scholarly journals Determination by Relaxation Tests of the Mechanical Properties of Soft Polyacrylamide Gels Made for Mechanobiology Studies

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 629
Author(s):  
Daniel Pérez-Calixto ◽  
Samuel Amat-Shapiro ◽  
Diego Zamarrón-Hernández ◽  
Genaro Vázquez-Victorio ◽  
Pierre-Henri Puech ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Materials Science ◽  
Chemical Properties ◽  
Soft Materials ◽  
Maxwell Model ◽  
Biological Tissues ◽  
Elastic Stiffness ◽  
Critical Signal ◽  
Simple Method

Following the general aim of recapitulating the native mechanical properties of tissues and organs in vitro, the field of materials science and engineering has benefited from recent progress in developing compliant substrates with physical and chemical properties similar to those of biological materials. In particular, in the field of mechanobiology, soft hydrogels can now reproduce the precise range of stiffnesses of healthy and pathological tissues to study the mechanisms behind cell responses to mechanics. However, it was shown that biological tissues are not only elastic but also relax at different timescales. Cells can, indeed, perceive this dissipation and actually need it because it is a critical signal integrated with other signals to define adhesion, spreading and even more complicated functions. The mechanical characterization of hydrogels used in mechanobiology is, however, commonly limited to the elastic stiffness (Young’s modulus) and this value is known to depend greatly on the measurement conditions that are rarely reported in great detail. Here, we report that a simple relaxation test performed under well-defined conditions can provide all the necessary information for characterizing soft materials mechanically, by fitting the dissipation behavior with a generalized Maxwell model (GMM). The simple method was validated using soft polyacrylamide hydrogels and proved to be very useful to readily unveil precise mechanical properties of gels that cells can sense and offer a set of characteristic values that can be compared with what is typically reported from microindentation tests.

scholarly journals Determination by Relaxation Tests of the Mechanical Properties of Soft Polyacrylamide Gels Made for Mechanobiology Studies

2021 ◽  
Author(s):  
Daniel Pérez-Calixto ◽  
Samuel Amat-Shapiro ◽  
Diego Zamarrón-Hernández ◽  
Genaro Vázquez-Victorio ◽  
Pierre-Henri Puech ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Materials Science ◽  
Chemical Properties ◽  
Soft Materials ◽  
Maxwell Model ◽  
Biological Tissues ◽  
Elastic Stiffness ◽  
Critical Signal ◽  
Compliant Substrates

Following the general aim of recapitulating the native mechanical properties of tissues and organs in vitro, the field of materials science and engineering has benefited from recent progress in developing compliant substrates with similar physical and chemical properties. In particular, in the field of mechanobiology, soft hydrogels can now reproduce the precise range of stiffnesses of healthy and pathological tissues to study the mechanisms behind cell response to mechanics. However, it was shown that biological tissues are not only elastic but also relax at different timescales. Cells can indeed perceive and actually need this dissipation because it is a critical signal integrated with other signals to define adhesion, spreading and even more complicated functions. The mechanical definition of hydrogels used in mechanobiology is however commonly limited to the elastic stiffness (Young’s modulus) and this value is known to depend greatly on the measurement conditions that are rarely reported. Here, we report that a simple relaxation test performed under well defined conditions can provide all the necessary information to characterize soft materials mechanically, by fitting the dissipation behavior with a generalized Maxwell model (GMM). The method was validated using soft polyacrylamide hydrogels and proved to be very useful to unveil precise mechanical properties of gels that cells can sense and offer a set of characteristic values that can be compared with what is typically reported from microindentation tests.

scholarly journals Image-based analysis of uniaxial ring test for mechanical characterization of soft materials and biological tissues

Soft Matter ◽  
2019 ◽  
Vol 15 (16) ◽  
pp. 3353-3361 ◽  
Author(s):  
Eline E. van Haaften ◽  
Mark C. van Turnhout ◽  
Nicholas A. Kurniawan
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characterization ◽  
Soft Materials ◽  
Biological Tissues ◽  
Ring Test ◽  
Analysis Approach

We propose a simple image-based analysis approach to accurately estimate the mechanical properties of ring-shaped materials.

Validation of BioDent TDI as a New Clinical Diagnostic Method

2011 ◽  
Vol 275 ◽  
pp. 151-154 ◽  
Author(s):  
Yao Yao Ding ◽  
Tadafumi Adschiri ◽  
Garry A. Williams ◽  
Karen E. Callon ◽  
Maureen Watson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Materials Science ◽  
Biological Tissues ◽  
Standard Diet ◽  
Structural Failure ◽  
Testing Specimen ◽  
Three Point Bending ◽  
Indentation Technique ◽  
Compressive Loads ◽  
Point Bend

Indentation is a mature technique that has been widely used in materials science to investigate the mechanical properties of metals and thin films. The indentation technique provides accurate modulus and hardness values of materials over many length scales and can target specific microstructures within heterogeneous materials. A more traditional engineering approach for mechanical properties is three point bend testing which provides an indication of the general fracture performance of the material. The breaking force and toughness results determined are based on the materials overall structure and composition. However, for both techniques, the testing specimen requires certain degree of process. This study evaluated a new indentation technique, which is able to penetrate biological tissues, apply compressive loads on the bone surface and record the resulting displacement, using wild type rats fed with a standard diet. In this study, both femurs from the same animal were tested followed by the three point bending to reach structural failure. We found a correlation between the two techniques and the properties of the bone in the animal model.

scholarly journals Design and construction of a novel measurement device for mechanical characterization of hydrogels: A case study

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247727
Author(s):  
Shayan Shahab ◽  
Mehran Kasra ◽  
Alireza Dolatshahi-Pirouz
Keyword(s):  
Mechanical Properties ◽  
Shear Modulus ◽  
Magnetic Beads ◽  
Mechanical Characterization ◽  
Collagen Gel ◽  
Biological Tissues ◽  
Elastic Behavior ◽  
Collagen Gels ◽  
Collagen Concentration

Natural biopolymer-based hydrogels especially agarose and collagen gels, considering their biocompatibility with cells and their capacity to mimic biological tissues, have widely been used for in-vitro experiments and tissue engineering applications in recent years; nevertheless their mechanical properties are not always optimal for these purposes. Regarding the importance of the mechanical properties of hydrogels, many mechanical characterization studies have been carried out for such biopolymers. In this work, we have focused on understanding the mechanical role of agarose and collagen concentration on the hydrogel strength and elastic behavior. In this direction, Amirkabir Magnetic Bead Rheometry (AMBR) characterization device equipped with an optimized electromagnet, was designed and constructed for the measurement of hydrogel mechanical properties. The operation of AMBR set-up is based on applying a magnetic field to actuate magnetic beads in contact with the gel surface in order to actuate the gel itself. In simple terms the magnetic beads leads give rise to mechanical shear stress on the gel surface when under magnetic influence and together with the associated bead-gel displacement it is possible to calculate the hydrogel shear modulus. Agarose and Collagen gels with respectively 0.2–0.6 wt % and 0.2–0.5 wt % percent concentrations were prepared for mechanical characterization in terms of their shear modulus. The shear modulus values for the different percent concentrations of the agarose gel were obtained in the range 250–650 Pa, indicating the shear modulus increases by increasing in the agar gel concentration. In addition to this, the values of shear modulus for the collagen gel increase as function of concentration in the range 240–520 Pa in accordance with an approximately linear relationship between collagen concentration and gel strength.

scholarly journals Development of a novel mechanical tester for microfracture analysis

2017 ◽  
Vol 13 (4-2) ◽  
pp. 470-476
Author(s):  
Kheng Lim Goh ◽  
Ye Seng Chen ◽  
Roy Jia Jun Chua ◽  
Tze Chow Fong ◽  
Yu Ker Woh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Testing ◽  
Test Specimen ◽  
Soft Materials ◽  
Biological Tissues ◽  
Test Procedures ◽  
Coir Fibre ◽  
Recent Advancement ◽  
Properties Of Materials ◽  
Microscopic Deformation

The study of the mechanical properties of materials is important in the design and fabrication of any microscale product. Acquiring information such as the fracture toughness, fatigue limits, ultimate tensile and yield strength of these materials would help to determine the reliability of the final product made using the material. Traditionally, these material properties are obtained via mechanical testing on a macroscale tester such as the machines produced by Instron. However, mechanical testing of ‘softer’ materials with a microscopic size is more complicated as the test procedures and equipment have to address concerns such as clamping and alignment of specimen. Recent advancement in micromachining and micro-manufacturing has resulted in the availability of advanced and affordable instrumentation that can be applied to precisely manipulate the materials at microscopic dimensions; this provides the impetus to the development of microscale mechanical testers to study the micro-elasticity and micro-fracture mechanics of soft materials. The focus of this report is on the development of a micromechanical tester that can be used to study micrometer thick biomaterials and biological tissues. The tester can be mounted onto an X-Y stage of an inverted or compound microscope to observe the microscopic deformation and microfracture of the test specimen during testing. Three case studies are presented here to illustrate the performance of the mechanical tester. These studies address the characterisation of the mechanical properties of the flax fibre, oil palm empty fruit bunch fibre and coir fibre in dry and wet states.

scholarly journals Graphene composites with dental and biomedical applicability

2018 ◽  
Vol 9 ◽  
pp. 801-808 ◽  
Author(s):  
Sharali Malik ◽  
Felicite M Ruddock ◽  
Adam H Dowling ◽  
Kevin Byrne ◽  
Wolfgang Schmitt ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Properties ◽  
Simple Method ◽  
High Mechanical Strength ◽  
Layer Graphene ◽  
Low Concentrations ◽  
The Mean ◽  
Strength And Durability ◽  
Few Layer Graphene ◽  
Physical And Chemical

Pure graphene in the form of few-layer graphene (FLG) – 1 to 6 layers – is biocompatible and non-cytotoxic. This makes FLG an ideal material to incorporate into dental polymers to increase their strength and durability. It is well known that graphene has high mechanical strength and has been shown to enhance the mechanical, physical and chemical properties of biomaterials. However, for commercial applicability, methods to produce larger than lab-scale quantities of graphene are required. Here, we present a simple method to make large quantities of FLG starting with commercially available multi-layer graphene (MLG). This FLG material was then used to fabricate graphene dental-polymer composites. The resultant graphene-modified composites show that low concentrations of graphene (ca. 0.2 wt %) lead to enhanced performance improvement in physio-mechanical properties – the mean compressive strength increased by 27% and the mean compressive modulus increased by 22%. Herein we report a new, cheap and simple method to make large quantities of few-layer graphene which was then incorporated into a common dental polymer to fabricate graphene-composites which shows very promising mechanical properties.

A Beam Corrected Estimation of the Frequency Dependent Attenuation of Biological Tissues from Backscattered Ultrasound

1983 ◽  
Vol 5 (2) ◽  
pp. 136-147 ◽  
Author(s):  
M.J.T.M. Cloostermans ◽  
J.M. Thijssen
Keyword(s):  
Attenuation Coefficient ◽  
Focused Ultrasound ◽  
Accurate Method ◽  
Biological Tissues ◽  
Acoustic Attenuation ◽  
Simple Method ◽  
Frequency Dependent ◽  
Ultrasound Energy

A practical and highly accurate method of estimation of the frequency-dependent slope of the acoustic attenuation coefficient, α1, using backscattered ultrasound energy is presented. The influence or the focused ultrasound beam is experimentally measured and a simple method for incorporating the field effects in the estimate of α1 is described. The accuracy of the estimate of α1in vitro which appears to be of the order of 10 percent, demonstrates the feasibility of in vivo applications of the technique.

An experimental study of nonlinear rate-dependent behaviour of skeletal muscle to obtain passive mechanical properties

2020 ◽  
Vol 234 (6) ◽  
pp. 590-602
Author(s):  
Sanaz S Hashemi ◽  
Masoud Asgari ◽  
Akbar Rasoulian
Keyword(s):  
Mechanical Properties ◽  
Skeletal Muscle ◽  
Experimental Study ◽  
Biological Tissues ◽  
Experimental Results ◽  
Three Dimensions ◽  
Nonlinear Behaviour ◽  
Muscle Properties ◽  
Dependent Behaviour

Accurate modelling of biological tissues has been a significant need for analysis of the human body. In this article, a comprehensive in vitro experimental study has been done on the fresh bovine skeletal muscle before the onset of rigour mortis in order to provide an experimental description of passive skeletal muscle properties in three dimensions. Different situations including various deformation modes, different loading rates and loading directions are tested to consider all features of skeletal muscle behaviour. Based on the nonlinear continuum mechanics, a three-dimensional visco-hyperelastic model is introduced which considers all aspects of skeletal muscle’s features such as nonlinear hyperelastic, time-dependent behaviour, anisotropy and quasi-incompressibility. Visco-hyperelastic material constants are obtained for passive behaviour of the muscle based on genetic algorithm optimization method via comparing the theoretical and experimental results. Experiments show that the rate of loading affects the configuration of experimental curves considerably. It could be also concluded that compression–tension asymmetry, as well as anisotropic behaviour, of the muscle is due to fibres orientation. Obtained experimental results help to achieve a better understanding of mechanical properties and nonlinear behaviour of the skeletal muscles.

Poly(glycerol sebacate) – a revolutionary biopolymer

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Israd H. Jaafar ◽  
Sabrina S. Jedlicka ◽  
John P. Coulter
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Cell Culture ◽  
Surface Modification ◽  
Mammalian Cell Culture ◽  
Chemical Properties ◽  
Tunable Mechanical Properties ◽  
And Chemical Properties

Abstract Novel materials possessing physical, mechanical, and chemical properties similar to those found in vivo provide a potential platform for building artificial microenvironments for tissue engineering applications. Poly(glycerol sebacate) is one such material. It has tunable mechanical properties within the range of common tissue, and favorable cell response without surface modification with adhesive ligands, and biodegradability. In this chapter, an overview of the material is presented, focusing on synthesis, characterization, microfabrication, use as a substrate in in vitro mammalian cell culture, and degradation characteristics.

In Vivo Mechanical Characterization of Micro-Specimens Using a Novel Micro-Electro-Mechanical System

2011 ◽  
Author(s):  
Leila Ladani ◽  
Daniel Preston
Keyword(s):  
Mechanical Properties ◽  
Biological Tissues ◽  
Micro Electro Mechanical System ◽  
The Body ◽  
Mechanical Degradation ◽  
Element Analysis ◽  
Rigid Frame

Mechanical probing, stimulation and characterization of tissues are of the most challenging areas of engineering due to limitations of working with bio specimens. Understanding the bio-mechanics of tissues could potentially help to understand mechanical degradation of biological tissues due to disease or change in physiological condition of the body. Biomechanical processes at the microscopic level have become increasingly recognized as an important factor in different biological conditions. In many of these conditions analyzing biomechanics of tissues at microscale in vivo or in vitro will provide invaluable information on microenvironment and physiological parameters that affect the microenvironment and mechanical properties. To address the issue of measuring mechanical properties at microscale, an electroactive-based micro-electromechanical machine is designed. The device is comprised of two electroactive (piezoelectric) micro-elements mounted on a rigid frame. Electrical activation of one of the elements causes it to expand and induce a stress in the intervening micro-specimen. The response of the microspecimen to the stress is measured by the deformation and thereby voltage/resistance induced in the second electro-active element. Figure 1 shows the device design and architecture. Analytical analysis and multiphysics finite element analysis (FEA) are used to prove the concept. A summary of the results are shown in the next sections.

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