Biofidelic human brain tissue surrogates

Chanda, Arnab; Callaway, Christian; Clifton, Cassie; Unnikrishnan, Vinu

doi:10.1080/15376494.2016.1143749

Cited by 58 publications

(42 citation statements)

References 38 publications

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“…The stress versus strain plots generated from the tests were checked for repeatability ( Figure 2.23 A) and also compared with literature [8] to ensure that there are no machine calibration errors.…”

Section: Preparation Of Matrix and Fiber Materialsmentioning

confidence: 99%

“…For each of the tests, the load (Newtons) versus extension (mm) graphs were plotted and postprocessed to obtain stress versus stretch plots, which were used for further analyses. It should be mentioned here that silicones simulating skin tissues typically exhibit a high cut-out or breaking strengths in the range of [15][16][17][18][19][20][21][22][23][24][25]154,156], while other tissues such as pelvic tissues (Ultimate tensile strength of 1-6 MPa) [7,9,144,157] and brain tissues (Ultimate tensile strength of 300-900 kPa) [1,158,159] may have lower cut-out strengths. Sutures on the other hand have extremely high cut-out strengths in the range of 100-500 MPa [95].…”

Section: Uniaxial Mechanical Testingmentioning

confidence: 99%

“…Combined effects of FVF and fiber orientation on low stretch modulus values of soft composite materials Comparison of the range of soft composite material properties with that of the human skin[2], pelvic[7] and brain tissues[8] …”

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confidence: 99%

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Biofidelic soft composites–experimental and computational modeling

Chanda¹

2018

Preprint

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Biofidelic soft composites or tissues form the building blocks of the human body. Understanding the complex mechanics of these soft composites is the key to understanding the genesis and progression of disease. Biomechanically, soft composites exhibit anisotropic mechanical behavior and comprise of multiple fiber layers within a soft matrix. To date, there is a lack of understanding of the anisotropic mechanical behavior of soft composites, primarily due to unavailability of a robust characterization framework. In this dissertation, novel multiscale computational and experimental investigation models are developed to simulate and characterize anisotropic soft composite mechanical behavior. Soft composite surrogates were first developed to simulate various tissues in the human body namely the skin, brain, artery and vaginal tissues. Novel anisotropic soft composite models were also fabricated taking into consideration the tissue anisotropy and multifunctional properties. Hyperelastic anisotropic constitutive relationships were formulated to precisely characterize the mechanical behavior of soft composite considering varying fiber and matrix contributions, fiber-matrix interactions, fiber orientations and multiple fiber layers. Coupled with high fidelity experimental and computational models, microscopy, and Digital Image Correlation (DIC) studies, the damage and repair of soft composite surrogates are also discussed in this dissertation, with relevance to soft tissue wounds and suture. Computational modeling to understand the interaction between multiple soft composite systems and its effect on soft composite damage are also highlighted in this work. Some specific soft composite interaction systems modeled were the female pelvic system under abdominal loads, whole body impact due to blast, and ulceration in diabetic foot. This dissertation lays the foundation for micro and macro scale anisotropic soft composite modeling and characterization using high fidelity experimental and numerical techniques which will be indispensable for studying tissue mechanics and other soft composite applications in engineering and medicine.

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Section: Preparation Of Matrix and Fiber Materialsmentioning

confidence: 99%

Section: Uniaxial Mechanical Testingmentioning

confidence: 99%

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Biofidelic soft composites–experimental and computational modeling

Chanda¹

2018

Preprint

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“…Soft tissues, polymers and rubbers exhibit a non-linear stress versus strain response which can be characterized using hyperelastic constitutive material models such as Fung, Mooney-Rivlin, Yeoh, Veronda-Westmann, and Humphrey [10,12,13,[16][17][18][19][20][21][22][23]. Hyperelastic curve fit models are based on the definition of the strain-energy function (denoted as Ψ), which depends on the type of material [24,25].…”

Section: Non-linear Materials Modelingmentioning

confidence: 99%

Biofidelic Conductive Synthetic Skin Composites

Chanda¹

2018

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Skin is the first point of contact of the human body with the outer environment, and influences the biomechanics of different organ systems in normal and diseased states. Wearable electronics such as fitness tracking equipment, motion sensing devices, and advanced wearables in prosthetics and orthotics are often used to quantify the interaction of the body with the environment during different physical activities, and improve health. These wearable equipment can be bulky and a source of discomfort to the human skin with prolonged wear. To date, very few flexible polymers have been developed which can conduct electricity and be used in wearable devices. In the current work, a novel conductive synthetic skin composite system was developed, which would be indispensable for integration into wearable technologies, and also allow the biomechanical testing of the human skin for different engineering and medical applications. The mechanical behavior of this polymer can be tuned to mimic the human skin from different locations of the body with varying stiffnesses, with a phenomenal degree of accuracy. The composite system is composed of short carbon fibers dispersed in a multi part silicone based matrix material. The volume fraction of the fibers were varied to control the mechanical and electrical properties of the composite. Uniaxial tensile tests were conducted to generate stress versus strain responses of the synthetic skin composites at different fiber volume fractions, and electrical measurements were recorded at different strains. Microscopy was used to understand composite fiber orientations in unstretched and stretched states, and its effects on the electrical conductivity of the material. Additionally, non-linear material characterization models were developed to characterize the composite variants. To the best of our knowledge, such an accurate synthetic skin composite system with tailorable electrical properties has not been developed; making this state of the art in bio mimicking and functionalization of the human skin.

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“…Two-part silicone material with a shore hardness of 30A (Mold Star 30 from Smooth-On, Inc., Macungie, PA, USA) was mixed in a 1:1 ratio by weight to fabricate biofidelic human skin phantoms [19,[24][25][26][27][28][29][30][31]. Ten test coupons were generated with 50 mm length, 9 mm width and 2.5 mm depth.…”

Section: Test Specimen Fabrication and Digital Image Correlation (Dicmentioning

confidence: 99%

Biomechanical Modeling of Wounded Skin

Chanda

Upchurch

2018

J. Compos. Sci.

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Skin injury is the most common type of injury, which manifests itself in the form of wounds and cuts. A minor wound repairs itself within a short span of time. However, deep wounds require adequate care and sometime clinical interventions such as surgical suturing for their timely closure and healing. In literature, mechanical properties of skin and other tissues are well known. However, the anisotropic behavior of wounded skin has not been studied yet, specifically with respect to localized overstraining and possibilities of rupture. In the current work, the biomechanics of common skin wound geometries were studied with a biofidelic skin phantom, using uniaxial mechanical testing and Digital Image Correlation (DIC). Global and local mechanical properties were investigated, and possibilities of rupture due to localized overstraining were studied across different wound geometries and locations. Based on the experiments, a finite element (FE) model was developed for a common elliptical skin wound geometry. The fidelity of this FE model was evaluated with simulation of uniaxial tension tests. The induced strain distributions and stress-stretch responses of the FE model correlated very well with the experiments (R2 > 0.95). This model would be useful for prediction of the mechanical response of common wound geometries, especially with respect to their chances of rupture due to localized overstraining. This knowledge would be indispensable for pre-surgical planning, and also in robotic surgeries, for selection of appropriate wound closure techniques, which do not overstrain the skin tissue or initiate tearing.

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Biofidelic human brain tissue surrogates

Cited by 58 publications

References 38 publications

Biofidelic soft composites–experimental and computational modeling

Biofidelic soft composites–experimental and computational modeling

Biofidelic Conductive Synthetic Skin Composites

Biomechanical Modeling of Wounded Skin

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