scholarly journals Collagen networks determine viscoelastic properties of connective tissues yet do not hinder diffusion of the aqueous solvent

Soft Matter ◽  
2019 ◽  
Vol 15 (14) ◽  
pp. 3055-3064 ◽  
Author(s):  
Frank Sauer ◽  
Linda Oswald ◽  
Angela Ariza de Schellenberger ◽  
Heiko Tzschätzsch ◽  
Felix Schrank ◽  
...  
Keyword(s):  
Power Law ◽  
Viscoelastic Properties ◽  
Collagen Gels ◽  
Connective Tissues ◽  
Aqueous Solvent

Novel tabletop MRE reveals loss of viscoelastic power law behavior in structurally unchanged collagen gels after intrafibrillar crosslinking.

Advances Toward Forming Synthetic Mimetic Tendon

MRS Advances ◽  
2016 ◽  
Vol 1 (18) ◽  
pp. 1283-1288
Author(s):  
Dilinazi Aishanjiang ◽  
Emily C. Green ◽  
Heng Li ◽  
Marilyn L. Minus
Keyword(s):  
Type I Collagen ◽  
Fibrillar Structure ◽  
Type I ◽  
Structural Development ◽  
Collagen Gels ◽  
Connective Tissues ◽  
Synthetic Fibers ◽  
Spinning Process ◽  
Bovine Type

ABSTRACTCollagen is the most abundant protein present in the human body and found in connective tissues, bone, and tendon. It is also known as a natural resource for healing damaged skin tissues [1]. In this study, under specific microenvironment conditions, mimetic collagen gels were successfully formed synthetically from reconstituted Bovine type I collagen monomers. This was achieved by controlling ionic strength, temperature and pH, allowing fibrils with native mimetic D periodic banding structure to assemble spontaneously within the gels. In addition, by providing appropriate aging temperatures and times, mature collagen fibril growth is also realized in the gels in vitro. Mimetic gels were subsequently formed into fibers through a wet-spinning process. These spun fibers were found to preserve the native mimetic D periodic banding and fibrillar structure formed in the initial gels. As a result, the synthetic fibers resemble native tendon. Here structural development within the gel samples and fibers as a function of processing was analyzed by scanning electron microscopy (SEM). Results in this study also show a potentially new route for the fabrication of synthetic collagen fibers mimicking tendon, which may find applications as engineered tissues or scaffolding materials.

scholarly journals On the time-temperature equivalency in green wood: Characterisation of viscoelastic properties in longitudinal direction

Holzforschung ◽  
2009 ◽  
Vol 63 (3) ◽  
Author(s):  
Jana Dlouhá ◽  
Bruno Clair ◽  
Olivier Arnould ◽  
Petr Horáček ◽  
Joseph Gril
Keyword(s):  
Power Law ◽  
Viscoelastic Properties ◽  
Creep Behaviour ◽  
Longitudinal Direction ◽  
Temperature Dependency ◽  
Arrhenius Law ◽  
Degree Polynomial ◽  
Creep Tests ◽  
Softening Effect ◽  
Green Wood

Abstract Aiming at modelling tree mechanics, viscoelastic properties of green wood along fibres was investigated through a sequence of creep tests in the temperature range of 30°C–70°C. The apparent validity of time-temperature equivalency was questioned by discrepancies evidenced in the approximated complex plane (ACP). This paradox was solved by assuming that the temperature not only accelerates the viscoelastic processes but also slightly increases their intensity. This softening effect of the temperature on the compliance was described by a 2nd degree polynomial. Time-temperature dependency fitted very well to the Arrhenius law up to 60°C. Based on the ACP, the power law was proposed for modelling creep behaviour in green wood. The method was successfully used for all specimens investigated.

scholarly journals Imaging viscoelastic properties of live cells by AFM: power-law rheology on the nanoscale

Soft Matter ◽  
2015 ◽  
Vol 11 (23) ◽  
pp. 4584-4591 ◽  
Author(s):  
Fabian M. Hecht ◽  
Johannes Rheinlaender ◽  
Nicolas Schierbaum ◽  
Wolfgang H. Goldmann ◽  
Ben Fabry ◽  
...  
Keyword(s):  
Power Law ◽  
Viscoelastic Properties ◽  
Live Cells

Viscoelastic Properties of Spine Ligament Collagen Fascicles

2008 ◽  
Author(s):  
Scott R. Lucas ◽  
Robert S. Salzar ◽  
Cameron R. Bass
Keyword(s):  
Viscoelastic Properties ◽  
Volume Fraction ◽  
Material Model ◽  
Ground Substance ◽  
Connective Tissues ◽  
Model Based

Connective tissues, such as ligaments and tendons, are comprised of varying amounts of collagen, elastin, and ground substance. It is conceivable to develop a microstructural material model based on the volume fraction and orientation of each constituent, and their interactions.

scholarly journals Effects of a Pseudophysiological Environment on the Elastic and Viscoelastic Properties of Collagen Gels

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sébastien Meghezi ◽  
Frédéric Couet ◽  
Pascale Chevallier ◽  
Diego Mantovani
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Viscoelastic Properties ◽  
Saline Solution ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Tensile Tests ◽  
Biological Properties ◽  
Vascular Tissue Engineering ◽  
Collagen Gels

Vascular tissue engineering focuses on the replacement of diseased small-diameter blood vessels with a diameter less than 6 mm for which adequate substitutes still do not exist. One approach to vascular tissue engineering is to culture vascular cells on a scaffold in a bioreactor. The bioreactor establishes pseudophysiological conditions for culture (medium culture, 37°C, mechanical stimulation). Collagen gels are widely used as scaffolds for tissue regeneration due to their biological properties; however, they exhibit low mechanical properties. Mechanical characterization of these scaffolds requires establishing the conditions of testing in regard to the conditions set in the bioreactor. The effects of different parameters used during mechanical testing on the collagen gels were evaluated in terms of mechanical and viscoelastic properties. Thus, a factorial experiment was adopted, and three relevant factors were considered: temperature (23°C or 37°C), hydration (aqueous saline solution or air), and mechanical preconditioning (with or without). Statistical analyses showed significant effects of these factors on the mechanical properties which were assessed by tensile tests as well as stress relaxation tests. The last tests provide a more consistent understanding of the gels' viscoelastic properties. Therefore, performing mechanical analyses on hydrogels requires setting an adequate environment in terms of temperature and aqueous saline solution as well as choosing the adequate test.

scholarly journals Differences in Viscoelasticity of Ophthalmic Polymer Solution after Sterilization

2020 ◽  
Vol 17 (7) ◽  
pp. 686-697
Author(s):  
Yotsanan WEERAPOL ◽  
Pornsak SRIAMORNSAK
Keyword(s):  
Polymer Solution ◽  
Power Law ◽  
Viscoelastic Properties ◽  
Membrane Filtration ◽  
Loss Modulus ◽  
Methyl Cellulose ◽  
Ophthalmic Solution ◽  
Solution Viscosity ◽  
Steam Sterilization ◽  
Power Law Index

Polymer solution has been used for increasing viscosity of ophthalmic solution in order to prolong the retention of active drug in the eye. The ophthalmic solution must be sterilized, which may affect the rheology properties of viscosity-inducing polymers. The aim of this study was to investigate the effect of sterilization treatment on viscosity-inducing agents (i.e., poloxamer, polyvinyl alcohol; (PVA), methyl cellulose (MC), polyvinylpyrrolidone (PVP) and carbomer). The effect of membrane filtration and steam sterilization or autoclaving (121 °C, 15 Ib/inch2, 15 min) were determined. A rheometer was used to investigate the viscosity and viscoelastic properties between treated and untreated polymer solutions. The power law model, consistency index (k), and power law index (n) of polymer solution viscosity were compared. For viscoelastic properties, storage modulus and loss modulus were examined. The results demonstrated that, viscosity of carbomer and MC solution (1 and 2 %) were changed after steam sterilization. No difference in viscosity was observed for PVP, PVA and poloxamer solution, between untreated and treated samples. The storage and loss moduli of PVA solution after autoclaving were not different when comparing with the untreated polymer solution. From this study, it could be concluded that the sterilization treatment influenced the viscosity behavior and viscoelastic properties of polymer solution used as viscosity-inducing agent in ophthalmic solution. Therefore, the selection of polymer and sterilization method should be carefully considered.

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