1
|
Denk P, Matthews L, Prévost S, Zemb T, Kunz W. A dilute nematic gel produced by intramicellar segregation of two polyoxyethylene alkyl ether carboxylic acids. J Colloid Interface Sci 2024; 659:833-848. [PMID: 38218087 DOI: 10.1016/j.jcis.2024.01.014] [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] [Received: 12/08/2023] [Revised: 12/28/2023] [Accepted: 01/03/2024] [Indexed: 01/15/2024]
Abstract
MOTIVATION Surfactants like C8E8CH2COOH have such bulky headgroups that they cannot show the common sphere-to-cylinder transition, while surfactants like C18:1E2CH2COOH are mimicking lipids and form only bilayers. Mixing these two types of surfactants allows one to investigate the competition between intramicellar segregation leading to disc-like bicelles and the temperature dependent curvature constraints imposed by the mismatch between heads and tails. EXPERIMENTS We establish phase diagrams as a function of temperature, surfactant mole ratio, and active matter content. We locate the isotropic liquid-isotropic liquid phase separation common to all nonionic surfactant systems, as well as nematic and lamellar phases. The stability and rheology of the nematic phase is investigated. Texture determination by polarizing microscopy allows us to distinguish between the different phases. Finally, SANS and SAXS give intermicellar distances as well as micellar sizes and shapes present for different compositions in the phase diagrams. FINDINGS In a defined mole ratio between the two components, intramicellar segregation wins and a viscoelastic discotic nematic phase is present at low temperature. Partial intramicellar mixing upon heating leads to disc growth and eventually to a pseudo-lamellar phase. Further heating leads to complete random mixing and an isotropic phase, showing the common liquid-liquid miscibility gap. This uncommon phase sequence, bicelles, lamellar phase, micelles, and water-poor packed micelles, is due to temperature induced mixing combined with dehydration of the headgroups. This general molecular mechanism explains also why a metastable water-poor lamellar phase quenched by cooling can be easily and reproducibly transformed into a nematic phase by gentle hand shaking at room temperature, as well as the entrapment of air bubbles of any size without encapsulation by bilayers or polymers.
Collapse
Affiliation(s)
- Patrick Denk
- Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Lauren Matthews
- ESRF - The European Synchrotron, 71 avenue des Martyrs, F-38043 Grenoble, France
| | - Sylvain Prévost
- ESRF - The European Synchrotron, 71 avenue des Martyrs, F-38043 Grenoble, France; Institut Laue-Langevin - The European Neutron Source, 71 avenue des Martyrs, F-38042 Grenoble, France
| | - Thomas Zemb
- Institut de Chimie Séparative de Marcoule, BP 17171, F-30207 Bagnols sur Cèze, France
| | - Werner Kunz
- Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93053 Regensburg, Germany.
| |
Collapse
|
2
|
Consuelo-Leal A, Araujo-Ferreira AG, Lucas-Oliveira E, Bonagamba TJ, Auccaise R. NMR Relaxation by Redfield equation in a spin system I=7/2. J Magn Reson 2023; 349:107403. [PMID: 36863304 DOI: 10.1016/j.jmr.2023.107403] [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] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 06/19/2023]
Abstract
The Redfield master equation was solved analytically for a nuclear system with spin I=7/2. Using the irreducible tensor operator basis, the solutions of each density matrix element were computed. The experimental setup consisted of the 133Cs nuclei of the cesium-pentadecafluorooctanoate molecule in a lyotropic liquid crystal sample in the nematic phase at room temperature. Experimental longitudinal and transverse magnetization dynamics of the 133Cs nuclei were monitored, and the theoretical approach was used to generate valuable mathematical expressions with the highest accuracy through numerical procedures. This methodology can be extended to other nuclei with minimal difficulties.
Collapse
Affiliation(s)
- A Consuelo-Leal
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil.
| | - A G Araujo-Ferreira
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil
| | - E Lucas-Oliveira
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil
| | - T J Bonagamba
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, São Paulo, Brazil
| | - R Auccaise
- Departamento de Física, Universidade Estadual de Ponta Grossa, Av. General Carlos Cavalcanti 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
| |
Collapse
|
3
|
de Araujo GRS, Azevedo Lima OV, Barreto Neujahr JP, Matos SS, de Souza TA, Dos Santos AM, Chorilli M, de Souza Araujo AA, Duarte MC, da Cunha Gonsalves JKM, de Souza Nunes R, Dos Santos MRV, Vitorino Sarmento VH, Moreira Lira AA. Lyotropic liquid crystal mesophases as transdermal delivery systems for lipophilic drugs: A comparative study. Int J Pharm 2023; 636:122853. [PMID: 36931537 DOI: 10.1016/j.ijpharm.2023.122853] [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] [Received: 10/05/2022] [Revised: 03/10/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023]
Abstract
The present work aimed to evaluate different Liquid Crystal Mesophases (LCM) as transdermal drug delivery systems (TDDS) for nifedipine (NFD), a lipophilic drug model. The formulations composed of water, Citrus sinensis essential oil (CSEO), PPG-5-CETETH-20, and Olive oil ester PEG-7 were obtained and characterized by polarized light microscopy (PLM), rheology, small-angle x-ray scattering (SAXS), Fourier transform infrared coupled with an attenuated total reflection accessory (FTIR-ATR) and in vitro assays: bioadhesion, drug release, skin permeation, and retention tests. As a result, changes in component proportions led to several transparent viscous systems with an anisotropic profile. PLM and SAXS proved the presence of lamellar (S1), hexagonal (S3), and lamellar + hexagonal (S2) LCM, and rheology showed a high viscoelasticity profile. LCMs were able to adhere to the skin, and S2 achieved higher adhesion strength. NFD (5 mg/mL) has not modified the organization of LCMs. Results also showed that S3 promoted higher permeation and retention and higher disorganization of stratum corneum lipids, which is the main permeation-enhancing mechanism. Thus, the formulations obtained can carry and improve drug delivery through the skin and are promising TDDS for lipophilic drug administration, such as NFD.
Collapse
Affiliation(s)
| | | | | | - Saulo Santos Matos
- Department of Pharmacy, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Thalisson Amorim de Souza
- Institute for Research in Pharmaceutical and Medications, Federal University of Paraíba, João Pessoa, PB, Brazil
| | | | - Marlus Chorilli
- School of Pharmaceutical Sciences, Paulista State University, Araraquara, SP, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
4
|
Rajesh S, Zhai J, Drummond CJ, Tran N. Synthetic ionizable aminolipids induce a pH dependent inverse hexagonal to bicontinuous cubic lyotropic liquid crystalline phase transition in monoolein nanoparticles. J Colloid Interface Sci 2020; 589:85-95. [PMID: 33450463 DOI: 10.1016/j.jcis.2020.12.060] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [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: 08/31/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 01/28/2023]
Abstract
A prospective class of materials for drug delivery is lyotropic liquid crystalline (LLC) nanoparticles, such as cubosomes and hexosomes. Efforts are being made to generate a pH dependent system, which exhibits slow release hexosomes (H2) at physiological pH and relatively fast release cubosomes (Q2) at acidic disease sites such as in various cancers and bacterial infection (pH ~ 5.5-6.5). Herein, we report the synthesis of nine ionizable aminolipids, which were doped into monoolein (MO) lipid nanoparticles. Using high throughput formulation and synchrotron small angle X-ray scattering (SAXS), the effects of aminolipid structure and concentration on the mesophase of MO nanoparticles at various pHs were determined. As the pH changed from neutral to acidic, mesophases, could be formed in an order L2 (inverse micelles) → H2 → Q2. Specifically, systems with heterocyclic oleates exhibited the H2 to Q2 transition at pH 5.5-6.5. Furthermore, the phase transition pH could be fine-tuned by incorporating two aminolipids into the nanoparticles. Nanoparticles with a pH dependent phase transition as described in this study may be useful as drug delivery carriers for the treatment of cancers and certain bacterial infection.
Collapse
Affiliation(s)
- Sarigama Rajesh
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3000, Australia
| | - Jiali Zhai
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3000, Australia
| | - Calum J Drummond
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3000, Australia.
| | - Nhiem Tran
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3000, Australia.
| |
Collapse
|
5
|
Ramirez G, Pham AC, Clulow AJ, Salim M, Hawley A, Boyd BJ. Sustained absorption of delamanid from lipid-based formulations as a path to reduced frequency of administration. Drug Deliv Transl Res 2021; 11:1236-44. [PMID: 32935235 DOI: 10.1007/s13346-020-00851-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2020] [Indexed: 11/18/2022]
Abstract
Delamanid is a poorly water-soluble drug currently being used for the treatment of tuberculosis. The high frequency of dosing leads to poor adherence for patients who live in lower economic and nomadic populations. Non-digestible self-assembling lipids as a formulation approach for poorly water-soluble drugs have previously been shown to extend the window of absorption through gastric retention. We hypothesise that this approach could lead to the reduction of dosing frequency for delamanid and thereby has potential to improve adherence. Formulations of delamanid were prepared in selachyl alcohol and phytantriol as non-digestible self-assembling lipid vehicles, and their behaviour was compared with reconstituted milk powder, as a digestible lipid-based formulation, and an aqueous suspension. The self-assembly of selachyl alcohol and phytantriol in aqueous media in the presence of delamanid was studied using small angle X-ray scattering and produced the inverse hexagonal (H2) and inverse bicontinuous cubic (V2) liquid crystal structures, respectively. The times at which maximum delamanid levels in plasma were observed (Tmax) after oral administration of the phytantriol, selachyl alcohol and reconstituted milk powder formulations of delamanid to rats were 27 ± 3, 20 ± 4 and 6.5 ± 1.0 h, respectively, compared with the aqueous suspension formulation with a Tmax of 3.4 ± 1 h, which confirms the hypothesis of an extended duration of absorption after administration in non-digestible self-assembling lipids. The digestion products of the triglycerides in the milk formulation increased the solubilisation of delamanid in the gastrointestinal tract, leading to an increase in exposure compared with the aqueous suspension formulation but did not significantly extend Tmax. Overall, the non-digestible nanostructured lipid formulations extended the duration of absorption of delamanid well beyond that from milk or suspension formulations. Graphical abstract ![]()
Collapse
|
6
|
Fan Y, Chen H, Huang Z, Zhu J, Wan F, Peng T, Pan X, Huang Y, Wu C. Taste-masking and colloidal-stable cubosomes loaded with Cefpodoxime proxetil for pediatric oral delivery. Int J Pharm 2020; 575:118875. [PMID: 31765781 DOI: 10.1016/j.ijpharm.2019.118875] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/06/2019] [Accepted: 11/12/2019] [Indexed: 11/18/2022]
Abstract
Drug administration failure has been often witnessed in pediatric due to children's resistance to take medicines with bitter taste. Taste-masking is the key requirement among the scanty drugs available for children. Solid taste-masking systems, such as tablets and capsules, are difficult to swallow for children. Therefore, a liquid taste-masking system based on lyotropic liquid crystalline nanoparticles (LLCNs) was developed in this study. Cefpodoxime proxetil (CFP), a typically bitter drug used as antibiotic in pediatric, was selected as the model drug, and the encapsulation of CFP into the LLCNs was envisaged to improve their taste. Pluronic F127 was added to improve the colloidal stability of CFP-LLCNs. The optimized CFP-LLCNs showed the particle size of 187.29 ± 4.12 nm and the encapsulation efficiency of 85.80%. The mesophase analysis by polarized light microscopy and small angle X-ray scattering confirmed the cubic phase of CFP-LLCNs. It showed a sustained-release profile well fitted to Higuchi model, indicating that diffusion and erosion were both responsible for the CFP release. The taste-masking ability of CFP-LLCNs was confirmed by electronic tongue, compared to CFP and commercial product. The colloidal stability was verified after 3 months storage in room condition (25 ± 2 °C, 70 ± 2%RH). To sum up, the taste-masking and colloidal-stable CFP-LLCNs showed great potential for pediatric oral delivery.
Collapse
Affiliation(s)
- Yanliang Fan
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, Guangdong, PR China.
| | - Hsinyi Chen
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, Guangdong, PR China
| | - Zhengwei Huang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, Guangdong, PR China.
| | - Jianzheng Zhu
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, Guangdong, PR China
| | - Faiiam Wan
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, Guangdong, PR China
| | - Tingting Peng
- College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, PR China
| | - Xin Pan
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, Guangdong, PR China.
| | - Ying Huang
- College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, PR China.
| | - Chuanbin Wu
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, Guangdong, PR China.
| |
Collapse
|
7
|
Liu Q, Graham B, Hawley A, Dong YD, Boyd BJ. Novel agrochemical conjugates with self-assembling behaviour. J Colloid Interface Sci 2018; 512:369-378. [PMID: 29096098 DOI: 10.1016/j.jcis.2017.10.070] [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] [Received: 09/02/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 11/29/2022]
Abstract
HYPOTHESIS That conjugation of agrichemicals to pro-assembly hydrophobic moieties will enable enhanced compatibility and loading with host lyotropic liquid crystalline carrier matrix, and potentially self-assemble in their own right in aqueous environments. EXPERIMENTS A series of lipid-like agrochemical-conjugates were synthesized using specific amphiphilic entities conjugated onto the agrochemicals, picloram and 2,4-dichlorophenoxyacetic acid (2,4-D). The self-assembly behaviour and compatibility of the novel entities when incorporated into phytantriol and monoolein-based liquid crystalline systems were examined using small angle X-ray scattering, cryo-TEM and polarized optical microscopy. FINDINGS Compared to agrochemical-conjugates with simple alkyl ester groups, the esterification of the agrochemicals with amphiphilic groups such as phytantriol and monoolein led to greater structural compatibility and consequently a greater loading of the agrochemicals in the liquid crystalline systems without destabilizing phase structure. Picloram-monoolein and picloram-monoelaidin can self-assemble to form lamellar structures in water. However, certain agrochemical-conjugates such as picloram-monoelaidin and picloram-PEGn-oleate showed poor compatibility with liquid crystalline systems, resulting in phase separation.
Collapse
Affiliation(s)
- Qingtao Liu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Bim Graham
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Adrian Hawley
- SAXS/WAXS Beamline, Australian Synchrotron, Clayton, VIC, Australia
| | - Yao-Da Dong
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Ben J Boyd
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC 3052, Australia.
| |
Collapse
|
8
|
Mei L, Xie Y, Huang Y, Wang B, Chen J, Quan G, Pan X, Liu H, Wang L, Liu X, Wu C. Injectable in situ forming gel based on lyotropic liquid crystal for persistent postoperative analgesia. Acta Biomater 2018; 67:99-110. [PMID: 29225151 DOI: 10.1016/j.actbio.2017.11.057] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 11/21/2017] [Accepted: 11/30/2017] [Indexed: 12/15/2022]
Abstract
Local anesthetics have been widely used for postoperative analgesia. However, multiple injections or local infiltration is required due to the short half-lives of local anesthetics after single injection, which results in poor compliance and increasing medical expense. In this study, an in situ forming gel (ISFG) based on lyotropic liquid crystal was developed to deliver bupivacaine hydrochloride (BUP) for long-acting postoperative analgesia. BUP-ISFG was designed to be administrated as a precursor solution which would spontaneously transform into gel with well-defined internal nanostructures for sustained drug release at the site of administration when exposed to physiological fluid. A lamellar-hexagonal-cubic phase transition occurred during the in situ gelation. The lamellar phase of the precursor solution endows it with low viscosity for good syringeability while the unique nanostructures of hexagonal and cubic phases of the in situ gel provide sustained drug release. Persistent analgesia effect in vivo was achieved with BUP-ISFG, and the plasma BUP concentration was found to be steadier compared to commercially available BUP for injection. In addition, the ISFG displayed acceptable biocompatibility and good biodegradability. The findings are positive about ISFG as a sustained release system for persistent postoperative analgesia. STATEMENT OF SIGNIFICANCE To address the issue of insufficient postoperative analgesia associated with short half-lives of local anesthetics after single injection, an in situ forming gel (ISFG) based on lyotropic liquid crystal was developed to deliver bupivacaine hydrochloride (BUP) for postoperative analgesia over three days. The results demonstrated that persistent analgesia effect in vivo was achieved with single injection of BUP-ISFG, and the plasma BUP concentration was found to be steadier compared to commercially available BUP injection. The BUP-ISFG possessed a lamellar-hexagonal-cubic phase transition with corresponding crystal change in 3D nanostructure during the in situ gelation. The relationship between crystal nanostructure and carrier function, might provide some insights to the design and clinical applications of the drug delivery systems based on lyotropic liquid crystal.
Collapse
|
9
|
Lee JS, Regatte RR, Jerschow A. Magnetization transfer in a partly deuterated lyotropic liquid crystal by single- and dual-frequency RF irradiations. J Magn Reson 2017; 281:141-150. [PMID: 28595121 PMCID: PMC5537047 DOI: 10.1016/j.jmr.2017.05.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 05/26/2017] [Accepted: 05/29/2017] [Indexed: 05/08/2023]
Abstract
The mechanism of magnetization transfer (MT) in a lyotropic liquid crystal made of sodium dodecyl sulfate, decanol, and water molecules is investigated by using deuterated molecules and single- and dual-frequency RF irradiations. The resulting Z-spectra suggest that the decanol molecules are mainly responsible for the MT effects in this system, through proton exchange to water. This is further confirmed by monitoring the relaxation of dipolar order, which allows one to estimate the transfer rate of magnetization from decanol to water. The potential benefits of using dual-frequency RF irradiation for inducing MT effects are explored through numerical solutions to a MT model based on Provotorov's partial saturation theory.
Collapse
Affiliation(s)
- Jae-Seung Lee
- Department of Radiology, New York University Langone Medical Center, New York, NY 10016, USA; Department of Chemistry, New York University, New York, NY 10003, USA.
| | - Ravinder R Regatte
- Department of Radiology, New York University Langone Medical Center, New York, NY 10016, USA
| | - Alexej Jerschow
- Department of Chemistry, New York University, New York, NY 10003, USA
| |
Collapse
|
10
|
Frusawa H, Yoshii G. Anisotropic micro-cloths fabricated from DNA-stabilized carbon nanotubes: one-stop manufacturing with electrode needles. Nanoscale Res Lett 2015; 10:107. [PMID: 25852402 PMCID: PMC4385237 DOI: 10.1186/s11671-015-0817-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 02/12/2015] [Indexed: 05/16/2023]
Abstract
Among a variety of solution-based approaches to fabricate anisotropic films of aligned carbon nanotubes (CNTs), we focus on the dielectrophoretic assembly method using AC electric fields in DNA-stabilized CNT suspensions. We demonstrate that a one-stop manufacturing system using electrode needles can draw anisotropic DNA-CNT hybrid films of 10 to 100 µm in size (i.e., free-standing DNA-CNT micro-cloths) from the remaining suspension into the atmosphere while maintaining structural order. It has been found that a maximal degree of polarization (ca. 40%) can be achieved by micro-cloths fabricated from a variety of DNA-CNT mixtures. Our results suggest that the one-stop method can impart biocompatibility to the downsized CNT films and that the DNA-stabilized CNT micro-cloths directly connected to an electrode could be useful for biofuel cells in terms of electron transfer and/or enzymatic activity.
Collapse
Affiliation(s)
- Hiroshi Frusawa
- Institute for Nanotechnology, Kochi University of Technology, Tosa-Yamada, 782-8502 Kochi Japan
| | - Gen Yoshii
- Institute for Nanotechnology, Kochi University of Technology, Tosa-Yamada, 782-8502 Kochi Japan
| |
Collapse
|
11
|
Albayrak C, Barım G, Dag Ö. Effect of hygroscopicity of the metal salt on the formation and air stability of lyotropic liquid crystalline mesophases in hydrated salt-surfactant systems. J Colloid Interface Sci 2014; 433:26-33. [PMID: 25112909 DOI: 10.1016/j.jcis.2014.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 05/01/2014] [Revised: 07/04/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
Abstract
It is known that alkali, transition metal and lanthanide salts can form lyotropic liquid crystalline (LLC) mesophases with non-ionic surfactants (such as CiH2i+1(OCH2CH2)jOH, denoted as CiEj). Here we combine several salt systems and show that the percent deliquescence relative humidity (%DRH) value of a salt is the determining parameter in the formation and stability of the mesophases and that the other parameters are secondary and less significant. Accordingly, salts can be divided into 3 categories: Type I salts (such as LiCl, LiBr, LiI, LiNO3, LiClO4, CaCl2, Ca(NO3)2, MgCl2, and some transition metal nitrates) have low %DRH and form stable salt-surfactant LLC mesophases in the presence of a small amount of water, type II salts (such as some sodium and potassium salts) that are moderately hygroscopic form disordered stable mesophases, and type III salts that have high %DRH values, do not form stable LLC mesophases and leach out salt crystals. To illustrate this effect, a large group of salts from alkali and alkaline earth metals were investigated using XRD, POM, FTIR, and Raman techniques. Among the different salts investigated in this study, the LiX (where X is Cl(-), Br(-), I(-), NO3(-), and ClO4(-)) and CaX2 (X is Cl(-), and NO3(-)) salts were more prone to establish LLC mesophases because of their lower %DRH values. The phase behavior with respect to concentration, stability, and thermal behavior of Li(I) systems were investigated further. It is seen that the phase transitions among different anions in the Li(I) systems follow the Hofmeister series.
Collapse
Affiliation(s)
- Cemal Albayrak
- Bilkent University, Department of Chemistry, 06800 Ankara, Turkey
| | - Gözde Barım
- Bilkent University, Department of Chemistry, 06800 Ankara, Turkey
| | - Ömer Dag
- Bilkent University, Department of Chemistry, 06800 Ankara, Turkey.
| |
Collapse
|
12
|
Martiel I, Sagalowicz L, Mezzenga R. Phospholipid-based nonlamellar mesophases for delivery systems: bridging the gap between empirical and rational design. Adv Colloid Interface Sci 2014; 209:127-43. [PMID: 24685272 DOI: 10.1016/j.cis.2014.03.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 03/07/2014] [Accepted: 03/07/2014] [Indexed: 11/28/2022]
Abstract
Phospholipids are ubiquitous cell membrane components and relatively well-accepted ingredients due to their natural origin. Phosphatidylcholine (PC) in particular offers a promising alternative to monoglycerides for lyotropic liquid crystalline (LLC) delivery system applications in the food, cosmetics and pharmaceutical industries, provided its strong tendency to form zero-mean curvature lamellar mesophases in water can be overcome. Higher negative curvatures are usually reached through the addition of a third lipid component, forming a ternary diagram phospholipid/water/oil. The initial part of this work summarizes the potential advantages and the challenges of phospholipid-based delivery system applications. In the next part, various ternary PC/water/oil systems are discussed, with a special emphasis on the PC/water/cyclohexane and PC/water/α-tocopherol systems. We report that R-(+)-limonene has a quantitatively similar effect as cyclohexane. The last part is devoted to the theoretical interpretation of the observed phase behaviors. A fruitful parallel is drawn with PC polymer-like reverse micelles, leading to a thermodynamic description in terms of interfacial bending energy. Investigations at the molecular level are reviewed to help in bridging the empirical and theoretical approaches. Predictive rules are finally derived from this wide-ranging overview, thereby opening the way to a future rational design of PC-based LLC delivery systems.
Collapse
Affiliation(s)
- Isabelle Martiel
- Food and Soft Materials Science, Institute of Food, Nutrition & Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zurich, Switzerland
| | - Laurent Sagalowicz
- Nestlé Research Center, Vers-Chez-Les-Blanc, CH-1000 Lausanne 26, Switzerland
| | - Raffaele Mezzenga
- Food and Soft Materials Science, Institute of Food, Nutrition & Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zurich, Switzerland.
| |
Collapse
|