Revealing viscoelastic bending relaxation dynamics of isolated semi-flexible colloidal polymers

Soft Matter ◽  
2021 ◽  
Author(s):  
Simon Stuij ◽  
Hannah Jonas ◽  
Zhe Gong ◽  
Stefano Sacanna ◽  
Tom Kodger ◽  
...  
Keyword(s):  
Crucial Role ◽  
Viscoelastic Properties ◽  
Colloidal Particles ◽  
Biological Materials ◽  
Relaxation Dynamics

The viscoelastic properties of filaments and biopolymers play a crucial role in soft and biological materials from biopolymer networks to novel synthetic metamaterials. Colloidal particles with specific valency allow mimicking...

The Effect of Refrigerated Storage on the Rheological Properties of Three Commercial Mozzarella Cheeses

2008 ◽  
Vol 4 (4) ◽  
Author(s):  
Edward B Muliawan ◽  
Savvas G Hatzikiriakos
Keyword(s):  
Rheological Properties ◽  
Viscoelastic Properties ◽  
Elevated Temperatures ◽  
Maxwell Model ◽  
Model Parameters ◽  
Refrigerated Storage ◽  
Mozzarella Cheese ◽  
Relaxation Dynamics ◽  
Generalized Maxwell Model ◽  
Linear Viscoelastic

The linear and non-linear viscoelastic properties and the effect of refrigerated storage on the rheological properties of three commercial mozzarella cheeses was studied. The linearity of the rheological behavior of mozzarella cheese increases with temperature because of the ability for the cheese to flow easier at higher temperatures as well as the lack of yield stress at elevated temperatures. The generalized Maxwell model parameters obtained from the linear viscoelastic data were found to describe the linear relaxation dynamics of the mozzarella cheese satisfactorily. It is also shown that the damping function of mozzarella cheese, which is a measure of the degree of non-linearity, can be described by a generalized Zapas model. Although, the different commercial mozzarella cheeses do not exhibit linear viscoelastic differences at room temperature, they do show significant differences at 60°C. The effect of refrigerated storage on the linear viscoelastic properties is brand-dependent and indicates structural differences among cheese samples. Finally it is shown that the dynamic moduli decrease with longer refrigerated storage due to proteolysis activities and/or weakening of the casein matrix.

scholarly journals Optical trapping and critical Casimir forces

2021 ◽  
Vol 136 (2) ◽  
Author(s):  
Agnese Callegari ◽  
Alessandro Magazzù ◽  
Andrea Gambassi ◽  
Giovanni Volpe
Keyword(s):  
Optical Tweezers ◽  
Crucial Role ◽  
Order Parameter ◽  
Optical Trapping ◽  
Colloidal Particles ◽  
Casimir Forces ◽  
Self Assembled ◽  
Experimental Challenge

AbstractCritical Casimir forces emerge between objects, such as colloidal particles, whenever their surfaces spatially confine the fluctuations of the order parameter of a critical liquid used as a solvent. These forces act at short but microscopically large distances between these objects, reaching often hundreds of nanometers. Keeping colloids at such distances is a major experimental challenge, which can be addressed by the means of optical tweezers. Here, we review how optical tweezers have been successfully used to quantitatively study critical Casimir forces acting on particles in suspensions. As we will see, the use of optical tweezers to experimentally study critical Casimir forces can play a crucial role in developing nano-technologies, representing an innovative way to realize self-assembled devices at the nano- and microscale.

Dynamic electric-field-induced response of charged spherical colloids in uncharged hydrogels

2009 ◽  
Vol 640 ◽  
pp. 357-400 ◽  
Author(s):  
MU WANG ◽  
REGHAN J. HILL
Keyword(s):  
Viscoelastic Properties ◽  
Soft Matter ◽  
Colloidal Particles ◽  
Theoretical Study ◽  
Physicochemical Characteristics ◽  
Hydrodynamic Characteristics ◽  
Induced Response ◽  
Complex Frequency ◽  
Polymer Interface ◽  
Polymeric Hydrogels

Embedding colloidal particles in polymeric hydrogels often endows the polymer skeleton with appealing characteristics for microfluidics and biosensing applications. This theoretical study provides a rigorous foundation for interpreting active electrical microrheology and electroacoustic experiments on such materials. In addition to viscoelastic properties of the composites, these techniques sense physicochemical characteristics of the particle–polymer interface. Wang & Hill (Soft Matter, vol. 4, 2008, p. 1048) studied the steady response of a rigid, impenetrable sphere in a compressible hydrogel skeleton. Here, we extend their analysis to arbitrary frequencies, showing, in general, how the frequency response depends on the particle size and charge, ionic strength of the electrolyte and elastic and hydrodynamic characteristics of the polymer skeleton. Our calculations capture the transition from quasi-steady compressible to quasi-steady incompressible dynamics as the frequency passes through the reciprocal draining time of the gel. Above the reciprocal draining time, the skeleton and fluid move in unison, so the dynamics are incompressible and, thus, given to an excellent approximation by the well-known dynamic electrophoretic mobility but with the Newtonian shear viscosity replaced by a complex, frequency-dependent value.

scholarly journals Optical trapping of nucleolus reveals viscoelastic properties of nucleoplasm inside mouse germinal vesicle oocytes

2020 ◽  
Author(s):  
Maria S. Syrchina ◽  
Aleksander M. Shakhov ◽  
Arseny V. Aybush ◽  
Victor A. Nadtochenko
Keyword(s):  
Germ Cells ◽  
Viscoelastic Properties ◽  
Optical Trapping ◽  
Near Infrared ◽  
Germinal Vesicle ◽  
Relaxation Dynamics ◽  
Equilibrium System ◽  
Biophysical Properties ◽  
Cell Interior ◽  
Hoechst 33342

ABSTRACTWe propose a technique of controlled manipulation with mammalian intracellular bodies by means of optical trapping in order to reveal viscoelastic properties of cell interior. Near infrared laser in the spectral range of tissue transparency was applied to study dynamics of the nucleolus-chromatin complex inside the thermodynamically non-equilibrium system of a mouse oocyte. A nucleolus of germinal vesicle (GV) oocyte as spherical probe was displaced from the equilibrium and its relaxation dynamics was observed. We developed software for subdiffraction tracking of a nucleolus position with lateral resolution up to 3 nm and applied it for different GV-oocyte chromatin configurations. We showed differences in viscoelastic properties within nucleoplasm of NSN-oocytes, visualized by Hoechst 33342 staining. Also, we demonstrate that in germ cells basic biophysical properties of nucleoplasm can be obtained by using optical trapping without disruption and modification of cellular interior.

scholarly journals Relaxation dynamics of colloidal particles at liquid interfaces

2013 ◽  
Author(s):  
Anna Wang ◽  
David M. Kaz ◽  
Ryan McGorty ◽  
Vinothan N. Manoharan
Keyword(s):  
Colloidal Particles ◽  
Liquid Interfaces ◽  
Relaxation Dynamics
Sign in / Sign up

Export Citation Format

Share Document