Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic?
Echinoderms, such as sea cucumbers, have the remarkable property of changing the stiffness of their dermis according to the surrounding chemical environments. When sea cucumber dermal specimens are constantly strained, stress decays exponentially with time. Such stress relaxation is a hallmark of vi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-11-01
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| Series: | Marine Drugs |
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| Online Access: | https://www.mdpi.com/1660-3397/21/12/610 |
| _version_ | 1797380263026622464 |
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| author | Ettore Barbieri Himadri Shikhar Gupta |
| author_facet | Ettore Barbieri Himadri Shikhar Gupta |
| author_sort | Ettore Barbieri |
| collection | DOAJ |
| description | Echinoderms, such as sea cucumbers, have the remarkable property of changing the stiffness of their dermis according to the surrounding chemical environments. When sea cucumber dermal specimens are constantly strained, stress decays exponentially with time. Such stress relaxation is a hallmark of visco-elastic mechanical behavior. In this paper, in contrast, we attempted to interpret stress relaxation from the chemoelasticity viewpoint. We used a finite element model for the microstructure of the sea cucumber dermis. We varied stiffness over time and framed such changes against the first-order reactions of the interfibrillar matrix. Within this hypothetical scenario, we found that stress relaxation would then occur primarily due to fast crosslink splitting between the chains and a much slower macro-chain scission, with characteristic reaction times compatible with relaxation times measured experimentally. A byproduct of the model is that the concentration of undamaged macro-chains in the softened state is low, less than <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>10</mn><mo>%</mo></mrow></semantics></math></inline-formula>, which tallies with physical intuition. Although this study is far from being conclusive, we believe it opens an alternative route worthy of further investigation. |
| first_indexed | 2024-03-08T20:34:54Z |
| format | Article |
| id | doaj.art-7bbd69394ba9423bb2304041c2ff0d5f |
| institution | Directory Open Access Journal |
| issn | 1660-3397 |
| language | English |
| last_indexed | 2024-03-08T20:34:54Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Marine Drugs |
| spelling | doaj.art-7bbd69394ba9423bb2304041c2ff0d5f2023-12-22T14:22:19ZengMDPI AGMarine Drugs1660-33972023-11-01211261010.3390/md21120610Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic?Ettore Barbieri0Himadri Shikhar Gupta1Center for Mathematical Science and Advanced Technology (MAT), Research Institute for Value-Added-Information Generation (VAiG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama 236-0001, JapanSchool of Engineering and Materials Science (SEMS) & Institute of Bioengineering (IOB), Queen Mary University of London, London E1 4NS, UKEchinoderms, such as sea cucumbers, have the remarkable property of changing the stiffness of their dermis according to the surrounding chemical environments. When sea cucumber dermal specimens are constantly strained, stress decays exponentially with time. Such stress relaxation is a hallmark of visco-elastic mechanical behavior. In this paper, in contrast, we attempted to interpret stress relaxation from the chemoelasticity viewpoint. We used a finite element model for the microstructure of the sea cucumber dermis. We varied stiffness over time and framed such changes against the first-order reactions of the interfibrillar matrix. Within this hypothetical scenario, we found that stress relaxation would then occur primarily due to fast crosslink splitting between the chains and a much slower macro-chain scission, with characteristic reaction times compatible with relaxation times measured experimentally. A byproduct of the model is that the concentration of undamaged macro-chains in the softened state is low, less than <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>10</mn><mo>%</mo></mrow></semantics></math></inline-formula>, which tallies with physical intuition. Although this study is far from being conclusive, we believe it opens an alternative route worthy of further investigation.https://www.mdpi.com/1660-3397/21/12/610chemoelasticitysea cucumberfinite element methodfirst-order reactions |
| spellingShingle | Ettore Barbieri Himadri Shikhar Gupta Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic? Marine Drugs chemoelasticity sea cucumber finite element method first-order reactions |
| title | Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic? |
| title_full | Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic? |
| title_fullStr | Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic? |
| title_full_unstemmed | Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic? |
| title_short | Is Stress Relaxation in Sea Cucumber Dermis Chemoelastic? |
| title_sort | is stress relaxation in sea cucumber dermis chemoelastic |
| topic | chemoelasticity sea cucumber finite element method first-order reactions |
| url | https://www.mdpi.com/1660-3397/21/12/610 |
| work_keys_str_mv | AT ettorebarbieri isstressrelaxationinseacucumberdermischemoelastic AT himadrishikhargupta isstressrelaxationinseacucumberdermischemoelastic |