1
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Arslanov VV, Ermakova EV, Krylov DI, Popova OO. On the relationship between the properties of planar structures of non-ionic surfactants and their vesicular analogues - Niosomes. J Colloid Interface Sci 2023; 640:281-295. [PMID: 36863184 DOI: 10.1016/j.jcis.2023.02.110] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/19/2023] [Accepted: 02/21/2023] [Indexed: 03/04/2023]
Abstract
In recent years, the study of niosomes as nanocarriers alternative to liposomes has received increasing attention. In contrast to well-studied liposome membranes, many aspects of the behavior of analogous niosome bilayers have not been studied. This paper considers one of these aspects related to the communication between the physicochemical properties of planar and vesicular objects. We present the first results of comparative studies of Langmuir monolayers of binary and ternary (with cholesterol) mixtures of non-ionic surfactants based on sorbitan esters and niosomal structures assembled from the same materials. The Thin-Film Hydration (TFH) method in the gentle shaking version was used to produce the particles of large sizes, while small unilamellar high quality vesicles with a unimodal distribution of particles were prepared by TFH using ultrasonic treatment and extrusion. An analysis of the structural organization and phase state of monolayers based on compression isotherms and supplemented by thermodynamic calculations, as well as the results of determining the particle morphology, polarity and microviscosity of niosome shells, made it possible to obtain fundamental data on the intermolecular interactions of the components and their packing in shells and to relate these data to the properties of niosomes. This relationship can be used to optimize the composition of niosome membranes and predict the behavior of these vesicular systems. It was shown that cholesterol excess creates regions of bilayers with increased rigidity (like "lipid rafts"), which hinders the process of folding film fragments into small niosomes.
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Affiliation(s)
- Vladimir V Arslanov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Pr. 31-4, Moscow 119071, Russia.
| | - Elizaveta V Ermakova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Pr. 31-4, Moscow 119071, Russia
| | - Daniil I Krylov
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Pr. 31-4, Moscow 119071, Russia
| | - Olga O Popova
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky Pr. 31-4, Moscow 119071, Russia
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2
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Patel R, Lacerda Q, Oeffinger BE, Eisenbrey JR, Rochani AK, Kaushal G, Wessner CE, Wheatley MA. Development of a Dual Drug-Loaded, Surfactant-Stabilized Contrast Agent Containing Oxygen. Polymers (Basel) 2022; 14:polym14081568. [PMID: 35458319 PMCID: PMC9027498 DOI: 10.3390/polym14081568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/01/2022] [Accepted: 04/07/2022] [Indexed: 02/08/2023] Open
Abstract
Co-delivery of cancer therapeutics improves efficacy and encourages synergy, but delivery faces challenges, including multidrug resistance and spatiotemporal distribution of therapeutics. To address these, we added paclitaxel to previously developed acoustically labile, oxygen-core, surfactant-stabilized microbubbles encapsulating lonidamine, with the aim of developing an agent containing both a therapeutic gas and two drugs acting in combination. Upon comparison of unloaded, single-loaded, and dual-loaded microbubbles, size (~1.7 µm) and yield (~2 × 109 microbubbles/mL) (~1.7) were not statistically different, nor were acoustic properties (maximum in vitro enhancements roughly 18 dB, in vitro enhancements roughly 18 dB). Both drugs encapsulated above required doses calculated for head and neck squamous cell carcinoma, the cancer of choice. Interestingly, paclitaxel encapsulation efficiency increased from 1.66% to 3.48% when lonidamine was included. During preparation, the combination of single drug-loaded micelles gave higher encapsulation (µg drug/g microbubbles) than micelles loaded with either drug alone (lonidamine, 104.85 ± 22.87 vs. 87.54 ± 16.41), paclitaxel (187.35 ± 8.38 vs. 136.51 ± 30.66). In vivo intravenous microbubbles produced prompt ultrasound enhancement within tumors lasting 3–5 min, indicating penetration into tumor vasculature. The ability to locally destroy the microbubble within the tumor vasculature was confirmed using a series of higher intensity ultrasound pulses. This ability to locally destroy microbubbles shows therapeutic promise that warrants further investigation.
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Affiliation(s)
- Raj Patel
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA; (R.P.); (Q.L.); (B.E.O.)
| | - Quezia Lacerda
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA; (R.P.); (Q.L.); (B.E.O.)
| | - Brian E. Oeffinger
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA; (R.P.); (Q.L.); (B.E.O.)
| | - John R. Eisenbrey
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA; (J.R.E.); (C.E.W.)
| | - Ankit K. Rochani
- Department of Pharmaceutical Sciences, Thomas Jefferson University, Philadelphia, PA 19107, USA; (A.K.R.); (G.K.)
| | - Gagan Kaushal
- Department of Pharmaceutical Sciences, Thomas Jefferson University, Philadelphia, PA 19107, USA; (A.K.R.); (G.K.)
| | - Corinne E. Wessner
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA; (J.R.E.); (C.E.W.)
| | - Margaret A. Wheatley
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA; (R.P.); (Q.L.); (B.E.O.)
- Correspondence:
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3
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Interplay between bulk aggregates, surface properties and foam stability of nonionic surfactants. Adv Colloid Interface Sci 2022; 302:102618. [PMID: 35245855 DOI: 10.1016/j.cis.2022.102618] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 02/15/2022] [Accepted: 02/20/2022] [Indexed: 11/21/2022]
Abstract
In our previous study (Mustan et al. 2021) we showed that foams formed from two oil-soluble nonionic surfactants (Span 60 and Brij 72) can remain stable for more than 10 days at room temperature at high sugar concentration. The major aim of the current study is to reveal the interrelation between the surfactant structure and foam stability by investigating 6 polyoxyethelene alkyl ethers and 12 fatty acid esters with a wide variety of hydrophobic chain lengths (C12; C16; C18 and C18:1) and hydrophilic head-groups (sorbitol, glycerol, sucrose). Foams stable for more than 100 days at room temperature are obtained when sucrose palmitate or stearate (P1670 or S1670) are used as surfactants. This exceptional foam stability is related to the gelation of the aqueous phase and to the formation of solid adsorption layer with zero surface tension upon compression, thus preventing water drainage and decelerating the bubble Ostwald ripening. The foam stability decreases with (i) increasing the number of EO groups in polyoxyethylene alkyl ethers and in fatty acid sorbitan esters; (ii) decreasing the number of C-atoms in the surfactant tail for all studied surfactants; (iii) addition of double bond in the surfactant tail. The lower foam stability in all three cases is related to the worse packing of the surfactant molecules within the adsorption layer, leading to faster Ostwald ripening and subsequent bubble coalescence. The diesters present as admixture in the fatty acid esters play an important role in the foam stabilization by further compacting the adsorption layers and lowering the rate of Ostwald ripening. These conclusions can be used as a predictive tool for surfactant selection in the development of food or pharmaceutical foam concentrates that can be diluted before final use.
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4
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Barmin RA, Rudakovskaya PG, Chernyshev VS, Guslyakova OI, Belcov PA, Obukhova EN, Gayer AV, Shirshin EA, Gorin DA. Optoacoustic/Fluorescent/Acoustic Imaging Probe Based on Air-Filled Bubbles Functionalized with Gold Nanorods and Fluorescein Isothiocyanate. ACS OMEGA 2021; 6:3809-3821. [PMID: 33585760 PMCID: PMC7876831 DOI: 10.1021/acsomega.0c05518] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 12/28/2020] [Indexed: 05/08/2023]
Abstract
Liquid/surfactant/gas interfaces are promising objects for nanoengineered multimodal contrasts, which can be used for biomedical imaging in preclinical and clinical applications. Microbubbles with the gaseous core and shell made of lipids/proteins have already acted as ultrasound (US) contrast agents for angiography. In the present work, microbubbles with a shell composed of Span 60 and Tween 80 surfactants functionalized with fluorescein isothiocyanate and gold nanorods to achieve a multimodal combination of US, fluorescence, and optoacoustic imaging are described. Optimal conditions for microbubble generation by studying the surface tension of the initial solutions and analyzing the size, stability, and charge of the resulting bubbles were found. By controlling and modifying bubbles' surface properties, an increase in stability and storage time can be achieved. The functionalization of bubbles with gold nanoparticles and a dye by using an optimally selected sonication protocol was performed. The biomedical application's potential in imaging modalities of functionalized microbubbles using a medical US device with a frequency of 50 MHz, fluorescence tomography, and raster-scanning optoacoustic mesoscopy measurements was evaluated. The obtained results are important for optimum stabilization and functionalization of gas/liquid interfaces and the following applications in the multimodal biomedical imaging.
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Affiliation(s)
- Roman A. Barmin
- Skolkovo
Institute of Science and Technology, 3 Nobelya Str., Moscow 121205, Russia
| | | | | | - Olga I. Guslyakova
- Saratov
State University, 83 Astrakhanskaya Str., Saratov 410012, Russia
| | - Pavel A. Belcov
- Anta-Med
Premium, LLC, 11 Derbenevskaya
Naberezhnaya, Moscow 115114, Russia
| | | | - Alexey V. Gayer
- Lomonosov
Moscow State University, 1/2 Leninskie Gory, Moscow 119991, Russia
| | - Evgeny A. Shirshin
- Lomonosov
Moscow State University, 1/2 Leninskie Gory, Moscow 119991, Russia
- Institute
of Spectroscopy of the Russian Academy of Sciences, 5 Fizicheskaya Str., Troitsk, Moscow 108840, Russia
- Institute
for Regenerative Medicine, Sechenov First
Moscow State Medical University, Trubetskaya 8-2, Moscow 119048, Russia
| | - Dmitry A. Gorin
- Skolkovo
Institute of Science and Technology, 3 Nobelya Str., Moscow 121205, Russia
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5
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Kilic S. Effect of Temperature on Stability of Lipid Microbubbles. JOURNAL OF THE TURKISH CHEMICAL SOCIETY, SECTION A: CHEMISTRY 2019. [DOI: 10.18596/jotcsa.594219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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6
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Oeffinger BE, Vaidya P, Ayaz I, Shraim R, Eisenbrey JR, Wheatley MA. Preserving the Integrity of Surfactant-Stabilized Microbubble Membranes for Localized Oxygen Delivery. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10068-10078. [PMID: 30827115 PMCID: PMC7041305 DOI: 10.1021/acs.langmuir.8b03725] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Ultrasound contrast agents consist of stabilized microbubbles. We are developing a surfactant-stabilized microbubble platform with a shell composed of Span 60 (Sorbitan monostearate) and an emulsifying agent, water-soluble vitamin E (α-tocopheryl poly(ethylene glycol) succinate, abbreviated as TPGS), named SE61. The microbubbles act both as an imaging agent and a vehicle for delivering oxygen to hypoxic areas in tumors. For clinical use, it is important that a platform be stable under storage at room temperature. To accomplish this, a majority of biologicals are prepared as freeze-dried powders, which also eliminates the necessity of a cold chain. The interfaces among the surfactants, gas, and liquids are subject to disruption in both the freezing and drying phases. Using thermocouples to monitor temperature profiles, differential scanning calorimetry to determine the phase transitions, and acoustic properties to gauge the degree of microbubble disruption, the effects of the freezing rate and the addition of different concentrations of lyoprotectants were determined. Slower cooling rates achieved by freezing the samples in a -20 °C bath were found to be reproducible and produce contrast agents with acceptable acoustical properties. The ionic strength of the solutions and the concentration of the lyoprotectant determined the glass-transition temperature (Tg') of the frozen sample, which determines at what temperature samples can be dried without collapse. Crucially, we found that the shelf stability of surfactant-shelled oxygen microbubbles can be enhanced by increasing the lyoprotectant (glucose) concentration from 1.8 to 5.0% (w/v), which prevents the melt temperature (Tm) of the TPGS phase from rising above room temperature. The increase in glucose concentration results in a lowering of Tm of the emulsifying agent, preventing a phase change in the liquid-crystalline phase and allowing for more stable bubbles. We believe that preventing this phase change is necessary to producing stabilized freeze-dried microbubbles.
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Affiliation(s)
- Brian E. Oeffinger
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Purva Vaidya
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Iman Ayaz
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Rawan Shraim
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - John R. Eisenbrey
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
| | - Margaret A. Wheatley
- School of Biomedical Engineering Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
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7
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Juang EK, De Cock I, Keravnou C, Gallagher MK, Keller SB, Zheng Y, Averkiou M. Engineered 3D Microvascular Networks for the Study of Ultrasound-Microbubble-Mediated Drug Delivery. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10128-10138. [PMID: 30540481 DOI: 10.1021/acs.langmuir.8b03288] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Localized and targeted drug delivery can be achieved by the combined action of ultrasound and microbubbles on the tumor microenvironment, likely through sonoporation and other therapeutic mechanisms that are not well understood. Here, we present a perfusable in vitro model with a realistic 3D geometry to study the interactions between microbubbles and the vascular endothelium in the presence of ultrasound. Specifically, a three-dimensional, endothelial-cell-seeded in vitro microvascular model was perfused with cell culture medium and microbubbles while being sonicated by a single-element 1 MHz focused transducer. This setup mimics the in vivo scenario in which ultrasound induces a therapeutic effect in the tumor vasculature in the presence of flow. Fluorescence and bright-field microscopy were employed to assess the microbubble-vessel interactions and the extent of drug delivery and cell death both in real time during treatment as well as after treatment. Propidium iodide was used as the model drug while calcein AM was used to evaluate cell viability. There were two acoustic parameter sets chosen for this work: (1) acoustic pressure: 1.4 MPa, pulse length: 500 cycles, duty cycle: 5% and (2) acoustic pressure: 0.4 MPa, pulse length: 1000 cycles, duty cycle: 20%. Enhanced drug delivery and cell death were observed in both cases while the higher pressure setting had a more pronounced effect. By introducing physiological flow to the in vitro microvascular model and examining the PECAM-1 expression of the endothelial cells within it, we demonstrated that our model is a good mimic of the in vivo vasculature and is therefore a viable platform to provide mechanistic insights into ultrasound-mediated drug delivery.
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Affiliation(s)
- Eric K Juang
- Department of Bioengineering , University of Washington , Seattle , Washington 98195 , United States
| | - Ine De Cock
- Department of Bioengineering , University of Washington , Seattle , Washington 98195 , United States
| | - Christina Keravnou
- Department of Bioengineering , University of Washington , Seattle , Washington 98195 , United States
| | - Madison K Gallagher
- Department of Bioengineering , University of Washington , Seattle , Washington 98195 , United States
| | - Sara B Keller
- Department of Bioengineering , University of Washington , Seattle , Washington 98195 , United States
| | - Ying Zheng
- Department of Bioengineering , University of Washington , Seattle , Washington 98195 , United States
| | - Michalakis Averkiou
- Department of Bioengineering , University of Washington , Seattle , Washington 98195 , United States
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8
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Fu JW, Lin YS, Gan SL, Li YR, Wang Y, Feng ST, Li H, Zhou GF. Multifunctionalized Microscale Ultrasound Contrast Agents for Precise Theranostics of Malignant Tumors. CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:3145647. [PMID: 31360144 PMCID: PMC6642784 DOI: 10.1155/2019/3145647] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/26/2019] [Accepted: 06/10/2019] [Indexed: 11/17/2022]
Abstract
In ultrasonography, ultrasound contrast agents (UCAs) that possess high acoustic impedance mismatch with the bulk medium are frequently employed to highlight the borders between tissues by enhanced ultrasound scattering in a clinic. Typically, the most common UCA, microbubble, is generally close in size to a red blood cell (<∼10 μm). These microscale UCAs cannot be directly entrapped into the target cells but generate several orders of magnitude stronger echo signals than the nanoscale ones. And their large containment and high ultrasound responsiveness also greatly facilitate to perform combined treatments, e.g., drug delivery and other imaging techniques. So multifunctionalized microscale UCAs appear on this scene and keep growing toward a promising direction for precise theranostics. In this review, we systematically summarize the new advances in the principles and preparations of multifunctionalized microscale UCAs and their medical applications for malignant tumors.
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Affiliation(s)
- Jia-Wei Fu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, China
| | - Yi-Sheng Lin
- Department of Radiology, The First Affiliated Hospital, Guangzhou University of Traditional Chinese Medicine, Guangzhou, Guangdong 510405, China
| | - Sheng-Long Gan
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, China
| | - Yong-Rui Li
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, China
| | - Yao Wang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, China
| | - Shi-Ting Feng
- Department of Radiology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Hao Li
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, China
| | - Guo-Fu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou 510006, China
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9
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Kilic S. Quantification of PEG40St squeeze out from DSPC/PEG40St monolayers at higher molar ratios. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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10
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Temperature-Dependent Phase Behavior of Langmuir Films of 10,12-Pentacosadiynoic Acid at the Air/Water Interface and Its Effects on Chromatic Stability of the Polymerized Langmuir-Schaefer Films. Macromol Res 2018. [DOI: 10.1007/s13233-018-6071-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Kheir JN, Polizzotti BD, Thomson LM, O'Connell DW, Black KJ, Lee RW, Wilking JN, Graham AC, Bell DC, McGowan FX. Bulk manufacture of concentrated oxygen gas-filled microparticles for intravenous oxygen delivery. Adv Healthc Mater 2013; 2:1131-41. [PMID: 23471884 DOI: 10.1002/adhm.201200350] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 11/21/2012] [Indexed: 12/25/2022]
Abstract
Self-assembling, concentrated, lipid-based oxygen microparticles (LOMs) have been developed to administer oxygen gas when injected intravenously, preventing organ injury and death from systemic hypoxemia in animal models. Distinct from blood substitutes, LOMs are a one-way oxygen carrier designed to rescue patients who experience life-threatening hypoxemia, as caused by airway obstruction or severe lung injury. Here, we describe methods to manufacture large quantities of LOMs using an in-line, recycling, high-shear homogenizer, which can create up to 4 liters of microparticle emulsion in 10 minutes, with particles containing a median diameter of 0.93 microns and 60 volume% of gas phase. Using this process, we screen 30 combinations of commonly used excipients for their ability to form stable LOMs. LOMs composed of DSPC and cholesterol in a 1:1 molar ratio are stable for a 100 day observation period, and the number of particles exceeding 10 microns in diameter does not increase over time. When mixed with blood in vitro, LOMs fully oxygenate blood within 3.95 seconds of contact, and do not cause hemolysis or complement activation. LOMs can be manufactured in bulk by high shear homogenization, and appear to have a stability and size profile which merit further testing.
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Affiliation(s)
- John N Kheir
- Department of Cardiology, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Enders 1228, Boston, Massachusetts 02115 USA.
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12
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Azmin M, Mohamedi G, Edirisinghe M, Stride E. Dissolution of coated microbubbles: The effect of nanoparticles and surfactant concentration. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012. [DOI: 10.1016/j.msec.2012.06.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Robert de Saint Vincent M, Delville JP. Thermocapillary migration in small-scale temperature gradients: application to optofluidic drop dispensing. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:026310. [PMID: 22463320 DOI: 10.1103/physreve.85.026310] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Indexed: 05/31/2023]
Abstract
We experimentally investigate the thermocapillary migration induced by local laser heating of the advancing front of a growing droplet confined in a microfluidic channel. When heating implies an effective increase in interfacial tension, the laser behaves as a "soft door" whose stiffness can be tuned via the optical parameters (beam power and waist). The light-driven thermocapillary velocity of a growing droplet, which opposes the basic flow, is characterized for different types of fluid injection, either pressure or flow rate driven, and various channel aspect ratios. Measurements are interpreted using a simplified model for the temperature gradient at the interface, based on a purely diffusive, three-layer system. Considering the mean temperature gradient, we demonstrate that the classical large-scale temperature gradient behavior is retrieved in the opposite case when the thermal gradient length scale is smaller than the droplet size. We also demonstrate that the thermocapillary velocity is proportional to the smallest droplet curvature imposed by the channel confinement. This suggests that the thermocapillary velocity is in fact proportional to the mean temperature gradient and to the largest interface curvature radius, which both coincide with the imposed one and the spherical droplet radius in large-scale and unconfined situations. Furthermore, as used surfactant concentrations are largely above the critical micelle concentration, we propose a possible explanation, relying on state-of-the-art considerations on high-concentration surfactant-covered interfaces for the observed effective increase in interfacial tension with temperature. We also propose a mechanism for explaining the blocking effect at the scaling-law level. This mechanism involves the temporal evolution of hydrodynamic and thermocapillary forces, based on experimental observations. We finally show that this optocapillary interaction with a microfluidic droplet generator allows for controlling either the flow rate (valve) or the droplet size (sampler), depending on the imposed fluid injection conditions.
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14
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Ekemen Z, Chang H, Ahmad Z, Bayram C, Rong Z, Denkbas EB, Stride E, Vadgama P, Edirisinghe M. Fabrication of Biomaterials via Controlled Protein Bubble Generation and Manipulation. Biomacromolecules 2011; 12:4291-300. [DOI: 10.1021/bm201202y] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zeynep Ekemen
- Department of Mechanical Engineering, University College London, Torrington Place, London
WC1E 7JE, United Kingdom
| | - Hong Chang
- IRC in Biomedical Materials, Queen Mary University of London, Mile End Road, London
E1 4NS, United Kingdom
| | - Zeeshan Ahmad
- School
of Pharmacy and Biomedical
Sciences, University of Portsmouth, St
Michael’s Building, White Swan Road, Portsmouth, PO1 2DT, United
Kingdom
| | - Cem Bayram
- Nanotechnology
and Nanomedicine
Division, The Institute For Graduate Studies in Science and Engineering, Hacettepe University, 06800, Ankara, Turkey
| | - Zimei Rong
- IRC in Biomedical Materials, Queen Mary University of London, Mile End Road, London
E1 4NS, United Kingdom
| | - Emir Baki Denkbas
- Nanotechnology
and Nanomedicine
Division, The Institute For Graduate Studies in Science and Engineering, Hacettepe University, 06800, Ankara, Turkey
| | - Eleanor Stride
- Department of Mechanical Engineering, University College London, Torrington Place, London
WC1E 7JE, United Kingdom
| | - Pankaj Vadgama
- IRC in Biomedical Materials, Queen Mary University of London, Mile End Road, London
E1 4NS, United Kingdom
| | - Mohan Edirisinghe
- Department of Mechanical Engineering, University College London, Torrington Place, London
WC1E 7JE, United Kingdom
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15
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Ma H, Perea B, Dai LL. Study of two-component colloidal particles at air/water interfaces using Langmuir–Blodgett techniques. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2010.09.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Xing Z, Ke H, Wang J, Zhao B, Yue X, Dai Z, Liu J. Novel ultrasound contrast agent based on microbubbles generated from surfactant mixtures of Span 60 and polyoxyethylene 40 stearate. Acta Biomater 2010; 6:3542-9. [PMID: 20226284 DOI: 10.1016/j.actbio.2010.03.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 01/15/2010] [Accepted: 03/03/2010] [Indexed: 11/27/2022]
Abstract
In this study, novel perfluorocarbon-filled microbubbles as ultrasound contrast agent were fabricated using ultrasonication of a surfactant mixture of sorbitan monostearate (Span 60) and polyoxyethylene 40 stearate (PEG40S) in aqueous media. The microbubbles generated from a 1:9 mixture of PEG40S/Span 60 exhibited an average diameter of 2.08+/-1.27 microm. More than 99% of the microbubbles had a mean particle diameter less than 8 microm, indicating that they were appropriately sized for intravenous administration as ultrasound contrast agent. The stabilization mechanism of the microbubbles was investigated by the Langmuir-Blodgett technique including the measurements of surface pressure-area (pi-A) isotherms and compression-decompression cycles with a two-dimensional monolayer of Span 60 and PEG40S. The dependence on molar fraction of PEG40S in pi-A isotherms of mixed monolayers provided a strong evidence of interactions between the two microbubble-forming materials. It is suggested that the monolayer shell imparts good stability to the microbubbles by three means: (1) a low surface tension monolayer hinders dissolution through the reduction of surface tension, which introduces a mechanical surface pressure that counters the Laplace pressure; (2) the presence of a monolayer shell imparts a significant barrier to gas escaping from the core into the aqueous medium; and (3) encapsulation elasticity stabilizes microbubbles against diffusion-driven dissolution and explains the long shelf-life of microbubble contrast agent. The preliminary in vivo ultrasound imaging study showed that such stabilized microbubbles demonstrated excellent enhancement under grey-scale pulse inversion harmonic imaging and power Doppler imaging.
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Forsberg F, Liu JB, Patel M, Liu L, Lin L, Solis C, Fox TB, Wheatley MA. Preclinical acute toxicology study of surfactant-stabilized ultrasound contrast agents in adult rats. Int J Toxicol 2009; 29:32-9. [PMID: 20008819 DOI: 10.1177/1091581809354342] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Gas-filled microbubbles are used as contrast agents in diagnostic ultrasound imaging. A preclinical, acute toxicity study of 2 surfactant-stabilized ultrasound contrast agents (ST68 and ST44) was conducted. Subjects were 104 Sprague-Dawley rats (experimental doses, 0.1, 0.2, 0.8, and 1.0 mL/kg; control, 1.0 mL/kg saline) that were studied for 14 days after contrast; clinical signs, weight, blood, and urine were evaluated. Histopathology was performed following euthanasia. Of the 40 animals receiving ST44, 4 died prematurely and a dose dependency was demonstrated (P = .011), whereas in the ST68 groups only 1 death occurred (no dose dependency; P = .48). Only the weight of rats injected with ST44 varied significantly (P = .0003). This dependency was also found for 3 of 5 urine parameters and 4 of 36 blood parameters (P < .05). For ST68, only 1 urine parameter showed significance (P < .0001). Giant cell infiltration in the lungs was significantly higher than controls in the ST44 0.1 mL/kg and the ST68 0.8-1.0 mL/kg groups (P < .01). It is concluded that the prudent choice for future nonrodent, toxicology studies and potentially for human clinical trials is ST68 (given the deaths in the ST44 groups).
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Affiliation(s)
- Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA, USA.
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Effects of encapsulation elasticity on the stability of an encapsulated microbubble. J Colloid Interface Sci 2009; 336:519-25. [PMID: 19524251 DOI: 10.1016/j.jcis.2009.05.019] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 05/04/2009] [Accepted: 05/06/2009] [Indexed: 11/22/2022]
Abstract
A model for gas transport from an encapsulated microbubble into the surrounding medium is developed and investigated incorporating the effects of encapsulation elasticity. Encapsulation elasticity stabilizes microbubbles against dissolution and explains the long shelf life of microbubble contrast agent. We consider air bubbles as well as bubbles containing perfluorocarbon gas. Analytical conditions between saturation level, surface tension and interfacial dilatational elasticity are determined for attaining non-zero equilibrium radius for these microbubbles. Numerical solution of the equation verifies the stability of the equilibrium radii. In an undersaturated medium all encapsulated bubbles dissolve. In a saturated medium, an encapsulated bubble is found to achieve a long-time stable radius when interfacial dilatational elasticity is larger than equilibrium surface tension. For bubbles with interfacial dilatational elasticity smaller than the equilibrium surface tension, stable bubble of non-zero radius can be achieved only when the saturation level is greater than a critical value. Even if they initially contain a gas other than air, bubbles that reach a stable radius finally become air bubbles. The model is applied to an octafluoropropane filled lipid-coated 2.5 microm bubble, which displayed a transient swelling due to air intake before reaching an equilibrium size. Effects of elasticity, shell permeability, initial mole fraction, initial radius and saturation level are investigated and discussed. Shell permeability and mole fraction do not affect the final equilibrium radius of the microbubble but affect the time scale and the transient dynamics. Similarly, the ratio of equilibrium radius to initial radius remains unaffected by the variation in initial radius.
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Novel preparation techniques for controlling microbubble uniformity: a comparison. Med Biol Eng Comput 2009; 47:883-92. [DOI: 10.1007/s11517-009-0490-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Accepted: 04/13/2009] [Indexed: 11/26/2022]
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Farook U, Stride E, Edirisinghe MJ. Preparation of suspensions of phospholipid-coated microbubbles by coaxial electrohydrodynamic atomization. J R Soc Interface 2009; 6:271-7. [PMID: 18647738 PMCID: PMC2659581 DOI: 10.1098/rsif.2008.0225] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The use of phospholipid-coated microbubbles for medical applications is gaining considerable attention. However, the preparation of lipid-coated microbubble suspensions containing the ideal size and size distribution of bubbles still represents a considerable challenge. The most commonly used preparation methods of sonication and mechanical agitation result in the generation of polydisperse microbubbles with diameters ranging from less than 1 microm to greater than 50 microm. Efforts have been made via distinctly different techniques such as microfluidic and electrohydrodynamic bubbling to prepare lipid-coated microbubbles with diameters less than 10 microm and with a narrow size distribution, and recent results have been highly promising. In this paper, we describe a detailed investigation of the latter method that essentially combines liquid and air flow, and an applied electric field to generate microbubbles. A parametric plot was constructed between the air flow rate (Qg) and the lipid suspension flow rate (Ql) to identify suitable flow rate regimes for the preparation of phospholipid-coated microbubbles with a mean diameter of 6.6 microm and a standard deviation of 2.5 microm. The parametric plot has also helped in developing a scaling equation between the bubble diameter and the ratio Qg/Ql. At ambient temperature (22 degrees C), these bubbles were very stable with their size remaining almost unchanged for 160 min. The influence of higher temperatures such as the human body temperature (37 degrees C) on the size and stability of the microbubbles was also explored. It was found that the mean bubble diameter fell rapidly to begin with but then stabilized at 1-2 microm after 20 min.
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Affiliation(s)
- U Farook
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
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Farook U, Stride E, Edirisinghe MJ. Stability of microbubbles prepared by co-axial electrohydrodynamic atomisation. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 38:713-8. [PMID: 19132365 DOI: 10.1007/s00249-008-0391-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 12/03/2008] [Accepted: 12/07/2008] [Indexed: 11/27/2022]
Abstract
Previous studies have indicated that microbubbles prepared by co-axial electrohydrodynamic atomisation (CEHDA) are less stable than those prepared by other methods such as sonication and microfluidic techniques. The aim of this investigation was to determine the reasons for this observation and how this might be addressed in future work. Microbubbles were prepared by CEHDA using (i) a glycerol-air system, (ii) a glycerol-Tween 80-air system and (iii) a glycerol-zirconia-air system and also by simple agitation of (i) and (ii), in order to compare the effect upon the dissolution rate of microbubbles of different materials and processing methods. Both theoretical examination and the experimental results indicated that all three quantities were important in controlling the rate of microbubble dissolution, namely: surface tension at the gas/liquid interface, the effective diffusivity of gas through this interface and the initial concentration of gas dissolved in the surrounding liquid. However, it was the difference in gas concentration in the surrounding liquid that was indicated as the primary reason for the differences in stability observed with different processing methods. It was concluded, therefore, that improved stability could be achieved for microbubbles prepared using CEHDA by saturating the collecting fluid with gas and/or maintaining a high concentration of microbubbles during collection.
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Affiliation(s)
- U Farook
- Department of Mechanical Engineering, University College London, Torrington Place, London, UK
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Rossi S, Waton G, Krafft MP. Small Phospholipid-Coated Gas Bubbles Can Last Longer than Larger Ones. Chemphyschem 2008; 9:1982-5. [DOI: 10.1002/cphc.200800386] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
Interest in microbubbles as vehicles for drug delivery has grown in recent years, due in part to characteristics that make them well suited for this role and in part to the need the for localized delivery of drugs in a number of applications. Microbubbles are inherently small, allowing transvascular passage, they can be functionalized for targeted adhesion, and can be acoustically driven, which facilitates ultrasound detection, production of bioeffects and controlled release of the cargo. This article provides an overview of related microbubble biofluid mechanics and reviews recent developments in the application of microbubbles for targeted drug delivery. Additionally, related advances in non-bubble microparticles for drug delivery are briefly described in the context of targeted adhesion.
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Affiliation(s)
- Joseph L Bull
- The University of Michigan, Department of Biomedical Engineering, 2142 Lurie Biomedical Engineering Building, 1107 Beal Avenue, Ann Arbor, MI 48109, USA.
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Cho SH, Kim JY, Kim JD. Dynamic surface tension of stable air-filled microbubbles prepared by freeze-drying a solution of lipid/surfactant mixture. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2006.02.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Taylor R, Hnatovsky C. Trapping and mixing of particles in water using a microbubble attached to an NSOM fiber probe. OPTICS EXPRESS 2004; 12:916-928. [PMID: 19474902 DOI: 10.1364/opex.12.000916] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Low power cw laser radiation at lambda=1.32microm was coupled into a chemically etched,metalized Near-Field Scanning Optical Microscopy (NSOM) fiber probe to generate a stable microbubble in water as well as in other fluids.The microbubble,which was attached to the end face of the fiber probe,was used to trap, manipulate and mix micron sized glass,latex and fluorescent particles as well as biological material.
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Forsberg F, Basude R, Liu JB, Alessandro J, Shi WT, Rawool NM, Goldberg BB, Wheatley MA. Effect of filling gases on the backscatter from contrast microbubbles: theory and in vivo measurements. ULTRASOUND IN MEDICINE & BIOLOGY 1999; 25:1203-1211. [PMID: 10576263 DOI: 10.1016/s0301-5629(99)00079-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two surfactant-based contrast agents, ST44 and ST68, were produced according to US Patent # 5,352,436 and filled with either air, C4F10 (perfluorobutane) or SF6 (sulfur hexaflouride). Ten rabbits received i.v. injections of each agent/gas combination with 5 repetitions of each dose (range: 0.005-0.13 mL/kg). A custom-made 10-MHz cuff transducer was placed around the surgically exposed distal aorta and audio Doppler signals were acquired in vivo. Quantitative in vivo dose responses were calculated off-line using spectral power analysis and compared to a theoretical model of microbubble dissolution and enhancement. For qualitative comparisons, 10 rabbits were imaged pre- and postcontrast administration (dose: 0.1 mL/kg) in gray-scale and colour. All agent/gas combinations produced marked Doppler enhancement with air bubbles enhancing least of all (p < 0.0001) and ST68-SF6 best of all (maximum: 27.6 +/- 2.04 dB; p < 0.012). There were no significant differences between other agent/gas combinations (0.30 < p < 0.70). Theoretical enhancement was within 1 order of magnitude of the experimental observations (i.e., deviations of up to 10 dB). The duration of contrast enhancement was 1-2 min for air-filled bubbles, 3-5 min for SF6-filled bubbles and more than 7 min for C4F10-filled bubbles. In conclusion, ST68-SF6 microbubbles produced most in vivo enhancement of the agent/gas combinations studied. Theory matched the measurements within an order of magnitude.
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Affiliation(s)
- F Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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