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Hayes DG, Barth BA, Pingali SV. Effect of equilibration time on the structural gradient in the vertical direction for bicontinuous microemulsions in Winsor-III and -IV systems. SOFT MATTER 2024. [PMID: 38651769 DOI: 10.1039/d3sm01741a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Bicontinuous microemulsions (BMEs), self-assembly systems consisting of oil and water nanodomains separated by surfactant monolayers, have many applications. However, changes in structure and properties of BMEs in the vertical direction can affect BMEs' utility. This study's objective was to determine the effect of equilibration time (τeq) on structural changes in the vertical direction for bicontinuous phases of Winsor-III (WIII) systems in situ or after being isolated, for D2O + H2O/1-dodecane/sodium dodecyl sulfate (SDS)/1-pentanol/NaCl at 22 °C. Small-angle neutron scattering (SANS) measurements were performed using a vertical stage sample environment that precisely aligned samples in the neutron beam. SANS data were fitted by the Teubner-Strey (TS) model and changes in TS-derived parameter values were observed. For 10 min ≤ τeq ≤ 4 h, the effective activity of the bicontinuous phase's surfactant monolayers increased with time at all vertical positions. At short equilibration (τeq = 10 min), small but significant amounts of water and oil were transiently emulsified near the WIII upper liquid-liquid interface. WIII systems underwent a relaxation process after being transferred to narrow 1 mm pathlength cells, resulting in a decrease of surfactant activity for the top half of the bicontinuous phase. For isolated bicontinuous phases, results suggest that SDS was desorbed from the BMEs by quartz near the bottom, while near the top, the water concentration near was relatively high. The results suggest that WIII systems should equilibrate for at least 4 hours after being prepared and transferred to a container that differs in cross sectional area and surfactant behavior in BMEs can change near interfaces.
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Affiliation(s)
- Douglas G Hayes
- Department of Biosystems Engineering and Soil Science, University of Tennessee, 2506 E.J. Chapman Drive, Knoxville, TN 37996-4531, USA.
| | - Brian A Barth
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 1512 Middle Dr, Knoxville, TN 37996, USA.
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Oehler MA, Hayes DG, D’Souza DH, Senanayake M, Gurumoorthy V, Pingali SV, O’Neill HM, Bras W, Urban VS. Assessment of antimicrobial activity of melittin encapsulated in bicontinuous microemulsions prepared using renewable oils. J SURFACTANTS DETERG 2023; 26:387-399. [PMID: 37470058 PMCID: PMC10353728 DOI: 10.1002/jsde.12654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/13/2022] [Indexed: 12/29/2022]
Abstract
The objective of this study is to demonstrate that melittin, a well-studied antimicrobial peptide (AMP), can be solubilized in an active form in bicontinuous microemulsions (BMEs) that employ biocompatible oils. The systems investigated consisted of Winsor-III and -IV BME phases composed of Water/Aerosol-OT (AOT)/Polysorbate 85/isopropyl myristate and a Winsor-IV BME employing Polysorbate 80 and limonene. We found that melittin resided in an α-helix-rich configuration and was in an apolar environment for the AOT/Polysorbate 85 Winsor-III system, suggesting that melittin interacted with the surfactant monolayer and was in an active conformation. An apolar environment was also detected for melittin in the two Winsor-IV systems, but to a lesser extent than the Winsor-III system. Small-angle X-ray scattering analysis indicated that melittin at a concentration of 1.0 g/Laq in the aqueous subphase of the Winsor-IV systems led to the greatest impact on the BME structure (e.g., decrease of quasi-periodic repeat distance and correlation length and induction of interfacial fluidity). The antimicrobial activity of the Polysorbate 80 Winsor-IV system was evaluated against several bacteria prominent in chronic wounds and surgical site infections (SSIs). Melittin-free BMEs inhibited the growth of all tested bacteria due to its oil, limonene, while the inclusion of 1.0 g/Laq of melittin in the BMEs enhanced the activity against several bacteria. A further increase of melittin concentration in the BMEs had no further enhancement. These results demonstrate the potential utility of BMEs as a delivery platform for AMPs and other hydrophilic and lipophilic drugs to inhibit antibiotic-resistant microorganisms in chronic wounds and SSIs.
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Affiliation(s)
- Madison A. Oehler
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee, USA
| | - Douglas G. Hayes
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee, USA
| | - Doris H. D’Souza
- Department of Food Science, University of Tennessee, Knoxville, Tennessee, USA
| | - Manjula Senanayake
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | | | - Sai Venkatesh Pingali
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Hugh M. O’Neill
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Wim Bras
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Volker S. Urban
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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3
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Tubtimsri S, Weerapol Y, Soontaranon S, Limmatvapirat C, Limmatvapirat S. Monolaurin-Loaded Gel-Like Microemulsion for Oropharyngeal Candidiasis Treatment: Structural Characterisation and In Vitro Antifungal Property. AAPS PharmSciTech 2022; 23:87. [PMID: 35292880 DOI: 10.1208/s12249-022-02235-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 02/09/2022] [Indexed: 11/30/2022] Open
Abstract
Recently, monolaurin (ML) has received great interest due to its possible use as an alternative antifungal. However, the limited water solubility of ML is still a major obstacle to its formulation and application. Gel-like microemulsions are one of the promising carriers for low-water-solubility substances due to both the advantages of gels and microemulsions and may be applied for ML. In this study, ML was incorporated into gel-like microemulsions and evaluated for its physicochemical and antifungal properties. The results indicated that the properties of gel-like microemulsion changed after the incorporation of ML, suggesting that ML can induce the transition of internal structure. When simulating the oral cavity environment, changes in the microstructure were observed and depended on the times of dilution. The lamellar structure was formed at 1.5-2 times dilution. However, this structure was disrupted after dilution five times or more. The structural change following dilution was associated with the release profiles. After contacting the formulations with the medium, ML was promptly released, with the majority of ML being released within 2 h. Regarding the antifungal assay, the ML-loaded gel-like microemulsions decreased the survival of Candida albicans within 3 h, although ML was immediately released, suggesting that the ML-loaded in oil droplets required time to permeate through the fungal cell wall. Additionally, the gel-like microemulsions possessed acceptable stability after the temperature cycling test. Therefore, gel-like microemulsions can be a possible carrier for ML loading, and ML-loaded gel-like microemulsions may be applied as an alternative antifungal preparation in the future. Graphical abstract.
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Eid BG, Alhakamy NA, Fahmy UA, Ahmed OAA, Md S, Abdel-Naim AB, Caruso G, Caraci F. Melittin and diclofenac synergistically promote wound healing in a pathway involving TGF-β1. Pharmacol Res 2022; 175:105993. [PMID: 34801680 DOI: 10.1016/j.phrs.2021.105993] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 12/23/2022]
Abstract
A dysregulation of the wound healing process can lead to the development of various intractable ulcers or excessive scar formation. Therefore it is essential to identify novel pharmacological strategies to promote wound healing and restore the mechanical integrity of injured tissue. The goal of the present study was to formulate a nano-complex containing melittin (MEL) and diclofenac (DCL) with the aim to evaluate their synergism and preclinical efficacy in an in vivo model of acute wound. After its preparation and characterization, the therapeutic potential of the combined nano-complexes was evaluated. MEL-DCL nano-complexes exhibited better regenerated epithelium, keratinization, epidermal proliferation, and granulation tissue formation, which in turn showed better wound healing activity compared to MEL, DCL, or positive control. The nano-complexes also showed significantly enhanced antioxidant activity. Treatment of wounded skin with MEL-DCL nano-complexes showed significant reduction of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) pro-inflammatory markers that was paralleled by a substantial increase in mRNA expression levels of collagen, type I, alpha 1 (Col1A1) and collagen, type IV, alpha 1 (Col4A1), and hydroxyproline content as compared to individual drugs. Additionally, MEL-DCL nano-complexes were able to significantly increase hypoxia-inducible factor 1-alpha (HIF-1α) and transforming growth factor beta 1 (TGF-β1) proteins expression compared to single drugs or negative control group. SB431542, a selective inhibitor of type-1 TGF-β receptor, significantly prevented in our in vitro assay the wound healing process induced by the MEL-DCL nano-complexes, suggesting a key role of TGF-β1 in the wound closure. In conclusion, the nano-complex of MEL-DCL represents a novel pharmacological tool that can be topically applied to improve wound healing.
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Affiliation(s)
- Basma G Eid
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Nabil A Alhakamy
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Advanced Drug Delivery Research Group, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Center of Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Scientific chair "Mohamed Saeed Tamer Chair for Pharmaceutical industries", King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Usama A Fahmy
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Osama A A Ahmed
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Advanced Drug Delivery Research Group, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Center of Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Scientific chair "Mohamed Saeed Tamer Chair for Pharmaceutical industries", King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Shadab Md
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ashraf B Abdel-Naim
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Giuseppe Caruso
- Department of Drug and Health Sciences, University of Catania, 95125 Catania, Italy.
| | - Filippo Caraci
- Department of Drug and Health Sciences, University of Catania, 95125 Catania, Italy; Oasi Research Institute-IRCCS, 94018 Troina, Italy.
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Matthews L, Narayanan T. High-resolution structural elucidation of extremely swollen lyotropic phases. J Colloid Interface Sci 2021; 610:359-367. [PMID: 34923273 DOI: 10.1016/j.jcis.2021.11.168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 11/27/2022]
Abstract
Self-assembled lyotropic phases are important in a variety of applications, in particular microemulsions are essential for formulation science. A spectacular situation arises when microemulsions are made to swell by systematically increasing the bending modulus of the surfactant film separating the oil and water regions. In an attempt to realize such extremely swollen microemulsion phases, Peter et al. [Phys. Rev. Lett., 76 (1996) 3866] found a variety of lyotropic phases including a long-range ordered three-dimensional cubic phase over a narrow section of the complex phase diagram of a pseudo-quaternary system composed of decane, brine, octanol, and sodium dodecyl sulfate. In this work, the same region of the phase diagram was reinvestigated using high-resolution small-angle X-ray scattering (HR-SAXS) and rheo-SAXS, which is an important technical aspect for homogenizing the sample and orienting the structural units. Whilst the formation of a swollen two-dimensional hexagonal phase was observed, the structural features of a cubic phase were not detected. The long correlation lengths noted prior were also seen here, over 2000 nm for the hexagonal phase, taken from rheo-SAXS measurements. Based on the measurements covering more than three orders of magnitude in scattering vector, the structure appeared to be an organization of elongated swollen emulsion droplets, which could form an interconnected structure, dense liquid-like order, or further order into a hexagonal morphology with unusually large lattice spacings for a surfactant system.
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Lee D, Minko T. Nanotherapeutics for Nose-to-Brain Drug Delivery: An Approach to Bypass the Blood Brain Barrier. Pharmaceutics 2021; 13:pharmaceutics13122049. [PMID: 34959331 PMCID: PMC8704573 DOI: 10.3390/pharmaceutics13122049] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 02/01/2023] Open
Abstract
Treatment of neurodegenerative diseases or other central nervous system (CNS) disorders has always been a significant challenge. The nature of the blood-brain barrier (BBB) limits the penetration of therapeutic molecules to the brain after oral or parenteral administration, which, in combination with hepatic metabolism and drug elimination and inactivation during its journey in the systemic circulation, decreases the efficacy of the treatment, requires high drug doses and often induces adverse side effects. Nose-to-brain drug delivery allows the direct transport of therapeutic molecules by bypassing the BBB and increases drug concentration in the brain. The present review describes mechanisms of nose-to-brain drug delivery and discusses recent advances in this area with especial emphasis on nanotechnology-based approaches.
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Affiliation(s)
- David Lee
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA;
| | - Tamara Minko
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA;
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA
- Environmental and Occupational Health Science Institute, Rutgers, The State University of New Jersey, 170 Frelinghuysen Road, Piscataway, NJ 08854, USA
- Correspondence: ; Tel.: +1-848-445-6348
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Quantification of microemulsion systems using low-field T 1-weighted imaging. Magn Reson Imaging 2021; 83:160-168. [PMID: 34391878 DOI: 10.1016/j.mri.2021.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/27/2021] [Accepted: 08/10/2021] [Indexed: 11/20/2022]
Abstract
Applied to Enhanced Oil Recovery, microemulsions are valuable systems for extracting the crude oil trapped by capillary forces in the porous reservoir rocks. The performances of the injected formulations are often assessed by quantifying oil composition in model systems that contain relatively high amount of surfactant/co-surfactant. Recently, the question of representativity of such systems was raised because kinetics aspects and complexity of crude were neglected in model systems and are likely to impact the process efficiency. The current quantification techniques limit the characterization of representative model systems as they are destructive, time consuming and not often applicable to dark or opaque systems. In the original aim to provide a quantitative kinetic study of such microemulsions, we propose a high resolution T1-weighted imaging technique to have access to 1D-composition profiles of co-surfactant, oil and brine in Winsor I, Winsor III and Winsor II microemulsions. The analysis is carried out on model systems at equilibrium for proof of concept. Results are correlated with X-Ray Micro-CT experiments to provide better interpretations and assess the method accuracy. We provide conditions of validity of the developed NMR method and discuss its potential limitations. To a larger extent, the method could be of interest to other applications that use similar systems.
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Mirzamani M, Dawn A, Aswal VK, Jones RL, Smith ED, Kumari H. Investigating the effect of a simplified perfume accord and dilution on the formation of mixed-surfactant microemulsions. RSC Adv 2021; 11:25858-25866. [PMID: 35479452 PMCID: PMC9037075 DOI: 10.1039/d1ra03458h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/29/2021] [Indexed: 02/03/2023] Open
Abstract
The phase analysis of a mixed surfactant system is much more complex than that for a single surfactant system. The addition of fragrance further enhances the complexity of such colloidal systems. The wide variation in structure and log P values of perfume raw materials influence its partitioning into the micellar phase. Herein, we have created a simplified perfume accord consisting of three perfume raw materials (3-PRM) and investigated its loading within a mixed-surfactant system consisting of sodium trideceth-2 sulfate/ST2S and cocamidopropyl betaine/CAPB, along with citric acid and dipropylene glycol. We performed a systematic phase diagram analysis and identified the isotropic phases and compositions of interest. Select compositions from the phase diagram were further investigated to learn how the geometry of the surfactant self-assembly and the localization of the PRMs within the surfactant self-assembly changed when water or perfume is added. A combined small-angle neutron scattering/SANS and NMR methodology was used to identify variation in colloidal domains and positioning of perfume molecules at varying dilutions/rinse off scenarios. The results obtained were utilized to better distinguish distorted micelles from true microemulsions. The systematic investigation here provides a fundamental understanding about the self-assembly, encapsulation and perfume release from a commercially relevant mixed surfactant system. Structural changes and phase analyses of a three-PRM accord in sodiumtrideceth-2 sulfate and cocamidopropyl betaine, citric acid and diproplylene glycol surfactant system as a function of dilution.![]()
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Affiliation(s)
- Marzieh Mirzamani
- James L. Winkle College of Pharmacy, University of Cincinnati 231 Albert Sabin Way, MSB 3109C Cincinnati OH 45267 USA
| | - Arnab Dawn
- James L. Winkle College of Pharmacy, University of Cincinnati 231 Albert Sabin Way, MSB 3109C Cincinnati OH 45267 USA
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Center Mumbai Maharashtra 400085 India
| | - Ronald L Jones
- NIST Center for Neutron Research, 100 Bureau Drive, National Institute of Standards and Technology Gaithersburg MD 20899 USA
| | - Ed D Smith
- Procter & Gamble Mason Montgomery Road Cincinnati OH 45040 USA
| | - Harshita Kumari
- James L. Winkle College of Pharmacy, University of Cincinnati 231 Albert Sabin Way, MSB 3109C Cincinnati OH 45267 USA
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Incorporation of Membrane Proteins Into Bicontinuous Microemulsions Through
Winsor‐III System‐Based
Extraction. J SURFACTANTS DETERG 2021. [DOI: 10.1002/jsde.12500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Luo L, Wu W, Sun D, Dai HB, Wang Y, Zhong Y, Wang JX, Maruf A, Nurhidayah D, Zhang XJ, Wang Y, Wang GX. Acid-Activated Melittin for Targeted and Safe Antitumor Therapy. Bioconjug Chem 2018; 29:2936-2944. [PMID: 30148623 DOI: 10.1021/acs.bioconjchem.8b00352] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Melittin (MLT), as a natural active biomolecule, can penetrate the tumor cell membrane to play a role in cancer treatment and will attract more attention in future development of antitumor drugs. The main component of natural bee venom MLT was modified by introducing a pH-sensitive amide bond between the 2,3-dimethyl maleimide (DMMA) and the lysine (Lys) of MLT (MLT-DMMA). MLT and its corresponding modified peptide MLT-DMMA were used for antitumor and biocompatibility validation. The biomaterial characteristics were tested by MALDI-TOF MS, 1H NMR, IUPAC and HPLC, cell viability, hemolytic and animal experiment safety evaluation. Compared with the primary melittin, the modified peptide showed decreased surface charge and low cytotoxicity in physiological conditions. Moreover, cell assays confirmed the acid-activated conversion of amide bond resulting in adequate safety during delivery and timely antitumor activity in tumor lesions. Thus, MLT-DMMA provided a feasible platform to improve the targeted and safe antitumor applications.
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Affiliation(s)
- Li Luo
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Wei Wu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Da Sun
- Institute of Life Sciences , Wenzhou University , Wenzhou 325000 , China
| | - Han-Bin Dai
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Yi Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Yuan Zhong
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Jin-Xuan Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Ali Maruf
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Deti Nurhidayah
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Xiao-Juan Zhang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
| | - Ying Wang
- Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment , Chongqing University Cancer Hospital , Chongqing , 400030 , China
| | - Gui-Xue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants , Bioengineering College of Chongqing University , Chongqing 400044 , China
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Hayes DG, Pingali SV, O'Neill HM, Urban VS, Ye R. Observation of a structural gradient in Winsor-III microemulsion systems. SOFT MATTER 2018; 14:5270-5276. [PMID: 29892769 DOI: 10.1039/c8sm00322j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We demonstrate here for the first time via small-angle neutron scattering (SANS) that the middle, bicontinuous microemulsion (BμE) phase of Winsor-III systems undergoes a gradual change of structure and composition in the vertical direction, contrary to the commonly held belief of uniform structure and composition. A vertical stage was deployed to enable precise alignment of a custom-designed rectangular cell containing the WIII system with respect to the neutron beam, allowing for several different vertical positions to be analyzed. For the water/AOT/CK-2,13 (two-tailed alkyl ethoxylate containing a 1,3-dioxolane linkage)/heptane Winsor-III system, the quasi-periodic repeat distance (d) and correlation length (ξ), obtained from the Teubner-Strey model applied to the SANS data, decreased and the surface area per volume of the surfactant monolayer (via Porod analysis) increased in the downward direction, trends that reflect an increase of surfactant concentration, consistent with the ultralow interfacial tension that often occurs for the lower liquid-liquid interface of many WIII systems. The water/sodium dodecyl sulfate (SDS)/1-pentanol/dodecane system shared the same trend with regard to d as observed for AOT/CK-2,13. In contrast, for SDS/pentanol, ξ increased and the amphiphilicity factor (fa) decreased in the downward direction, trends consistent with a decrease of cosurfactant (pentanol) concentration in the downward direction. Non-uniformity in the vertical direction has implications in the transport of solutes between WIII phases during the extractive purification of proteins or the removal of heavy metals and pollutants from wastewater, or the deposition of BμEs onto hydrophilic vs. hydrophobic surfaces as thin coatings.
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Affiliation(s)
- Douglas G Hayes
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996-4531, USA.
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