imposed physical constraints acting on the trade-off between rapid exploration versus efficient exploitation of nutrient sources. To test this hypothesis, we evaluated the chemotactic performance of elongated cephalexin-treated Escherichia coli towards α-methyl-aspartate in a microfluidic device creating linear, stable and quiescent chemical gradients.
View Article and Find Full Text PDFFront Immunol
December 2024
Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Xinxiang, Henan, China.
Small
November 2024
BMI Center for Biomass Materials and Nanointerfaces, National Engineering Laboratory for Clean Technology of Leather Manufacture, Ministry of Education Key Laboratory of Leather Chemistry and Engineering, College of Biomass Science and Engineering, Sichuan University, Chengdu, Sichuan, 610065, China.
Cells existing in the form of clusters often exhibit distinct biological functions from their single-cell counterparts. However, the ability to modulate cell-cell interactions among multiple cell types through molecular scaffolds remains an ongoing challenge. Here, a supramolecular phenolic network on surfaces of live cells designed is engineered to act as modular scaffolds that promote intercellular interactions, presenting a universal platform for the construction of cell-cell assemblies (CCAs).
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