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Bista P, Ratschow AD, Stetten AZ, Butt HJ, Weber SAL. Surface charge density and induced currents by self-charging sliding drops. Soft Matter 2024. [PMID: 38639086 DOI: 10.1039/d4sm00205a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Spontaneous charge separation in drops sliding over a hydrophobized insulator surface is a well-known phenomenon and lots of efforts have been made to utilize this effect for energy harvesting. For maximizing the efficiency of such devices, a comprehensive understanding of the dewetted surface charge would be required to quantitatively predict the electric current signals, in particular for drop sequences. Here, we use a method based on mirror charge detection to locally measure the surface charge density after drops move over a hydrophobic surface. For this purpose, we position a metal electrode beneath the hydrophobic substrate to measure the capacitive current induced by the moving drop. Furthermore, we investigate drop-induced charging on different dielectric surfaces together with the surface neutralization processes. The surface neutralizes over a characteristic time, which is influenced by the substrate and the surrounding environment. We present an analytical model that describes the slide electrification using measurable parameters such as the surface charge density and its neutralization time. Understanding the model parameters and refining them will enable a targeted optimization of the efficiency in solid-liquid charge separation.
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Affiliation(s)
- Pravash Bista
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Aaron D Ratschow
- Institute for Nano- and Microfluidics, TU Darmstadt, Peter-Grünberg-Str. 10, 64289 Darmstadt, Germany
| | - Amy Z Stetten
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Stefan A L Weber
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Institute for Photovoltaics, University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany.
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2
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Stetten AZ, Kratz FS, Schilderink N, Ayirala S, Duits MHG, Kierfeld J, Mugele F. Elastometry of Complex Fluid Pendant Capsules. Langmuir 2023; 39:16303-16314. [PMID: 37939256 PMCID: PMC10666541 DOI: 10.1021/acs.langmuir.3c01845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 11/10/2023]
Abstract
Oil/water interfaces are ubiquitous in nature. Opposing polarities at these interfaces attract surface-active molecules, which can seed complex viscoelastic or even solid interfacial structure. Biorelevant proteins such as hydrophobin, polymers such as PNIPAM, and the asphaltenes in crude oil (CRO) are examples of some systems where such layers can occur. When a pendant drop of CRO is aged in brine, it can form an interfacial elastic membrane of asphaltenes so stiff that it wrinkles and crumples upon retraction. Most of the work studying CRO/brine interfaces focuses on the viscoelastic liquid regime, leaving a wide range of fully solidified, elastic interfaces largely unexplored. In this work, we quantitatively measure elasticity in all phases of drop retraction. In early retraction, the interface shows a fluid viscoelasticity measurable using a Gibbs isotherm or dilatational rheology. Further retraction causes a phase transition to a 2D elastic solid with nonisotropic, nonhomogeneous surface stresses. In this regime, we use new techniques in the elastic membrane theory to fit for the elasticities of these solid capsules. These elastic measurements can help us develop a deeper understanding not only of CRO interfaces but also of the myriad fluid systems with solid interfacial layers.
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Affiliation(s)
- Amy Z. Stetten
- Physics
of Complex Fluids Group, University of Twente, 7500 AE Enschede, The Netherlands
| | - Felix S. Kratz
- Department
of Physics, TU Dortmund University, 44221 Dortmund, Germany
| | - Nathalie Schilderink
- Physics
of Complex Fluids Group, University of Twente, 7500 AE Enschede, The Netherlands
| | - Subhash Ayirala
- EXPEC
Advanced Research Center, Saudi Aramco, 34465 Dhahran, Saudi Arabia
| | - Michael H. G. Duits
- Physics
of Complex Fluids Group, University of Twente, 7500 AE Enschede, The Netherlands
| | - Jan Kierfeld
- Department
of Physics, TU Dortmund University, 44221 Dortmund, Germany
| | - Frieder Mugele
- Physics
of Complex Fluids Group, University of Twente, 7500 AE Enschede, The Netherlands
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3
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Le-Anh D, Rao A, Stetten AZ, Ayirala SC, Alotaibi MB, Duits MHG, Gardeniers H, AlYousef AA, Mugele F. Oil Displacement in Calcite-Coated Microfluidic Chips via Waterflooding at Elevated Temperatures and Long Times. Micromachines (Basel) 2022; 13:1316. [PMID: 36014237 PMCID: PMC9415086 DOI: 10.3390/mi13081316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
In microfluidic studies of improved oil recovery, mostly pore networks with uniform depth and surface chemistry are used. To better mimic the multiple porosity length scales and surface heterogeneity of carbonate reservoirs, we coated a 2.5D glass microchannel with calcite particles. After aging with formation water and crude oil (CRO), high-salinity Water (HSW) was flooded at varying temperatures and durations. Time-resolved microscopy revealed the CRO displacements. Precise quantification of residual oil presented some challenges due to calcite-induced optical heterogeneity and brine-oil coexistence at (sub)micron length scales. Both issues were addressed using pixel-wise intensity calibration. During waterflooding, most of the ultimately produced oil gets liberated within the first pore volume (similar to glass micromodels). Increasing temperature from 22 °C to 60 °C and 90 °C produced some more oil. Waterflooding initiated directly at 90 °C produced significantly more oil than at 22 °C. Continuing HSW exposure at 90 °C for 8 days does not release additional oil; although, a spectacular growth of aqueous droplets is observed. The effect of calcite particles on CRO retention is weak on flat surfaces, where the coverage is ~20%. The calcite-rich pore edges retain significantly more oil suggesting that, in our micromodel wall roughness is a stronger determinant for oil retention than surface chemistry.
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Affiliation(s)
- Duy Le-Anh
- Physics of Complex Fluids, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Ashit Rao
- Physics of Complex Fluids, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Amy Z. Stetten
- Physics of Complex Fluids, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Subhash C. Ayirala
- The Exploration and Petroleum Engineering Center-Advanced Research Center (EXPEC ARC), Saudi Aramco, Dhahran 34465, Saudi Arabia
| | - Mohammed B. Alotaibi
- The Exploration and Petroleum Engineering Center-Advanced Research Center (EXPEC ARC), Saudi Aramco, Dhahran 34465, Saudi Arabia
| | - Michel H. G. Duits
- Physics of Complex Fluids, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Han Gardeniers
- Mesoscale Chemical Systems Groups, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Ali A. AlYousef
- The Exploration and Petroleum Engineering Center-Advanced Research Center (EXPEC ARC), Saudi Aramco, Dhahran 34465, Saudi Arabia
| | - Frieder Mugele
- Physics of Complex Fluids, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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4
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Hages ND, Sembrat JC, Weber L, Johnston DJ, Stetten AZ, Sauleda M, Mulhern B, Tilton RD, Garoff S, Rojas M, Corcoran TE. Effect of a Surfactant Additive on Drug Transport and Distribution Uniformity After Aerosol Delivery to Ex Vivo Lungs. J Aerosol Med Pulm Drug Deliv 2022; 35:146-153. [PMID: 34647795 PMCID: PMC9242716 DOI: 10.1089/jamp.2021.0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Background: Inhaled drug delivery can be limited by heterogeneous dose distribution. An additive that would disperse drug over the internal surfaces of the lung after aerosol deposition could improve dosing uniformity and increase the treated area. Our previous studies demonstrated that surfactant additives can produce surface tension-driven (Marangoni) flows that effectively dispersed aerosol-delivered drugs over mucus surfaces. Here we sought to determine whether the addition of a surfactant would increase transport of an aerosol between lung regions and also improve dosing uniformity in human lungs. Methods: We compared the deposition and postdeposition dispersion of surfactant (10 mg/mL dipalmitoylphosphatidylcholine; DPPC) and saline-based liquid aerosols, admixed with Technetium 99m (Tc99m) diethylenetriaminepentaacetic acid, using gamma scintigraphy. Deposition images were obtained ex vivo in eight pairs of ventilated human lungs. The trachea was intubated and the mainstem bronchi were alternately clamped so that saline was delivered to one lung and then DPPC to the other (sides alternated). The lungs were continually imaged for 15 minutes during delivery. We assessed transport of the deposited aerosol by quantifying the percentage of Tc99m in each of four lung quadrants over time. We quantified dose uniformity within each lung quadrant by measuring the coefficient of variation (CV = standard deviation of the pixel associated radioactive counts/mean of the counts within each quadrant). Results: There was no change in the percentage of Tc99m in each quadrant over time, indicating no improvement in transport with the addition of the surfactant. The addition of surfactant was associated with a statistically significant decrease in CV in the lower inner lung quadrant at each of the three time points, indicating an improvement in dosing uniformity. Conclusion: These preliminary results indicate the possible utility of adding surfactant to aerosols to improve drug distribution uniformity to lower inner lung regions.
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Affiliation(s)
- Nicholas D. Hages
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - John C. Sembrat
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Lawrence Weber
- Department of Nuclear Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Darragh J. Johnston
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Amy Z. Stetten
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Madeline Sauleda
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Brian Mulhern
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Robert D. Tilton
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Stephen Garoff
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Mauricio Rojas
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Timothy E. Corcoran
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Address correspondence to: Timothy E. Corcoran, PhD, Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, UPMC MUH NW628, 3459 Fifth Avenue, Pittsburgh, PA 15213, USA.
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Abstract
We investigate the charge separation caused by the motion of a water drop across a hydrophobic, insulating solid surface. Although the phenomenon of liquid charging has been consistently reported, these reports are primarily observational, results are difficult to reproduce, and no quantitative theory has been developed. In this work, we address both the experimental and theoretical sides of this problem. We reproducibly measure the charge gained by water drops sliding down a substrate, and we outline an analytical theory to describe this charging process. As an experimental system, we choose water drops moving down an inclined plane of glass hydrophobized with perfluoro octadecyltrichlorosilane (PFOTS). On this surface, sliding drops gain a positive charge. We observe charge saturation in three variables: increasing drop number, increasing interval between drops, and increasing drop-sliding length. These charge saturations indicate a limited "storage capacity" of the system, as well as a gradual discharging of the surface. To explain these results, we theorize that some fraction of the charge in the Debye layer is transferred to the surface rather than being neutralized as the drop passes. This fraction, or "transfer coefficient", is dependent on the electric potentials of surface and drop. All of our experimental charge saturation results can be interpreted based on the proposed theory. Given that nearly every surface in our lives comes in contact with water, this water-dependent surface charging may be a ubiquitous process that we can begin to understand through the proposed theory.
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Affiliation(s)
- Amy Z Stetten
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Dmytro S Golovko
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Stefan A L Weber
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany. and Department of Physics, Johannes Gutenberg University, Staudingerweg 10, 55128 Mainz, Germany
| | - Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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6
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Stetten AZ, Iasella SV, Corcoran TE, Garoff S, Przybycien TM, Tilton RD. Surfactant-induced Marangoni transport of lipids and therapeutics within the lung. Curr Opin Colloid Interface Sci 2018; 36:58-69. [PMID: 30147429 PMCID: PMC6103298 DOI: 10.1016/j.cocis.2018.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Understanding the fundamentals of surface transport on thin viscous films has important application in pulmonary drug delivery. The human lung contains a large-area interface between its complex fluid lining and inhaled air. Marangoni flows driven by surface tension gradients along this interface would promote enhanced distribution of inhaled therapeutics by carrying them from where they are deposited in the upper airways, along the fluid interface to deeper regions of the lung. Motivated by the potential to improve therapies for acute and chronic lung diseases, we review recent progress in modeling and experimental studies of Marangoni transport induced by the deposition of surfactant-containing microliter drops and liquid aerosols (picoliter drops) onto a fluid interface. The roles of key system variables are identified, including surfactant solubility, drop miscibility with the subphase, and the thickness, composition and surface properties of the subphase liquid. Of particular interest is the unanticipated but crucial role of aerosol processing to achieve Marangoni transport via phospholipid vesicle dispersions, which are likely candidates for a biocompatible delivery system. Progress in this field has the potential to not only improve outcomes in patients with chronic and acute lung diseases, but also to further our understanding of surface transport in complex systems.
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Affiliation(s)
- Amy Z. Stetten
- Carnegie Mellon Center for Complex Fluids Engineering, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Steven V. Iasella
- Carnegie Mellon Center for Complex Fluids Engineering, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | | | - Stephen Garoff
- Carnegie Mellon Center for Complex Fluids Engineering, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Todd M. Przybycien
- Carnegie Mellon Center for Complex Fluids Engineering, Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Carnegie Mellon Center for Complex Fluids Engineering, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Robert D. Tilton
- Carnegie Mellon Center for Complex Fluids Engineering, Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Carnegie Mellon Center for Complex Fluids Engineering, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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7
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Stetten AZ, Treece BW, Corcoran TE, Garoff S, Przybycien TM, Tilton RD. Evolution and Disappearance of Solvent Drops on Miscible Polymer Subphases. Colloids Surf A Physicochem Eng Asp 2018; 546:266-275. [PMID: 30416264 DOI: 10.1016/j.colsurfa.2018.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Traditionally, an interface is defined as a boundary between immiscible phases. However, previous work has shown that even when two fluids are completely miscible, they maintain a detectable "effective interface" for long times. Miscible interfaces have been studied in various systems of two fluids with a single boundary between them. However, this work has not extended to the three-phase system of a fluid droplet placed on top of a miscible pool. We show that these three-phase systems obey the same wetting conditions as immiscible systems, and that their drop shapes obey the Augmented Young-Laplace Equation. Over time, the miscible interface diffuses and the shape of the drop evolves. We place 2-microliter drops of water atop miscible poly(acrylamide) solutions. The drop is completely wetted by the subphase, and then remains detectable beneath the surface for many minutes. An initial effective interfacial tension can be approximated to be on the order of 0.5 mN/m using the capillary number. Water and poly(acrylamide) are completely miscible in all concentrations, and yet, when viewed from the side, the drop maintains a capillary shape. Study of this behavior is important to the understanding of effective interfaces between miscible polymer phases, which are pervasive in nature.
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Affiliation(s)
- Amy Z Stetten
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Bradley W Treece
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Timothy E Corcoran
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Stephen Garoff
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Todd M Przybycien
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.,Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Robert D Tilton
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.,Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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Iasella SV, Stetten AZ, Corcoran TE, Garoff S, Przybycien TM, Tilton RD. Aerosolizing Lipid Dispersions Enables Antibiotic Transport Across Mimics of the Lung Airway Surface Even in the Presence of Pre-existing Lipid Monolayers. J Aerosol Med Pulm Drug Deliv 2017; 31:212-220. [PMID: 29053080 DOI: 10.1089/jamp.2017.1412] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Secondary lung infections are the primary cause of morbidity associated with cystic fibrosis lung disease. Aerosolized antibiotic inhalation is potentially advantageous but has limited effectiveness due to altered airway aerodynamics and deposition patterns that limit drug access to infected regions. One potential strategy to better reach infected areas is to formulate aerosols with surfactants that induce surface tension gradients and drive postdeposition drug dispersal via Marangoni transport along the airway surface liquid (ASL). Since this relies on surfactant-induced surface tension reduction, the presence of endogenous lipid monolayers may hinder drug dispersal performance. METHODS Tobramycin solutions were formulated with dipalmitoylphosphatidylcholine (DPPC), a major component of endogenous pulmonary surfactant, to drive postdeposition aerosol dispersal across a model ASL based on a liquid layer or "subphase" of aqueous porcine gastric mucin (PGM) solution with predeposited DPPC monolayers to mimic the endogenous surfactant. In vitro subphase samples were collected from regions outside the aerosol deposition zone and assayed for tobramycin concentration using a closed enzyme donor immunoassay. The motion of a tracking bead across the subphase surface and the corresponding decrease in surface tension on aerosol deposition were tracked both with and without a predeposited DPPC monolayer. The surface tension/area isotherm for DPPC on PGM solution subphase was measured to aid in the interpretation of the tobramycin dispersal behavior. RESULTS AND CONCLUSIONS Transport of tobramycin away from the deposition region occurs in aerosols formulated with DPPC whether or not predeposited lipid is present, and tobramycin concentrations are similar in both cases across biologically relevant length scales (∼8 cm). When DPPC is deposited from an aerosol, it induces ultralow surface tensions (<5 mN/m), which drive Marangoni flows, even in the presence of a dense background layer of DPPC. Therefore, aerosolized phospholipids, such as DPPC, will likely be effective spreading agents in the human lung.
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Affiliation(s)
- Steven V Iasella
- 1 Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Amy Z Stetten
- 2 Department of Physics, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Timothy E Corcoran
- 3 Department of Medicine, Pulmonary, Allergy, and Critical Care Division, University of Pittsburgh , Pittsburgh, Pennsylvania.,4 Department of Biomedical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Stephen Garoff
- 2 Department of Physics, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Todd M Przybycien
- 1 Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,4 Department of Biomedical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
| | - Robert D Tilton
- 1 Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania.,4 Department of Biomedical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania
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9
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Stetten AZ, Moraca G, Corcoran TE, Tristram-Nagle S, Garoff S, Przybycien TM, Tilton RD. Enabling Marangoni flow at air-liquid interfaces through deposition of aerosolized lipid dispersions. J Colloid Interface Sci 2016; 484:270-278. [PMID: 27623189 DOI: 10.1016/j.jcis.2016.08.076] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 11/29/2022]
Abstract
It has long been known that deposited drops of surfactant solution induce Marangoni flows at air-liquid interfaces. These surfactant drops create a surface tension gradient, which causes an outward flow at the fluid interface. We show that aqueous phospholipid dispersions may be used for this same purpose. In aqueous dispersions, phospholipids aggregate into vesicles that are not surface-active; therefore, drops of these dispersions do not initiate Marangoni flow. However, aerosolization of these dispersions disrupts the vesicles, allowing access to the surface-active monomers within. These lipid monomers do have the ability to induce Marangoni flow. We hypothesize that monomers released from broken vesicles adsorb on the surfaces of individual aerosol droplets and then create localized surface tension reduction upon droplet deposition. Deposition of lipid monomers via aerosolization produces surface tensions as low as 1mN/m on water. In addition, aerosolized lipid deposition also drives Marangoni flow on entangled polymer solution subphases with low initial surface tensions (∼34mN/m). The fact that aerosolization of phospholipids naturally found within pulmonary surfactant can drive Marangoni flows on low surface tension liquids suggests that aerosolized lipids may be used to promote uniform pulmonary drug delivery without the need for exogenous spreading agents.
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Affiliation(s)
- Amy Z Stetten
- Center for Complex Fluids Engineering, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Grace Moraca
- Center for Complex Fluids Engineering, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Timothy E Corcoran
- Center for Complex Fluids Engineering, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Stephanie Tristram-Nagle
- Center for Complex Fluids Engineering, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Stephen Garoff
- Center for Complex Fluids Engineering, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Todd M Przybycien
- Center for Complex Fluids Engineering, Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Center for Complex Fluids Engineering, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Robert D Tilton
- Center for Complex Fluids Engineering, Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Center for Complex Fluids Engineering, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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