3D reconstruction of bias effects on porosity, alignment and mesoscale structure in electrospun tubular polycaprolactone

Liu, Y.; Chaparro, Francisco J.; Gray, Z.; Gaumer, Jeremy; Cybyk, Daniel B.; Ross, Liam; Gosser, John; Tian, Ziting; Jia, Yizhen; Dull, T. L.; Yarin, Alexander L.; Lannutti, John J.

doi:10.1016/j.polymer.2021.124120

Cited by 4 publications

(19 citation statements)

References 74 publications

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“…To obtain quantitative information regarding the porosity variations observed under SEM, we sintered these depositions to eliminate internal pores and calculated porosity based on the net shrinkage [19][20][21]…”

Section: Resultsmentioning

confidence: 99%

“…In this context, we reexamined the Sampson model [27] of random fiber network(s) and adapt it to show that these porosity variations can quickly diminish pore size and potential for cell ingression. We also reviewed the effect of electrical bias by applying the same model to results of our previous study [19]. Interestingly, periodic occurrence of cell-impermeable fiber bundles is also observed at 200 RPM.…”

Section: Introductionmentioning

confidence: 92%

“…Scaffolds were prepared following previously-established procedure [19] detailed in the S1 File. Briefly, 5 wt% polycaprolactone (PCL) in hexafluoroisopropanol (HFP) solution was electrospun from a +10 kV charged needle onto ~0.95 cm diameter, -1 kV biased cylindrical rods at 6 mL/h for 22 minutes.…”

Section: Scaffold Preparation and Electron Microscopymentioning

confidence: 99%

“…The principles and design of our metrology system have been reported previously [19][20][21]30]. Briefly, mandrel collectors are scanned by a laser micrometer (TLAser122s, Laserlinc) before and after electrospinning to obtain accurate dimension profiles of the tubular deposits.…”

Section: Laser Metrologymentioning

confidence: 99%

“…In light of this, we recently created a new technique allowing quantitative analysis-for the first time-of porosity within electrospun scaffolds versus both position on collector surface and associated fabrication conditions [19][20][21]. It was observed that porosity was markedly sensitive to even small changes in electrospinning conditions.…”

Section: Introductionmentioning

confidence: 99%

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

Liu

Chaparro²,

Tian

et al. 2023

PLoS ONE

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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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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

Section: Scaffold Preparation and Electron Microscopymentioning

confidence: 99%

Section: Laser Metrologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Liu

Chaparro²,

Tian

et al. 2023

PLoS ONE

Self Cite

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Measurement and Modeling of the Nanofiber Surface Potential during Electrospinning on a Patterned Collector: Toward Directed 3D Microstructuration

Liu

Hébraud

Sutter

et al. 2021

Adv Materials Inter

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Electrospinning allows the fabrication of microstructured mats when the nanofiber is deposited on a patterned collector made of regularly distributed protuberances. Such directed self‐assembling strategy results from the building of an electrostatic template induced by the charged deposited fiber strands suspended between the protuberances which in turn induces a field of attractive and repulsive forces that guide the deposition of the fiber during its landing. However, after a certain time of electrospinning, the microstructuration of the mat is generally subjected to modification and is eventually lost. Here, it is shown that the measurement of the surface potential above the deposited nanofibers is a powerful tool to track the evolution of the fibrous microstructuration during the fabrication. First, the electrospinning above a single and adjustable gap is deeply investigated and a model is proposed to explain the surface potential kinetics as a function of the gap size and the processed polymer solution. Then, the surface potential kinetics are correlated with the evolution of the 3D microstructuration in the case of electrospinning on a micropatterned collector. This original strategy paves the way for the controlled fabrication of 3D microstructured mats dedicated to a wide range of applications.

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Reconstruction of Random Fibrous Porous Material and Numerical Study on Its Transport Properties by Fractal Monte Carlo Method

Wang

et al. 2023

Fractals

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The microstructures and transport properties of fibrous porous material are significant for chemical catalysts, textile engineering, electronic devices, etc. In this paper, a fractal Monte Carlo method (FMCM) is developed to reconstruct the random microstructure of fibrous porous material based on the fractal scaling laws of fiber columns. And, the two-point correlation function of reconstructed fibrous material is calculated, which shows the effectiveness of the FMCM reconstruction. Also, the single-phase fluid flow through the reconstructed random fibrous porous material is simulated by the finite element method. The predicted permeability indicates good agreement with available empirical formulas. It has been found that the effective permeability of fibrous porous material decreases with the increase of fractal dimensions for fiber column. However, the fractal dimension of fiber column width has a greater influence on the effective permeability of fibrous porous material compared with that of fiber column length. The proposed numerical method provides an effective tool to reconstruct the irregular microstructure and understand the complex transport mechanisms of fibrous porous material.

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3D reconstruction of bias effects on porosity, alignment and mesoscale structure in electrospun tubular polycaprolactone

Cited by 4 publications

References 74 publications

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

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

Measurement and Modeling of the Nanofiber Surface Potential during Electrospinning on a Patterned Collector: Toward Directed 3D Microstructuration

Reconstruction of Random Fibrous Porous Material and Numerical Study on Its Transport Properties by Fractal Monte Carlo Method

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