scholarly journals Plate reader microrheology

2020 ◽  
Author(s):  
Robert F. Hawkins ◽  
Gregg A. Duncan
Keyword(s):  
Particle Tracking ◽  
Fluorescence Polarization ◽  
Rotational Diffusion ◽  
Polymeric Materials ◽  
Soft Materials ◽  
Clinical Samples ◽  
Clinical Settings ◽  
Particle Tracking Microrheology ◽  
Plate Reader ◽  
Potential Applications

AbstractIn this work, we report the development of a simplified microrheological method that can be used to rapidly study soft materials. This approach uses fluorescence polarization and a plate reader format to measure the rotational diffusion of nanoparticles within a sample of interest. We show that this measurement is sensitive to viscosity-dependent changes in polymeric soft materials and is correlated with particle tracking microrheology, a previously validated measure of microrheology. Using these fluorescence polarization-based measurements, we describe formalism that enables reasonable estimation of viscosity in polymeric materials after accounting for length-scale dependent effects of the polymer environment on the nanoparticle rotational diffusion. The use of a plate reader format allows this approach to be higher throughput, less technically challenging, and more widely accessible than standard macro- and microrheological methods, making it available to non-experts. This approach has potential applications in academic and industry settings where conventional rheological equipment may not be available, as well as in clinical settings to rapidly characterize human clinical samples.

scholarly journals Measuring the mechanical properties of apoptotic cells using particle tracking microrheology

2021 ◽  
Author(s):  
Ahmed El Kaffas
Keyword(s):  
Mechanical Properties ◽  
Particle Tracking ◽  
Numerical Models ◽  
Soft Materials ◽  
Point Particle ◽  
High Frequency Ultrasound ◽  
Particle Tracking Microrheology ◽  
Viscous Modulus ◽  
Pc3 Cells ◽  
Frequency Ultrasound

Numerical models developed to study high frequency ultrasound scattering during apoptosis require knowledge of mechanical properties of cells. Particle Tracking Microrheology (PTM) is a technique for studying the mechanical properties of soft materials. By tracking the Brownian movement of particles embedded in a material, its mechanical properties can be extracted. In this thesis, PTM is used to measure the relative changes in the viscoelasticity of apoptotic PC3 cells. PTM was first validated in purely viscous and viscoelastic phantoms. It was found to work well in viscous phantoms, but was limited to only measuring relative changes of the viscoelasticity of viscoelastic materials. After validation, PTM measurements in cells showed that the elastic and viscous modulus increased by over 50 Pa and 20 Pa respectively over the course of the treatment. Preliminary development of another technique known as Two-Point Particle Tracking Microrheology (TPM) is also presented in this thesis.

scholarly journals Measuring the mechanical properties of apoptotic cells using particle tracking microrheology

2021 ◽  
Author(s):  
Ahmed El Kaffas
Keyword(s):  
Mechanical Properties ◽  
Particle Tracking ◽  
Numerical Models ◽  
Soft Materials ◽  
Point Particle ◽  
High Frequency Ultrasound ◽  
Particle Tracking Microrheology ◽  
Viscous Modulus ◽  
Pc3 Cells ◽  
Frequency Ultrasound

Numerical models developed to study high frequency ultrasound scattering during apoptosis require knowledge of mechanical properties of cells. Particle Tracking Microrheology (PTM) is a technique for studying the mechanical properties of soft materials. By tracking the Brownian movement of particles embedded in a material, its mechanical properties can be extracted. In this thesis, PTM is used to measure the relative changes in the viscoelasticity of apoptotic PC3 cells. PTM was first validated in purely viscous and viscoelastic phantoms. It was found to work well in viscous phantoms, but was limited to only measuring relative changes of the viscoelasticity of viscoelastic materials. After validation, PTM measurements in cells showed that the elastic and viscous modulus increased by over 50 Pa and 20 Pa respectively over the course of the treatment. Preliminary development of another technique known as Two-Point Particle Tracking Microrheology (TPM) is also presented in this thesis.

scholarly journals Two-point particle tracking microrheology of nematic complex fluids

Soft Matter ◽  
2016 ◽  
Vol 12 (26) ◽  
pp. 5758-5779 ◽  
Author(s):  
Manuel Gómez-González ◽  
Juan C. del Álamo
Keyword(s):  
Particle Tracking ◽  
Actin Filaments ◽  
Complex Fluids ◽  
Soft Materials ◽  
Point Particle ◽  
Shear Moduli ◽  
Technological Complex ◽  
Particle Tracking Microrheology

Many biological and technological complex fluids exhibit microstructural alignment and nematic rheology. We provide a directional two-pont particle tracking microrheology formulation to measure the directional shear moduli of soft materials. We apply it to study the directional rheology of a solution of aligned F-actin filaments.

Novel organic, polymeric materials for electronics applications

2002 ◽  
Vol 722 ◽  
Author(s):  
Ram W. Sabnis ◽  
Mary J. Spencer ◽  
Douglas J. Guerrero
Keyword(s):  
Optical Density ◽  
Chemical Vapor ◽  
Polymeric Materials ◽  
Substantial Improvement ◽  
Polymeric Systems ◽  
Patterned Wafers ◽  
Visible Spectra ◽  
Potential Applications ◽  
Deep Ultraviolet ◽  
Deposited Films

AbstractNovel organic, polymeric materials and processes of depositing thin films on electronics substrates by chemical vapor deposition (CVD) have been developed and the lithographic behavior of photoresist coated over these CVD films at deep ultraviolet (DUV) wavelength has been evaluated. The specific monomers synthesized for DUV applications include [2.2](1,4)- naphthalenophane, [2.2](9,10)-anthracenophane and their derivatives which showed remarkable film uniformity on flat wafers and conformality over structured topography wafers, upon polymerization by CVD. The chemical, physical and optical properties of the deposited films have been characterized by measuring parameters such as thickness uniformity, solubility, conformality, adhesion to semiconductor substrates, ultraviolet-visible spectra, optical density, optical constants, defectivity, and resist compatibility. Scanning electron microscope (SEM) photos of cross-sectioned patterned wafers showed verticle profiles with no footing, standing waves or undercut. Resist profiles down to 0.10 νm dense lines and 0.09 νm isolated lines were achieved in initial tests. CVD coatings generated 96-100% conformal films, which is a substantial improvement over commercial spin-on polymeric systems. The light absorbing layers have high optical density at 248 nm and are therefore capable materials for DUV lithography applications. CVD is a potentially useful technology to extend lithography for sub-0.15 νm devices. These films have potential applications in microelectronics, optoelectronics and photonics.

Multiple particle tracking

2018 ◽  
Author(s):  
Eric M. Furst ◽  
Todd M. Squires
Keyword(s):  
Brownian Motion ◽  
Best Practices ◽  
Particle Tracking ◽  
Heterogeneous Material ◽  
Quantitative Measurements ◽  
Particle Tracking Microrheology ◽  
Shell Models ◽  
Multiple Particle Tracking ◽  
Microscopy Data ◽  
Multiple Particle

The fundamentals and best practices of multiple particle tracking microrheology are discussed, including methods for producing video microscopy data, analyzing data to obtain mean-squared displacements and displacement correlations, and, critically, the accuracy and errors (static and dynamic) associated with particle tracking. Applications presented include two-point microrheology, methods for characterizing heterogeneous material rheology, and shell models of local (non-continuum) heterogeneity. Particle tracking has a long history. The earliest descriptions of Brownian motion relied on precise observations, and later quantitative measurements, using light microscopy.

scholarly journals Study of Physical and Degradation Properties of 3D-Printed Biodegradable, Photocurable Copolymers, PGSA-co-PEGDA and PGSA-co-PCLDA

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1263 ◽  
Author(s):  
June-Yo Chen ◽  
Joanne Hwang ◽  
Wai-Sam Ao-Ieong ◽  
Yung-Che Lin ◽  
Yi-Kong Hsieh ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Weight Ratio ◽  
Polymeric Materials ◽  
Pure Substance ◽  
Digital Light Processing ◽  
Glycol Diacrylate ◽  
Young’S Moduli ◽  
Potential Applications ◽  
Degradation Properties

As acrylated polymers become more widely used in additive manufacturing, their potential applications toward biomedicine also raise the demand for biodegradable, photocurable polymeric materials. Polycaprolactone diacrylate (PCLDA) and poly(ethylene glycol) diacrylate (PEGDA) are two popular choices of materials for stereolithography (SLA) and digital light processing additive manufacturing (DLP-AM), and have been applied to many biomedical related research. However, both materials are known to degrade at a relatively low rate in vivo, limiting their applications in biomedical engineering. In this work, biodegradable, photocurable copolymers are introduced by copolymerizing PCLDA and/or PEGDA with poly(glycerol sebacate) acrylate (PGSA) to form a network polymer. Two main factors are discussed: the effect of degree of acrylation in PGSA and the weight ratio between the prepolymers toward the mechanical and degradation properties. It is found that by blending prepolymers with various degree of acrylation and at various weight ratios, the viscosity of the prepolymers remains stable, and are even more 3D printable than pure substances. The formation of various copolymers yielded a database with selectable Young’s moduli between 0.67–10.54 MPa, and the overall degradation rate was significantly higher than pure substance. In addition, it is shown that copolymers fabricated by DLP-AM fabrication presents higher mechanical strength than those fabricated via direct UV exposure. With the tunable mechanical and degradation properties, the photocurable, biodegradable copolymers are expected to enable a wider application of additive manufacturing toward tissue engineering.

Novel Behavior in Smart Polymeric Materials: Stress Memory and its Potential Applications

2016 ◽  
Vol 97 ◽  
pp. 93-99
Author(s):  
Jin Lian Hu ◽  
Harishkumar Narayana
Keyword(s):  
Magnetic Field ◽  
Shape Memory ◽  
Smart Materials ◽  
Shape Memory Polymers ◽  
Polymeric Materials ◽  
External Stimulus ◽  
Artificial Muscles ◽  
Recovery Stress ◽  
Stress Memory ◽  
Potential Applications

Materials, structures and systems, responsive to an external stimulus are smart and adaptive to our human demands. Among smart materials, polymers with shape memory effect are at the forefront of research leading to comprehensive publications and wide applications. In this paper, we extend the concept of shape memory polymers to stress memory ones, which have been discovered recently. Like shape memory, stress memory represents a phenomenon where the stress in a polymer can be programmed, stored and retrieved reversibly with an external stimulus such as temperature and magnetic field. Stress memory may be mistaken as the recovery stress which was studied quite broadly. Our further investigation also reveals that stress memory is quite different from recovery stress containing multi-components including elastic and viscoelastic forces in addition to possible memory stress. Stress memory could be used into applications such as sensors, pressure garments, massage devices, electronic skins and artificial muscles. The current revelation of stress memory potentials is emanated from an authentic application of memory fibres, films, and foams in the smart compression devices for the management of chronic and therapeutic disorders.

scholarly journals The Face of Hypervirulent Klebsiella Pneumoniae (hvKp) Isolated from Clinical Samples of Two Iranian Teaching Hospitals

2021 ◽  
Author(s):  
Rahimeh Sanikhani ◽  
Mohammad Moeinirad ◽  
Hamid Solgi ◽  
Azar Haddadi ◽  
Fereshteh Shahcheraghi ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Klebsiella Pneumoniae ◽  
Multidrug Resistant ◽  
Teaching Hospitals ◽  
Clinical Samples ◽  
Clinical Settings ◽  
Urgent Problem ◽  
Clonal Relatedness ◽  
The Face ◽  
Global Concern

Abstract Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a pathogen of global concern. In this study, both phenotypic and genotypic tests were used to detect hvKp. Antimicrobial resistance profiles and clonal relatedness of clinical isolates were also determined. We found that 62.6% of the isolates were tellurite resistant and among them iucA or iutA or peg344 as hvKp molecular markers, were positive. The blaSHV (81.4%), followed by blaCTX−M15 (75.5%) and blaTEM (67.6%), blaOXA−48 (33.7%), blaNDM−1 (32.3%) were detected, while blaKPC−1 was not present in any hvKp isolates. It was found that the majority of hvKp isolates belonged to capsular serotype K20 and ompK36 group C, which is related to CG23 (e.g. ST23). A high percentage of multidrug-resistant hvKp (MDR-hvKp) and high resistance to imipenem (66%) indicated that there is an urgent problem that should be addressed in the clinical settings.

scholarly journals Particle tracking microrheology of purified gastrointestinal mucins

Biopolymers ◽  
2014 ◽  
Vol 101 (4) ◽  
pp. 366-377 ◽  
Author(s):  
Pantelis Georgiades ◽  
Paul D. A. Pudney ◽  
David J. Thornton ◽  
Thomas A. Waigh
Keyword(s):  
Particle Tracking ◽  
Particle Tracking Microrheology
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