Microorganisms navigate through complex environments such as biofilms and mucosal tissues and tracts. To understand the effect of a complex medium upon their locomotion, we investigate numerically the effect of fluid viscoelasticity on the dynamics of an undulating swimming sheet. First, we recover recent small-amplitude results for infinite sheets that suggest that viscoelasticity impedes locomotion. We find the opposite result when simulating free swimmers with large tail undulations, with both velocity and mechanical efficiency peaking for Deborah numbers near one. We associate this with regions of highly stressed fluid aft of the undulating tail.
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http://dx.doi.org/10.1103/PhysRevLett.104.038101 | DOI Listing |
Pharmaceutics
January 2025
Department of Mathematics, Visva-Bharati University, Santiniketan 731235, WB, India.
Microneedle(MN)-based drug delivery is one of the potential approaches to overcome the limitations of oral and hypodermic needle delivery. An in silico model has been developed for hollow microneedle (HMN)-based drug delivery in the skin and its subsequent absorption in the blood and tissue compartments in the presence of interstitial flow. The drug's reversible specific saturable binding to its receptors and the kinetics of reversible absorption across the blood and tissue compartments have been taken into account.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Food Science, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. Electronic address:
In this experiment, the effects of different concentrations of cassava starch (CS) on the gel behavior of faba bean protein (FBP) were studied, focusing on the structural characteristics, gel characteristics and physical and chemical characteristics of the gel system. Specifically, with the increase of CS concentration from 4 % to 12 %, the morphology of the sample changed from fluid to gel solid. From the molecular structure, different concentrations of CS affected the secondary and tertiary structures of FBP protein, which made aromatic amino acids move to the surface of protein and promoted the transformation from α-helix to β-sheet.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill 27599, United States.
Architecturally hindered crystallization of bottlebrush graft copolymers offers a reaction- and solvent-free pathway for creating injectable elastomers with tissue-mimetic softness. Currently, injectable materials involve solvents and chemical reactions, leading to uncontrolled swelling, leaching of unreacted moieties, and side reactions with tissue. To address this issue, bottlebrush copolymers with a poly(ethylene glycol) (PEG) amorphous block and crystallizable poly(lactic acid) (PLA) grafted chains (A--B) were synthesized, with grafted chains of controlled length arranged along the backbone at controlled spacing.
View Article and Find Full Text PDFSoft Matter
January 2025
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
The capillary break-up of complex fluid filaments occurs in many scientific and industrial applications, particularly in bio-printing where both liquid and polymerized droplets exist in the fluid. The simultaneous presence of fluid and solid particles within a carrier fluid and their interactions lead to deviations in the filament break-up from the well-established capillary breakup dynamics of single-phase liquids. To examine the significance of the dispersed phase and the internal interactions between liquid droplets and solid particles, we prepare emulsions through photopolymerization and conduct experimental investigations into the pinch-off dynamics of fluid filaments, focusing on the impact of varying concentrations of liquid droplets (before polymerization) and polymerized droplets.
View Article and Find Full Text PDFBiophys Rev
December 2024
Macromolecular Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
Cells and tissues are often under some level of confinement, imposed by the microenvironment and neighboring cells, meaning that there are limitations to cell size, volume changes, and fluid exchanges. 3D cell culture, increasingly used for both single cells and organoids, inherently impose levels of confinement absent in 2D systems. It is thus key to understand how different levels of confinement influences cell survival, cell function, and cell fate.
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