بررسی عددی رفتار کرنش سختی سلول‌های بنیادی مزنشیمال بر روی بسترهای الاستیک

نوع مقاله: مقاله مکانیک

نویسندگان

1 دانشجو/دانشگاه تهران

2 هیات علمی/دانشگاه تهران

چکیده

به‌منظور پیش‌بینی دقیق پاسخ سلولی، لازم است که در کنار سایر عوامل، اثر پهن‌شدن سلول روی بستر، به عبارتی دیگر اثر سختی بستر نیز در نظر گرفته شود. هم‌چنین، تنش‌های ایجادشده روی هسته، بر اثر پهن‌شدن سلول، نقش تعیین کننده‌ای را در سرنوشت یک سلول بنیادی ایفا می‌کنند. در این پژوهش، اثر کرنش سختی یک سلول مزنشیمال، در مدلی دو بعدی از سلول، به کمک روش اجزای محدود، با اعمال جابه‌جایی تابع زمان به مرز سیتوپلاسم، بررسی عددی شد. با استفاده از تبدیل شوارتز-کریستوفل، مدلی برای پهن‌شدن سلول روی بستر ارائه شده است که می‌تواند در دست‌یابی به پاسخ دقیق سلولی راه‌گشا باشد. سه مدل مختلف برای این پدیده در نظر گرفته شده است. در مدل اول، با سلول به عنوان ماده‌ای غیرزنده رفتار می‌شود. بدین معنا که خواص مکانیکی آن تحت پهن‌شدن روی بستر ثابت می‌ماند. دو مدل دیگر، کرنش سختی خطی و نمایی، مدل‌های فعال هستند. با مقایسه نتایج این سه مدل با نتایج تجربی، مشخص گردید که فرض غیرفعال بودن سلول پاسخ را از میزان دقیق آن دور می‌سازد و در نظر گرفتن ماهیت زنده سلولی، در دو مدل خطی و نمایی، منجر به شباهت بیشتر نتایج، چه از نظر مقدار تنش و چه از نظر شیب تغییرات، با مشاهدات آزمایشگاهی می‌شود. هم‌چنین، مشاهده شد که با افزایش میزان پهن‌شدن سلول روی بستر، اختلاف مقدار تنش بدست‌آمده برای هسته در مدل‌های فعال با مدل غیرفعال افزایش می‌یابد، به نحوی که تنش پیش‌بینی شده توسط مدل خطی به 3/2 برابر آنچه مدل غیرزنده پیش‌بینی می‌کند، می‌رسد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Investigation of the Strain Stiffening Behavior of Mesenchymal Stem Cells on Elastic Substrates

نویسندگان [English]

  • Esmaeel Rahimpour 1
  • Bahman Vahidi 2
  • Zahra Mollahoseini 1
1 MSc/University of Tehran
2 Assistant Professor/University of Tehran
چکیده [English]

In order to accurately predict the cellular response, it is necessary, along with other factors, to consider the effect of the cell spreading on the substrate. Also, the core tensions, due to the cell spreading, play a crucial role in the fate of a stem cell. Therefore, the exact prediction of these tensions is of particular importance. The effect of the strain stiffening of a mesenchymal cell, in a two-dimensional model, was investigated numerically using finite element method, by exerting a time function displacement, to the cytoplasm boundary. Utilizing Schwartz-Christoffel transformation, a model for cell-spreading was proposed that can be used to achieve accurate cellular responses. Three different models are considered. In the first model, the cell is treated as a non-alive material. That is, the mechanical properties remain constant on the substrate. Two other models, the linear and exponential strain-stiffening, are active models. By comparing the results of these models with the experimental results, it was found that the assumption that the cell is inactive departs the response from the exact amount. Therefore, considering the cell’s living nature, in both linear and exponential models, leads to more similarity of the results, both the tension value and the slope of the variations, with the experimental observations. Furthermore, by increasing the amount of the cell spreading, the difference in the amount of the nucleus stress in active models with the inactive model increases, so that the predicted tension by the linear model reaches 2.3 times that predicted by the non-alive model.

کلیدواژه‌ها [English]

  • cell spreading
  • strain stiffening
  • finite element method
  • stem cell
  • Schwarz-Christoffel
 
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