Key issues involved with the use of miniature specimens in the characterization of the mechanical behavior of polymeric biomaterials—A review

Lewis, Gladius

doi:10.1002/jbm.10300

Cited by 9 publications

(5 citation statements)

References 49 publications

(52 reference statements)

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“…The test mimics some of the forces and deformation the horn is subject to when the animal is walking. The PR test has been used to determine the shear and tensile properties of small specimens and results have been found to be correlated to the results of tension tests (Lewis, 2002). When performing the PR test, small areas can be targeted and tested.…”

Section: Discussionmentioning

confidence: 99%

Mechanical properties of the bovine claw horn during lactation

Winkler

Margerison

2012

Journal of Dairy Science

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Claw horn disorders are one of the main causes of lameness in dairy cows globally. This study aimed to develop material testing techniques to assess changes in the mechanical properties of bovine claw horn (BCH) and to compare these mechanical properties with existing methods of assessing claw horn disorders during lactation. Lameness was also measured through locomotion scoring to assess the clinical significance of changes observed in the scoring for lesions. Experiment 1 used 8 claws collected from four 12 to 18 mo old beef heifers, to develop BCH sample storage methods and techniques to test the mechanical properties of BCH (puncture resistance and elastic modulus). The increase in the moisture content of BCH had a significant negative exponential effect on the elastic modulus of the sole and white line claw horn and a linear reduction in the puncture resistance of BCH. Placing BCH samples in sealed plastic bags and storing them either at 2°C or by freezing samples at -22°C did not alter the dry matter content and, consequently, the mechanical properties of the claw horn tissue. In experiment 2, BCH was collected from 36 lactating dairy cows and mechanical properties were tested using puncture resistance. Puncture resistance of the sole area of the claw horn decreased significantly when hemorrhages in the tested area increased. The puncture resistance of the sole and white line areas decreased at d 160 postpartum when the cows exhibited higher lesion scores and was lower in hind claws that had higher lesion scores when compared with the fore claws. The highest puncture resistance was found at 270 d postpartum, when the animals were at pasture. Puncture resistance was found to be an effective technique for assessing the effect of period of lactation and increasing hemorrhage levels on the mechanical properties and structural strength of bovine claw horn. It was found to be a good method of comparing changes and differences in mechanical properties and structural strength of BCH from the sole and white line areas within each claw and differences between claws. White line BCH consistently had significantly lower puncture resistance compared with the sole. Bovine claw horn with greater levels of hemorrhage or lower puncture resistance, or both, may provide less protection and increase the risk of foreign body penetration, trauma, and secondary infection of the corium of the claw.

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Section: Discussionmentioning

confidence: 99%

Mechanical properties of the bovine claw horn during lactation

Winkler

Margerison

2012

Journal of Dairy Science

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“…The 3DF scaffolds response was assessed by dynamic mechanical analysis (DMA) since it allows tailoring of test conditions that can more closely simulate the physiological environment of the specific tissue to repair, and it enables scaffolds viscoelastic characterization [37][38][39][40][41]. By varying fiber diameter, fiber spacing and layer thickness in the internal structure of a scaffold, the mechanical properties change.…”

Section: Introductionmentioning

confidence: 99%

3D fiber-deposited scaffolds for tissue engineering: Influence of pores geometry and architecture on dynamic mechanical properties

2006

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“…In this respect dynamic mechanical analysis (DMA) is valuable to measure the viscoelastic behavior of scaffolds fabricated out of these hydrogels (as these polymers are sometimes called) and allows the tailoring of test conditions in order to simulate the physiological environment of the tissue to be reconstructed. [15][16][17][18][19] Several rapid prototyping techniques offer the possibility of directly fabricating scaffolds with different geometric structures and with different material properties. These scaffolds are built layer by layer through material deposition on a stage via computer-aided design (CAD) models and computer-controlled tooling processes (CAM), either as a molten thermoplast (known as fused deposition modeling techniques) 20,21 or as droplets together with a binding agent (referred to 3D printing techniques).…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional fiber‐deposited PEOT/PBT copolymer scaffolds for tissue engineering: Influence of porosity, molecular network mesh size, and swelling in aqueous media on dynamic mechanical properties

Moroni¹,

Wijn²,

Blitterswijk³

2005

J Biomedical Materials Res

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Among novel scaffold fabrication techniques, 3D fiber deposition (3DF) has recently emerged as a means to fabricate well-defined and custom-made scaffolds for tissue regeneration, with 100% interconnected pores. The mechanical behavior of these constructs is dependent not only on different three-dimensional architectural and geometric features, but also on the intrinsic chemical properties of the material used. These affect the mechanics of the solid material and eventually of 3D porous constructs derived from them. For instance, poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) block copolymers are known to have mechanical properties, depending on the PEOT/PBT weight ratio in block form and on the molecular weight of the initial poly(ethylene glycol) (PEG) blocks. These differences are enhanced even more by their different swelling properties in aqueous media. Therefore, this article examines the influence of copolymer compositions in terms of their swelling on dynamic mechanical properties of solid material and porous 3DF scaffolds. The molecular weight of the starting PEG blocks used in the copolymer synthesis varied from 300 to 1000 g/mol. The PEOT/PBT weight ratio in the blocks used varied from 55/45 to 80/20. This corresponded to an increase of the swelling ratio Q from 1.06 to 2.46, and of the mesh size xi from approximately 9 Angstrom to approximately 47 Angstrom. With increased swelling, dynamic mechanical analysis (DMA) revealed a decrease in elastic response and an increase of viscoelasticity. Thus, by coupling structural and chemical characteristics, the viscoelastic properties of PEOT/PBT 3DF scaffolds may be fine tuned to achieve mechanical requirements for a variety of engineered tissues. Ultimately, the combination of 3DF and DMA may be useful to validate the hypothesis that mimicking the biomechanical behavior of a specific tissue for its optimal replacement is an important issue for at least some tissue-engineering applications.

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Key issues involved with the use of miniature specimens in the characterization of the mechanical behavior of polymeric biomaterials—A review

Cited by 9 publications

References 49 publications

Mechanical properties of the bovine claw horn during lactation

Mechanical properties of the bovine claw horn during lactation

3D fiber-deposited scaffolds for tissue engineering: Influence of pores geometry and architecture on dynamic mechanical properties

Three‐dimensional fiber‐deposited PEOT/PBT copolymer scaffolds for tissue engineering: Influence of porosity, molecular network mesh size, and swelling in aqueous media on dynamic mechanical properties

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