Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows

Hydrogels have been used as scaffolds and structural supports for cell growth. However, injecting these hydrogels requires substantial forces which also lead to high shear in the cell and ultimately cell death. Current methods to mitigate this problem suffer from limited applicability, poor durabili...

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Main Author: Dhulipala, Somayajulu
Other Authors: Varanasi, Kripa K.
Format: Thesis
Published: Massachusetts Institute of Technology 2022
Online Access:https://hdl.handle.net/1721.1/138941
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author Dhulipala, Somayajulu
author2 Varanasi, Kripa K.
author_facet Varanasi, Kripa K.
Dhulipala, Somayajulu
author_sort Dhulipala, Somayajulu
collection MIT
description Hydrogels have been used as scaffolds and structural supports for cell growth. However, injecting these hydrogels requires substantial forces which also lead to high shear in the cell and ultimately cell death. Current methods to mitigate this problem suffer from limited applicability, poor durability, lack of stability and no significant enhancement in injectability. Here, we propose a viscoplastic lubricated gel co-flow, where the flow of the cell-laden payload through needles is facilitated by coaxial lubrication from a lower yield stress gel, to mitigate shear death, enhance injectability and enable stable flow. In this study, we optimize fluidic and flow parameters to minimize drag and shear on the payload gel. We establish regime maps of stable coaxial lubrication using both simulations and experiments. The velocity profile inside the needle is plotted using PTV to visualize the shear-free transport of the inner payload. Experimentally, we were able to achieve a 4x reduction in injection force and 5x increase in plug region (zero-shear region). Finally, we propose a theoretical model to explain the simulations and experimental results.
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spelling mit-1721.1/1389412022-01-15T03:14:33Z Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows Dhulipala, Somayajulu Varanasi, Kripa K. Massachusetts Institute of Technology. Department of Mechanical Engineering Hydrogels have been used as scaffolds and structural supports for cell growth. However, injecting these hydrogels requires substantial forces which also lead to high shear in the cell and ultimately cell death. Current methods to mitigate this problem suffer from limited applicability, poor durability, lack of stability and no significant enhancement in injectability. Here, we propose a viscoplastic lubricated gel co-flow, where the flow of the cell-laden payload through needles is facilitated by coaxial lubrication from a lower yield stress gel, to mitigate shear death, enhance injectability and enable stable flow. In this study, we optimize fluidic and flow parameters to minimize drag and shear on the payload gel. We establish regime maps of stable coaxial lubrication using both simulations and experiments. The velocity profile inside the needle is plotted using PTV to visualize the shear-free transport of the inner payload. Experimentally, we were able to achieve a 4x reduction in injection force and 5x increase in plug region (zero-shear region). Finally, we propose a theoretical model to explain the simulations and experimental results. S.M. 2022-01-14T14:39:47Z 2022-01-14T14:39:47Z 2021-06 2021-06-30T15:16:10.545Z Thesis https://hdl.handle.net/1721.1/138941 0000-0002-3144-8583 In Copyright - Educational Use Permitted Copyright MIT http://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology
spellingShingle Dhulipala, Somayajulu
Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows
title Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows
title_full Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows
title_fullStr Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows
title_full_unstemmed Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows
title_short Enhancing Injectability and Viability of Cells using Viscoplastic Lubricated Flows
title_sort enhancing injectability and viability of cells using viscoplastic lubricated flows
url https://hdl.handle.net/1721.1/138941
work_keys_str_mv AT dhulipalasomayajulu enhancinginjectabilityandviabilityofcellsusingviscoplasticlubricatedflows