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Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology

We applied a recently developed method, laser metrology, to characterize the influence of collector rotation on porosity gradients of electrospun polycaprolactone (PCL) widely investigated for use in tissue engineering. The prior- and post-sintering dimensions of PCL scaffolds were compared to deriv...

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Autores principales: Liu, Yi-xiao, Chaparro, Francisco J., Tian, Ziting, Jia, Yizhen, Gosser, John, Gaumer, Jeremy, Ross, Liam, Tafreshi, Hooman, Lannutti, John J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9997878/
https://www.ncbi.nlm.nih.gov/pubmed/36893193
http://dx.doi.org/10.1371/journal.pone.0282903
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author Liu, Yi-xiao
Chaparro, Francisco J.
Tian, Ziting
Jia, Yizhen
Gosser, John
Gaumer, Jeremy
Ross, Liam
Tafreshi, Hooman
Lannutti, John J.
author_facet Liu, Yi-xiao
Chaparro, Francisco J.
Tian, Ziting
Jia, Yizhen
Gosser, John
Gaumer, Jeremy
Ross, Liam
Tafreshi, Hooman
Lannutti, John J.
author_sort Liu, Yi-xiao
collection PubMed
description We applied a recently developed method, laser metrology, to characterize the influence of collector rotation on porosity gradients of electrospun polycaprolactone (PCL) widely investigated for use in tissue engineering. The prior- and post-sintering dimensions of PCL scaffolds were compared to derive quantitative, spatially-resolved porosity ‘maps’ from net shrinkage. Deposited on a rotating mandrel (200 RPM), the central region of deposition reaches the highest porosity, ~92%, surrounded by approximately symmetrical decreases to ~89% at the edges. At 1100 RPM, a uniform porosity of ~88–89% is observed. At 2000 RPM, the lowest porosity, ~87%, is found in the middle of the deposition, rebounding to ~89% at the edges. Using a statistical model of random fiber network, we demonstrated that these relatively small changes in porosity values produce disproportionately large variations in pore size. The model predicts an exponential dependence of pore size on porosity when the scaffold is highly porous (e.g., >80%) and, accordingly, the observed porosity variation is associated with dramatic changes in pore size and ability to accommodate cell infiltration. Within the thickest regions most likely to ‘bottleneck’ cell infiltration, pore size decreases from ~37 to 23 μm (38%) when rotational speeds increased from 200 to 2000 RPM. This trend is corroborated by electron microscopy. While faster rotational speeds ultimately overcome axial alignment induced by cylindrical electric fields associated with the collector geometry, it does so at the cost of eliminating larger pores favoring cell infiltration. This puts the bio-mechanical advantages associated with collector rotation-induced alignment at odds with biological goals. A more significant decrease in pore size from ~54 to ~19 μm (65%), well below the minimum associated with cellular infiltration, is observed from enhanced collector biases. Finally, similar predictions show that sacrificial fiber approaches are inefficient in achieving cell-permissive pore sizes.
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spelling pubmed-99978782023-03-10 Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology Liu, Yi-xiao Chaparro, Francisco J. Tian, Ziting Jia, Yizhen Gosser, John Gaumer, Jeremy Ross, Liam Tafreshi, Hooman Lannutti, John J. PLoS One Research Article We applied a recently developed method, laser metrology, to characterize the influence of collector rotation on porosity gradients of electrospun polycaprolactone (PCL) widely investigated for use in tissue engineering. The prior- and post-sintering dimensions of PCL scaffolds were compared to derive quantitative, spatially-resolved porosity ‘maps’ from net shrinkage. Deposited on a rotating mandrel (200 RPM), the central region of deposition reaches the highest porosity, ~92%, surrounded by approximately symmetrical decreases to ~89% at the edges. At 1100 RPM, a uniform porosity of ~88–89% is observed. At 2000 RPM, the lowest porosity, ~87%, is found in the middle of the deposition, rebounding to ~89% at the edges. Using a statistical model of random fiber network, we demonstrated that these relatively small changes in porosity values produce disproportionately large variations in pore size. The model predicts an exponential dependence of pore size on porosity when the scaffold is highly porous (e.g., >80%) and, accordingly, the observed porosity variation is associated with dramatic changes in pore size and ability to accommodate cell infiltration. Within the thickest regions most likely to ‘bottleneck’ cell infiltration, pore size decreases from ~37 to 23 μm (38%) when rotational speeds increased from 200 to 2000 RPM. This trend is corroborated by electron microscopy. While faster rotational speeds ultimately overcome axial alignment induced by cylindrical electric fields associated with the collector geometry, it does so at the cost of eliminating larger pores favoring cell infiltration. This puts the bio-mechanical advantages associated with collector rotation-induced alignment at odds with biological goals. A more significant decrease in pore size from ~54 to ~19 μm (65%), well below the minimum associated with cellular infiltration, is observed from enhanced collector biases. Finally, similar predictions show that sacrificial fiber approaches are inefficient in achieving cell-permissive pore sizes. Public Library of Science 2023-03-09 /pmc/articles/PMC9997878/ /pubmed/36893193 http://dx.doi.org/10.1371/journal.pone.0282903 Text en © 2023 Liu et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Liu, Yi-xiao
Chaparro, Francisco J.
Tian, Ziting
Jia, Yizhen
Gosser, John
Gaumer, Jeremy
Ross, Liam
Tafreshi, Hooman
Lannutti, John J.
Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology
title Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology
title_full Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology
title_fullStr Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology
title_full_unstemmed Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology
title_short Visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology
title_sort visualization of porosity and pore size gradients in electrospun scaffolds using laser metrology
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9997878/
https://www.ncbi.nlm.nih.gov/pubmed/36893193
http://dx.doi.org/10.1371/journal.pone.0282903
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