1
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Mayorga LS, Masone D. The Secret Ballet Inside Multivesicular Bodies. ACS NANO 2024; 18:15651-15660. [PMID: 38830824 DOI: 10.1021/acsnano.4c01590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Lipid bilayers possess the capacity for self-assembly due to the amphipathic nature of lipid molecules, which have both hydrophobic and hydrophilic regions. When confined, lipid bilayers exhibit astonishing versatility in their forms, adopting diverse shapes that are challenging to observe through experimental means. Exploiting this adaptability, lipid structures motivate the development of bio-inspired mechanomaterials and integrated nanobio-interfaces that could seamlessly merge with biological entities, ultimately bridging the gap between synthetic and biological systems. In this work, we demonstrate how, in numerical simulations of multivesicular bodies, a fascinating evolution unfolds from an initial semblance of order toward states of higher entropy over time. We observe dynamic rearrangements in confined vesicles that reveal unexpected limit shapes of distinct geometric patterns. We identify five structures as the basic building blocks that systematically repeat under various conditions of size and composition. Moreover, we observe more complex and less frequent shapes that emerge in confined spaces. Our results provide insights into the dynamics of multivesicular systems, offering a richer understanding of how confined lipid bodies spontaneously self-organize.
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Affiliation(s)
- Luis S Mayorga
- Instituto de Histología y Embriología de Mendoza (IHEM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCuyo), 5500 Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), 5500, Mendoza, Argentina
| | - Diego Masone
- Instituto de Histología y Embriología de Mendoza (IHEM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCuyo), 5500 Mendoza, Argentina
- Facultad de Ingeniería, Universidad Nacional de Cuyo (UNCuyo), 5500 Mendoza, Argentina
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2
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Bernardi M, Vernizzi M, Baraldi L, Balog S, Bassanetti I, Sgarbi E, Fornasari L, Arrigoni C, Cardarelli F. Phasor-FLIM-guided unraveling of ATRA supramolecular organization in liposomal nanoformulations. NANOSCALE 2023; 15:19085-19090. [PMID: 37991853 DOI: 10.1039/d3nr03420h] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
Here we use fluorescence lifetime imaging microscopy (FLIM) to study the supramolecular organization of nanoencapsulated liposomal all-trans retinoic acid (ATRA), exploiting ATRA's intrinsic fluorescence as a source of signal and phasor transformation as a fit-free analytical approach to lifetime data. Our non-invasive method is suitable for checking for the presence of a fraction of ATRA molecules interacting with liposomal membranes. The results are validated by independent small-angle X-ray scattering (SAXS) and nano-differential scanning calorimetry (NanoDSC) measurements, probing ATRA's putative position on the membrane and effect on membrane organization. Besides the insights on the specific case-study proposed, the present results confirm the effectiveness of Phasor-FLIM analysis in elucidating the nanoscale supramolecular organization of fluorescent drugs in pharmaceutical formulations. This underscores the importance of leveraging advanced imaging techniques to deepen our understanding and optimize drugs' performance in delivery applications.
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Affiliation(s)
- Mario Bernardi
- Laboratorio NEST, Scuola Normale Superiore, Pisa, Italy.
| | | | - Laura Baraldi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università di Parma, 43124 Parma, Italy
| | - Sandor Balog
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
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3
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Prabhu J, Singh AP, Vanni S. An in silico osmotic pressure approach allows characterization of pressure-area isotherms of lipid monolayers at low molecular areas. SOFT MATTER 2023; 19:3377-3385. [PMID: 37102755 PMCID: PMC10170484 DOI: 10.1039/d2sm01419j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Surface pressure-area isotherms of lipid monolayers at the air-water interface provide essential information about the structure and mechanical behaviour of lipid membranes. These curves can be readily obtained through Langmuir trough measurements and, as such, have been collected for decades in the field of membrane biochemistry. However, it is still challenging to directly observe and understand nanoscopic features of monolayers through such experiments, and molecular dynamics (MD) simulations are generally used to provide a molecular view of such interfaces. In MD simulations, the surface pressure-area (Π-A) isotherms are generally computed using the Kirkwood-Irving formula, that relies on the evaluation of the pressure tensor. This approach, however, has intrinsic limitations when the molecular area in the monolayer is low (typically < 60 Å2 per lipid). Recently, an alternative method to compute Π-A isotherms of surfactants, based on the calculation of the three-dimensional osmotic pressure via the implementation of semipermeable barriers was proposed. In this work, we investigate the feasibility of this approach for long-chain surfactants such as phospholipids. We identify some discrepancies between the computed values and experimental results, and we propose a semi-empirical correction based on the molecular structure of the surfactants at the monolayer interface. To validate the potential of this new approach, we simulate several phosphatidylcholine and phosphatidylethanolamine lipids at various temperatures using all-atom and coarse-grained force fields, and we compute the corresponding Π-A isotherms. Our results show that the Π-A isotherms obtained using the new method are in very good agreement with experiments and far superior to the canonical pressure tensor-based method at low molecular areas. This corrected osmotic pressure method allows for accurate characterization of the molecular packing in monolayers in various physical phases.
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Affiliation(s)
- Janak Prabhu
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
| | - Akhil Pratap Singh
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
| | - Stefano Vanni
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
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4
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Interaction of guanidinium and ammonium cations with phosphatidylcholine and phosphatidylserine lipid bilayers - Calorimetric, spectroscopic and molecular dynamics simulations study. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184122. [PMID: 36739930 DOI: 10.1016/j.bbamem.2023.184122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/10/2023] [Accepted: 01/24/2023] [Indexed: 02/05/2023]
Abstract
The ability of arginine-rich peptides to cross the lipid bilayer and enter cytoplasm, unlike their lysine-based analogues, is intensively studied in the context of cell-penetrating peptides. Although the experiments have not yet reconstructed their internalization mechanism, the computational studies have shown that the type or charge of lipid polar groups is one of the crucial factors in their translocation. In order to gain more detailed insight into the interaction of guanidinium (Gdm+) and ammonium (NH4+) cations, as important building blocks in arginine and lysine amino acids, with lipid bilayers, we conducted the experimental and computational study that tackles this phenomenon. The adsorption of Gdm+ and NH4+ on lipid bilayers prepared from a zwitterionic (DPPC) and an anionic (DPPS) lipid was examined by thermoanalytic and spectroscopic techniques. Using temperature-dependent UV-Vis spectroscopy and DSC calorimetry we determined the impact of Gdm+ and NH4+ on the thermotropic properties of lipid bilayers. FTIR data, along with molecular dynamics simulations, unraveled the molecular-level details on the nature of their interactions, showing the proton transfer between NH4+ and DPPS, but not between Gdm+ and DPPS. The findings originated from this work imply that Gdm+ and NH4+ form qualitatively different interactions with lipids of different charge which is reflected in the physico-chemical interactions that arginine-and lysine-based peptides establish at a complex and chemically heterogeneous environment such as the biological membrane.
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5
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Recent Preclinical and Clinical Progress in Liposomal Doxorubicin. Pharmaceutics 2023; 15:pharmaceutics15030893. [PMID: 36986754 PMCID: PMC10054554 DOI: 10.3390/pharmaceutics15030893] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/03/2023] [Accepted: 03/08/2023] [Indexed: 03/12/2023] Open
Abstract
Doxorubicin (DOX) is a potent anti-cancer agent that has garnered great interest in research due to its high efficacy despite dose-limiting toxicities. Several strategies have been exploited to enhance the efficacy and safety profile of DOX. Liposomes are the most established approach. Despite the improvement in safety properties of liposomal encapsulated DOX (in Doxil and Myocet), the efficacy is not superior to conventional DOX. Functionalized (targeted) liposomes present a more effective system to deliver DOX to the tumor. Moreover, encapsulation of DOX in pH-sensitive liposomes (PSLs) or thermo-sensitive liposomes (TSLs) combined with local heating has improved DOX accumulation in the tumor. Lyso-thermosensitive liposomal DOX (LTLD), MM-302, and C225-immunoliposomal(IL)-DOX have reached clinical trials. Further functionalized PEGylated liposomal DOX (PLD), TSLs, and PSLs have been developed and evaluated in preclinical models. Most of these formulations improved the anti-tumor activity compared to the currently available liposomal DOX. However, the fast clearance, the optimization of ligand density, stability, and release rate need more investigations. Therefore, we reviewed the latest approaches applied to deliver DOX more efficiently to the tumor, preserving the benefits obtained from FDA-approved liposomes.
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6
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Guillot AJ, Martínez-Navarrete M, Garrigues TM, Melero A. Skin drug delivery using lipid vesicles: A starting guideline for their development. J Control Release 2023; 355:624-654. [PMID: 36775245 DOI: 10.1016/j.jconrel.2023.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 02/14/2023]
Abstract
Lipid vesicles can provide a cost-effective enhancement of skin drug absorption when vesicle production process is optimised. It is an important challenge to design the ideal vesicle, since their properties and features are related, as changes in one affect the others. Here, we review the main components, preparation and characterization methods commonly used, and the key properties that lead to highly efficient vesicles for transdermal drug delivery purposes. We stand by size, deformability degree and drug loading, as the most important vesicle features that determine the further transdermal drug absorption. The interest in this technology is increasing, as demonstrated by the exponential growth of publications on the topic. Although long-term preservation and scalability issues have limited the commercialization of lipid vesicle products, freeze-drying and modern escalation methods overcome these difficulties, thus predicting a higher use of these technologies in the market and clinical practice.
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Affiliation(s)
- Antonio José Guillot
- Department of Pharmacy and Pharmaceutical Technology and Parasitology, University of Valencia, Avda. Vicente A. Estelles SN, Burjassot (Valencia), Spain
| | - Miquel Martínez-Navarrete
- Department of Pharmacy and Pharmaceutical Technology and Parasitology, University of Valencia, Avda. Vicente A. Estelles SN, Burjassot (Valencia), Spain
| | - Teresa M Garrigues
- Department of Pharmacy and Pharmaceutical Technology and Parasitology, University of Valencia, Avda. Vicente A. Estelles SN, Burjassot (Valencia), Spain
| | - Ana Melero
- Department of Pharmacy and Pharmaceutical Technology and Parasitology, University of Valencia, Avda. Vicente A. Estelles SN, Burjassot (Valencia), Spain.
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7
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Maleš P, Butumović M, Erceg I, Brkljača Z, Bakarić D. Influence of DPPE surface undulations on melting temperature determination: UV/Vis spectroscopic and MD study. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184072. [PMID: 36216096 DOI: 10.1016/j.bbamem.2022.184072] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 09/09/2022] [Accepted: 10/04/2022] [Indexed: 11/13/2022]
Abstract
One of the most distinguished quantities that describes lipid main phase transition, i.e. the transition from the gel (Lβ(')) to the fluid (Lα) phase, is its melting temperature (Tm). Because melting is accompanied by a large change in enthalpy the, Lβ(') → Lα transition can be monitored by various calorimetric, structural and spectroscopic techniques and Tm should be the same regardless of the metric monitored or the technique employed. However, in the case of DPPE multilamellar aggregates there is a small but systematic deviation of Tm values determined by DSC and FTIR spectroscopy. The aim of this paper is to explain this discrepancy by combined UV/Vis spectroscopic and MD computational approach. Multivariate analysis performed on temperature-dependent UV/Vis spectra of DPPE suspensions demonstrated that at 55 ± 1 °C certain phenomenon causes a small but detectable change in suspension turbidity, whereas a dominant change in the latter is registered at 63.2 ± 0.4 °C that coincides with Tm value determined from DSC curve. If this effect should be ignored, the overall data give Tm value the same as FTIR spectra data (61.0 ± 0.4 °C). As the classical MD simulations suggest that about 10° below Tm certain undulations appear at the surface of DPPE bilayers, we concluded that certain discontinuities in curvature fluctuations arise at reported temperature which are to some extent coupled with lipid melting. Ultimately, such events and the associated changes in curvature affect Tm value measured by different techniques.
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Affiliation(s)
- Petra Maleš
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Marija Butumović
- Division of Analytical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
| | - Ina Erceg
- Division for Physical Chemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Zlatko Brkljača
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
| | - Danijela Bakarić
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
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8
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Veloso SRS, Gomes V, Mendes SLF, Hilliou L, Pereira RB, Pereira DM, Coutinho PJG, Ferreira PMT, Correa-Duarte MA, Castanheira EMS. Plasmonic lipogels: driving co-assembly of composites with peptide-based gels for controlled drug release. SOFT MATTER 2022; 18:8384-8397. [PMID: 36193825 DOI: 10.1039/d2sm00926a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Supramolecular short peptide-based gels are promising materials for the controlled release of drugs (e.g. chemotherapeutic drugs) owing to the biocompatibility and similarity to cell matrix. However, the drug encapsulation and control over its release, mainly the hydrophilic drugs, can be a cumbersome task. This can be overcome through encapsulation/compartmentalization of drugs in liposomes, which can also enable spatiotemporal control and enhanced drug release through a trigger, such as photothermia. Having this in mind, we explored the assembly of silica-coated gold nanoparticles and liposomes (storage units) with dehydropeptide-based hydrogels as a proof-of-concept to afford peptide-based NIR light-responsive lipogels. Several liposomes compositions were assessed that displayed influence on the final assembly properties by combining with silica-coated gold nanorods (∼106 nm). Gold nanospheres (∼11 nm) were used to study the preparation method, which revealed the importance of initially combine liposomes with nanoparticles and then the gelator solution to achieve a closer proximity of the nanoparticles to the liposomes. The control over a hydrophilic model drug, 5(6)-carboxyfluorescein, was only achieved by its encapsulation in liposomes, in which the presence of silica-coated nanorods further enabled the use of photothermia to induce the liposomes phase transition and stimulate the drug release. Further, both composites, the liposomes and silica-coated gold nanorods, induced a lower elastic modulus, but also provided an enhanced gelation kinetics. Hereby, this work advances fabrication strategies for the development of short peptide-based hydrogels towards on-demand, sustained and controlled release of hydrophilic drugs through photothermia under NIR light irradiation.
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Affiliation(s)
- Sérgio R S Veloso
- Physics Centre of Minho and Porto Universities (CF-UM-UP) and LaPMET Associate Laboratory, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Valéria Gomes
- Physics Centre of Minho and Porto Universities (CF-UM-UP) and LaPMET Associate Laboratory, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
- Centre of Chemistry (CQUM), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Sérgio L F Mendes
- Physics Centre of Minho and Porto Universities (CF-UM-UP) and LaPMET Associate Laboratory, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Loic Hilliou
- Institute for Polymers and Composites, Department of Polymer Engineering, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal
| | - Renato B Pereira
- REQUIMTE/LAQV, Laboratory of Pharmacognosy, Department of Chemistry, Faculty of Pharmacy, University of Porto, R. Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - David M Pereira
- REQUIMTE/LAQV, Laboratory of Pharmacognosy, Department of Chemistry, Faculty of Pharmacy, University of Porto, R. Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Paulo J G Coutinho
- Physics Centre of Minho and Porto Universities (CF-UM-UP) and LaPMET Associate Laboratory, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Paula M T Ferreira
- Centre of Chemistry (CQUM), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | | | - Elisabete M S Castanheira
- Physics Centre of Minho and Porto Universities (CF-UM-UP) and LaPMET Associate Laboratory, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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9
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Maleš P, Pem B, Petrov D, Jurašin DD, Bakarić D. Deciphering the origin of the melting profile of unilamellar phosphatidylcholine liposomes by measuring the turbidity of its suspensions. SOFT MATTER 2022; 18:6703-6715. [PMID: 36017811 DOI: 10.1039/d2sm00878e] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The elucidation of the thermal properties of phosphatidylcholine liposomes is often based on the analysis of the thermal capacity profiles of multilamellar liposomes (MLV), which may qualitatively disagree with those of unilamellar liposomes (LUV). Experiments and interpretation of LUV liposomes is further complicated by aggregation and lamellarization of lipid bilayers in a short time period, which makes it almost impossible to distinguish the signatures of the two types of bilayers. To characterize independently MLV and LUV of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), the latter were prepared with the addition of small amounts of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylglycerol (DPPG) which, due to the sterical hindrance and negative charge at a given pH value, cause LUV repellence and contribute to their stability. Differential scanning calorimetry curves and temperature-dependent UV/Vis spectra of the prepared MLV and LUV were measured. Multivariate analysis of spectrophotometric data determined the phase transition temperatures (pretransition at Tp and the main phase transition at Tm), and based on the changes in turbidities, the thickness of the lipid bilayer in LUV was determined. The obtained data suggested that the curvature change is a key distinguishing factor in MLV and LUV heat capacity profiles. By combining the experimental results and those obtained by MD simulations, the interfacial water layer was characterized and its contribution to the thermal properties of LUV was discussed.
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Affiliation(s)
- Petra Maleš
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
| | - Barbara Pem
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
| | - Dražen Petrov
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, 1180 Vienna, Austria
| | - Darija Domazet Jurašin
- Division for Physical Chemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Danijela Bakarić
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
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10
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Domínguez-Arca V, Sabín J, García-Río L, Bastos M, Taboada P, Barbosa S, Prieto G. On the structure and stability of novel cationic DPPC liposomes doped with gemini surfactants. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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11
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Kim S, Hyeon C. Location of the TEMPO moiety of TEMPO-PC in phosphatidylcholine bilayers is membrane phase-dependent. Biophys J 2022; 121:2550-2556. [PMID: 35651317 DOI: 10.1016/j.bpj.2022.05.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/23/2022] [Accepted: 05/26/2022] [Indexed: 11/25/2022] Open
Abstract
The (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) moiety tethered to the headgroup of phosphatidylcholine (PC) lipid is employed in spin labeling electron paramagnetic resonance (EPR) spectroscopy to probe the water dynamics near lipid bilayer interfaces. Due to its amphiphilic character, however, TEMPO spin label could partition between aqueous and lipid phases, and may even be stabilized in the lipid phase. Accurate assessment of the TEMPO-PC configuration in bilayer membranes is essential for correctly interpreting the data from measurements. Here, we carry out all-atom molecular dynamics (MD) simulations of TEMPO-PC probe in single-component lipid bilayers at varying temperatures, using two standard MD force fields. We find that for DPPC membrane whose gel-to-fluid lipid phase transition occurs at 314 K, while the TEMPO spin label is stabilized above the bilayer interface in the gel phase, there is a preferential location of TEMPO below the membrane interface in the fluid phase. For bilayers made of unsaturated lipids, DOPC and POPC, which adopt the fluid phase at ambient temperature, TEMPO is unequivocally stabilized inside the bilayers. Our finding of membrane phase-dependent positioning of TEMPO moiety highlights the importance of assessing the packing order and fluidity of lipids under a given measurement condition.
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Affiliation(s)
- Seonghoon Kim
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Korea
| | - Changbong Hyeon
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Korea.
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12
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Maleš P, Brkljača Z, Domazet Jurašin D, Bakarić D. New spirit of an old technique: Characterization of lipid phase transitions via UV/Vis spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 272:121013. [PMID: 35176647 DOI: 10.1016/j.saa.2022.121013] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/26/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
One of the advantages of investigating lipid phase transitions by thermoanalytical techniques such as DSC is manifested in the proportionality of the signal strength on a DSC curve, attributed to a particular thermotropic event, and its cooperativity degree. Accordingly, the pretransition of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) is less noticeable than its main phase transition; as a matter of fact, when DSC measurements are performed at low heating rate, such low-cooperativity phase transition could go (almost) unnoticed. The aim of this work is to present temperature-dependent UV/Vis spectroscopy, based on a temperature-dependent change in DPPC suspension turbidity, as a technique applicable for determination of lipid phase transition temperatures. Multivariate analyzes of the acquired UV/Vis spectra show that phase transitions of the low-cooperativity degree, such as pretransitions, can be identified with the same certainty as transitions of a high-cooperativity degree.
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Affiliation(s)
- Petra Maleš
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Zlatko Brkljača
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Darija Domazet Jurašin
- Division for Physical Chemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Danijela Bakarić
- Division for Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia.
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13
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Stelter D, Keyes T. Membrane Phase Transitions in Lipid-Wrapped Nanoparticles. J Phys Chem B 2022; 126:2507-2512. [DOI: 10.1021/acs.jpcb.1c10903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David Stelter
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Tom Keyes
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
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14
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Miles CM, Hsu PC, Dixon AM, Khalid S, Sosso GC. Lipid bilayers as potential ice nucleating agents. Phys Chem Chem Phys 2022; 24:6476-6491. [PMID: 35254357 DOI: 10.1039/d1cp05465a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cellular damage is a key issue in the context of cryopreservation. Much of this damage is believed to be caused by extracellular ice formation at temperatures well above the homogeneous freezing point of pure water. Hence the question: what initiates ice nucleation during cryopreservation? In this paper, we assess whether cellular membranes could be responsible for facilitating the ice nucleation process, and what characteristics would make them good or bad ice nucleating agents. By means of molecular dynamics simulations, we investigate a number of phospholipids and lipopolysaccharide bilayers at the interface with supercooled liquid water. While these systems certainly appear to act as ice nucleating agents, it is likely that other impurities might also play a role in initiating extracellular ice nucleation. Furthermore, we elucidate the factors which affect a bilayer's ability to act as an ice nucleating agent; these are complex, with specific reference to both chemical and structural factors. These findings represent a first attempt to pinpoint the origin of extracellular ice nucleation, with important implications for the cryopreservation process.
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Affiliation(s)
| | - Pin-Chia Hsu
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK
| | - Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
| | - Syma Khalid
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.,Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Gabriele C Sosso
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
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15
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Frigini EN, Porasso RD. Effect of Ionic Strength on Ibuprofenate Adsorption on a Lipid Bilayer of Dipalmitoylphosphatidylcholine from Molecular Dynamics Simulations. J Phys Chem B 2022; 126:1941-1950. [PMID: 35226503 DOI: 10.1021/acs.jpcb.1c09301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this work, the free energy change in the process of transferring ibuprofenate from the bulk solution to the center of a model of the dipalmitoylphosphatidylcholine bilayer at different NaCl concentrations was calculated. Two minima were found in the free energy profile: a local minimum, located in the vicinity of the membrane, and the global free energy minimum, found near the headgroup region. The downward shift of free energy minima with increasing NaCl concentration is consistent with the results of previous works. Conversely, the upward shift of the free energy maximum with increasing ionic strength is due to the competition of sodium ions and lipids molecules to coordinate with ibuprofenate and neutralize its charge. In addition, normal molecular dynamics simulations were performed to study the effects of the ibuprofenate on the lipid bilayer and in the presence of a high ibuprofenate concentration. The effect of ionic strength on the properties of the lipid bilayer and on lipid-drug interactions was analyzed. The area per lipid shrinking with increasing ionic strength, volume of lipids, and thickness of the bilayer is consistent with the experimental results. At a very high ibuprofenate concentration, the lipid bilayer dehydrates, and it consequently transforms into the gel phase, thus blocking the permeation.
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Affiliation(s)
- Ezequiel N Frigini
- Instituto de Matemáticas Aplicada San Luis, CONICET, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Avenida Ejército de los Andes 950, 5700 San Luis, Argentina
| | - Rodolfo D Porasso
- Instituto de Matemáticas Aplicada San Luis, CONICET, Facultad de Ciencias Físico Matemáticas y Naturales, Universidad Nacional de San Luis, Avenida Ejército de los Andes 950, 5700 San Luis, Argentina
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16
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Xu H, Tae H, Cho NJ, Huang C, Hsia KJ. Thermodynamic Modeling of Solvent-Assisted Lipid Bilayer Formation Process. MICROMACHINES 2022; 13:mi13010134. [PMID: 35056299 PMCID: PMC8777629 DOI: 10.3390/mi13010134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/22/2022]
Abstract
The solvent-assisted lipid bilayer (SALB) formation method provides a simple and efficient, microfluidic-based strategy to fabricate supported lipid bilayers (SLBs) with rich compositional diversity on a wide range of solid supports. While various studies have been performed to characterize SLBs formed using the SALB method, relatively limited work has been carried out to understand the underlying mechanisms of SALB formation under various experimental conditions. Through thermodynamic modeling, we studied the experimental parameters that affect the SALB formation process, including substrate surface properties, initial lipid concentration, and temperature. It was found that all the parameters are critically important to successfully form high-quality SLBs. The model also helps to identify the range of parameter space within which conformal, homogeneous SLBs can be fabricated, and provides mechanistic guidance to optimize experimental conditions for lipid membrane-related applications.
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Affiliation(s)
- Hongmei Xu
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore;
| | - Hyunhyuk Tae
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore;
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore;
- Correspondence: (N.-J.C.); (C.H.); (K.J.H.)
| | - Changjin Huang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore;
- Correspondence: (N.-J.C.); (C.H.); (K.J.H.)
| | - K. Jimmy Hsia
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore;
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
- Correspondence: (N.-J.C.); (C.H.); (K.J.H.)
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17
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Velez-Saboyá CS, Guzmán-Sepúlveda JR, Ruiz-Suárez JC. Phase transitions of liposomes: when light meets heat. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:124002. [PMID: 34936996 DOI: 10.1088/1361-648x/ac45b7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Phase transitions of liposomes are normally studied by differential scanning calorimetry. A suspension of liposomes is subjected to an increase (decrease) of temperature and when heat is absorbed (released), the liposomes transit from a gel (liquid) to a liquid (gel) phase. This endothermic (exothermic) process takes place at a temperature called the melting temperatureTm, which is distinctive of the type of lipids forming the vesicles. The vesicles, though, also modify their size in the transition. Indeed, the thickness of the membranes decreases (increases) because carbon tails misalign (align). Concomitant with the modifications in the membrane thickness, the diameter (D) of the liposomes changes too. Therefore, when they are inspected by light, the scattered signal carries information from such dilatation (contraction) process. We performed careful experiments using dynamic light scattering as a function of temperature to detect the size changes of different liposomes. Gaussian fits of the derivatives of theDvsTcurves coincide within 1% with thermograms, which hints to the possibility of performing thermodynamic studies of lipid systems employing light.
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Affiliation(s)
| | | | - J C Ruiz-Suárez
- CINVESTAV-Monterrey, PIIT, Apodaca, Nuevo León 66600, Mexico
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18
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Mast MP, Modh H, Champanhac C, Wang JW, Storm G, Krämer J, Mailänder V, Pastorin G, Wacker MG. Nanomedicine at the crossroads - A quick guide for IVIVC. Adv Drug Deliv Rev 2021; 179:113829. [PMID: 34174332 DOI: 10.1016/j.addr.2021.113829] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/17/2021] [Accepted: 06/10/2021] [Indexed: 02/08/2023]
Abstract
For many years, nanomedicine is pushing the boundaries of drug delivery. When applying these novel therapeutics, safety considerations are not only a key concern when entering clinical trials but also an important decision point in product development. Standing at the crossroads, nanomedicine may be able to escape the niche markets and achieve wider acceptance by the pharmaceutical industry. While there is a new generation of drug delivery systems, the extracellular vesicles, standing on the starting line, unresolved issues and new challenges emerge from their translation from bench to bedside. Some key features of injectable nanomedicines contribute to the predictability of the pharmacological and toxicological effects. So far, only a few of the physicochemical attributes of nanomedicines can be justified by a direct mathematical relationship between the in vitro and the in vivo responses. To further develop extracellular vesicles as drug carriers, we have to learn from more than 40 years of clinical experience in liposomal delivery and pass on this knowledge to the next generation. Our quick guide discusses relationships between physicochemical characteristics and the in vivo response, commonly referred to as in vitro-in vivo correlation. Further, we highlight the key role of computational methods, lay open current knowledge gaps, and question the established design strategies. Has the recent progress improved the predictability of targeted delivery or do we need another change in perspective?
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19
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Schönfeldová T, Piller P, Kovacik F, Pabst G, Okur HI, Roke S. Lipid Melting Transitions Involve Structural Redistribution of Interfacial Water. J Phys Chem B 2021; 125:12457-12465. [PMID: 34730965 PMCID: PMC8607985 DOI: 10.1021/acs.jpcb.1c06868] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/15/2021] [Indexed: 11/29/2022]
Abstract
Morphological and gel-to-liquid phase transitions of lipid membranes are generally considered to primarily depend on the structural motifs in the hydrophobic core of the bilayer. Structural changes in the aqueous headgroup phase are typically not considered, primarily because they are difficult to quantify. Here, we investigate structural changes of the hydration shells around large unilamellar vesicles (LUVs) in aqueous solution, using differential scanning calorimetry (DSC), and temperature-dependent ζ-potential and high-throughput angle-resolved second harmonic scattering measurements (AR-SHS). Varying the lipid composition from 1,2-dimyristoyl-sn-glycero-3-phosphocholine(DMPC) to 1,2-dimyristoyl-sn-glycero-3-phosphate (DMPA), to 1,2-dimyristoyl-sn-glycero-3-phospho-l-serine (DMPS), we observe surprisingly distinct behavior for the different systems that depend on the chemical composition of the hydrated headgroups. These differences involve changes in hydration following temperature-induced counterion redistribution, or changes in hydration following headgroup reorientation and Stern layer compression.
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Affiliation(s)
- Tereza Schönfeldová
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), Institute of Materials
Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Paulina Piller
- Institute
of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstrasse 50/III, Graz 8010, Austria
| | - Filip Kovacik
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), Institute of Materials
Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Georg Pabst
- Institute
of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Humboldtstrasse 50/III, Graz 8010, Austria
| | - Halil I. Okur
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), Institute of Materials
Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Department
of Chemistry and National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
| | - Sylvie Roke
- Laboratory
for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), Institute of Materials
Science (IMX), School of Engineering (STI), and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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20
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Lee OS, Madjet ME, Mahmoud KA. Antibacterial Mechanism of Multifunctional MXene Nanosheets: Domain Formation and Phase Transition in Lipid Bilayer. NANO LETTERS 2021; 21:8510-8517. [PMID: 34402623 DOI: 10.1021/acs.nanolett.1c01986] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
MXenes, two-dimensional metal carbides or nitrides with multifunctional surfaces, are one of the most promising antibacterial nanoscale materials. However, their putative bactericidal mechanism is elusive. To study their bactericidal mechanism, we investigated the interaction between a MXene nanosheet and a model bacterial membrane by molecular dynamics simulations and found that an adsorbed MXene on a membrane surface induced a local phase transition in a domain where the fluidity of the phospholipid in this domain at room temperature was comparable with that of the gel phase. The domain also showed a denser and thinner phospholipid membrane structure than the peripheral phospholipids. By comparing it with our previous experiments of the bactericidal activity of MXenes, we proposed the leakage of intercellular molecules at the phase boundary defects as a possible bactericidal mechanism of MXenes that leads to cell lysis. This study provides a useful model for tailoring new bactericidal nanomaterials.
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Affiliation(s)
- One-Sun Lee
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, PO Box 34110 Doha, Qatar
| | - Mohamed E Madjet
- Max-Planck-Institut für Physik, Komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - Khaled A Mahmoud
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, PO Box 34110 Doha, Qatar
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21
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Talló K, Pons R, González C, López O. Monitoring the formation of a colloidal lipid gel at the nanoscale: vesicle aggregation driven by a temperature-induced mechanism. J Mater Chem B 2021; 9:7472-7481. [PMID: 34551044 DOI: 10.1039/d1tb01020d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Colloidal gels made of lipid vesicles at highly diluted conditions have been recently described. The structure and composition of this type of material could be especially relevant for studies that combine model lipid membranes with proteins, peptides, or enzymes to replicate biological conditions. Details about the nanoscale events that occur during the formation of such gels would motivate their future application. Thus, in this work we investigate the gelation mechanism, which consists of a lipid dispersion of vesicles going through a process that involves freezing and heating. The appropriate combination of techniques (transmission electron microscopy, differential scanning calorimetry and synchrotron small angle X-ray scattering) allowed in-depth analysis of the different events that give rise to the formation of the gel. Results showed how freezing damaged the lipid dispersion, causing a polydisperse suspension of membrane fragments and vesicles upon melting. Heating above the lipids' main phase transition temperature promoted the formation of elongated tubular structures. After cooling, these lipid tubes broke down into vesicles that formed branched aggregates across the aqueous phase, obtaining a material with gel characteristics. These mechanistic insights may also allow finding new ways to interact with lipid vesicles to form structured materials. Future works might complement the presented results with molecular dynamics or nuclear magnetic resonance experiments.
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Affiliation(s)
- Kirian Talló
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
| | - Ramon Pons
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
| | - César González
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
| | - Olga López
- Department of Surfactants and Nanobiotechnology, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC), C/Jordi Girona 18-26, 08034 Barcelona, Spain.
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22
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Bouquiaux C, Castet F, Champagne B. Unravelling the Effects of Cholesterol on the Second-Order Nonlinear Optical Responses of Di-8-ANEPPS Dye Embedded in Phosphatidylcholine Lipid Bilayers. J Phys Chem B 2021; 125:10195-10212. [PMID: 34491062 DOI: 10.1021/acs.jpcb.1c05630] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cholesterol is known for its role in maintaining the correct fluidity and rigidity of the animals cell membranes and thus their functions. Assessing the content and the role of cholesterol in lipid bilayers is therefore of crucial importance for a deeper understanding and control of membrane functioning. In this computational work, we investigate bilayers built from three types of glycerophospholipid phosphatidylcholine (PC) lipids, namely dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and dioleoylphosphatidylcholine (DOPC), and containing different amounts of cholesterol by analyzing the second-harmonic generation (SHG) nonlinear optical (NLO) response of a probe molecule, di-8-ANEPPS, inserted into the membranes. This molecular property presents the advantage to be specific to interfacial regions such as lipid bilayers. To unravel these effects, Molecular Dynamics (MD) simulations have been performed on both DPPC and DOPC lipids by varying the cholesterol mole fraction (from 0 to 0.66), while POPC was only considered as a pure bilayer. In the case of the structural properties of the bilayers, all the analyses converge toward the same conclusion: as the mole fraction of cholesterol increases, the systems become more rigid, confirming the condensing effect of cholesterol. In addition, the chromophore is progressively more aligned with respect to the normal to the bilayer. On the contrary, addition of unsaturation disorders the lipid bilayers, with barely no impact on the alignment of the chromophore. Then, using the frames obtained from the MD simulations, the first hyperpolarizability β of the dye in its environment has been computed at the TDDFT level. On the one hand, the addition of cholesterol induces a progressive increase of the diagonal component the β tensor parallel to the bilayer normal. On the other hand, larger β values have been calculated for the unsaturated than for the saturated lipid systems. In summary, this study illustrates the relationship between the composition and structure of the bilayers and the NLO responses of the embedded dye.
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Affiliation(s)
- Charlotte Bouquiaux
- Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium
| | - Frédéric Castet
- , Institut des Sciences Moléculaires, UMR 5255 CNRS, University of Bordeaux, cours de la Libération 351, F-33405 Talence Cedex, France
| | - Benoît Champagne
- Theoretical Chemistry Lab, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, rue de Bruxelles, 61, B-5000 Namur, Belgium
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23
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Rogers JR, Espinoza Garcia G, Geissler PL. Membrane hydrophobicity determines the activation free energy of passive lipid transport. Biophys J 2021; 120:3718-3731. [PMID: 34302793 PMCID: PMC8456290 DOI: 10.1016/j.bpj.2021.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 07/07/2021] [Accepted: 07/19/2021] [Indexed: 12/16/2022] Open
Abstract
The collective behavior of lipids with diverse chemical and physical features determines a membrane's thermodynamic properties. Yet, the influence of lipid physicochemical properties on lipid dynamics, in particular interbilayer transport, remains underexplored. Here, we systematically investigate how the activation free energy of passive lipid transport depends on lipid chemistry and membrane phase. Through all-atom molecular dynamics simulations of 11 chemically distinct glycerophospholipids, we determine how lipid acyl chain length, unsaturation, and headgroup influence the free energy barriers for two elementary steps of lipid transport: lipid desorption, which is rate limiting, and lipid insertion into a membrane. Consistent with previous experimental measurements, we find that lipids with longer, saturated acyl chains have increased activation free energies compared to lipids with shorter, unsaturated chains. Lipids with different headgroups exhibit a range of activation free energies; however, no clear trend based solely on chemical structure can be identified, mirroring difficulties in the interpretation of previous experimental results. Compared to liquid-crystalline phase membranes, gel phase membranes exhibit substantially increased free energy barriers. Overall, we find that the activation free energy depends on a lipid's local hydrophobic environment in a membrane and that the free energy barrier for lipid insertion depends on a membrane's interfacial hydrophobicity. Both of these properties can be altered through changes in lipid acyl chain length, lipid headgroup, and membrane phase. Thus, the rate of lipid transport can be tuned through subtle changes in local membrane composition and order, suggesting an unappreciated role for nanoscale membrane domains in regulating cellular lipid dynamics.
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Affiliation(s)
- Julia R Rogers
- Department of Chemistry, University of California Berkeley, Berkeley, California.
| | | | - Phillip L Geissler
- Department of Chemistry, University of California Berkeley, Berkeley, California; Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California.
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24
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Dutta P, Pramanik D, Singh JK. Phase Behavior of Pure PSPC and PEGylated Multicomponent Lipid and Their Interaction with Paclitaxel: An All-Atom MD Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:10259-10271. [PMID: 34406778 DOI: 10.1021/acs.langmuir.1c01049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Exploring structural behavior of pure 1-palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine (PSPC) and multicomponent PSPC and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N[amino(poly(ethylene glycol))-2000] (DSPE-PEG2000) membranes and their interaction with pharmaceutically important drugs carry huge importance in drug delivery. Using all-atom molecular dynamics (MD) simulations, we investigated the phase behavior of pure and PEGylated membranes at the temperature range of 280-360 K. We observe a gel-to-liquid crystalline phase transition for pure PSPC between 320 and 330 K, and in the case of multicomponent membranes, at 320 K, a coexistence of order-disorder phases is observed, which gradually transform to a complete liquid crystalline to gel phase between 320 and 310 K. We further studied the interaction of Paclitaxel with pure PSPC and PEGylated bilayers and elucidated the interaction behavior of Paclitaxel at the bilayer interfaces. Understanding of structural and interaction behaviors of the PEGylated bilayers with Paclitaxel will help to explore Paclitaxel-based drug applications in the future.
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Affiliation(s)
- Prantar Dutta
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Debabrata Pramanik
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Jayant K Singh
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
- Prescience Insilico Private Limited, Old Madras Road, Bangalore 560049, India
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25
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Yoshida K, Horii K, Saito A, Takashima A, Nishio I. Aggregation of Water Molecules to Phospholipid Head Groups Accompanied with Separation into Water‐ and Polysaccharide‐Rich Phases in Water‐in‐Oil Emulsions. ChemistrySelect 2021. [DOI: 10.1002/slct.202101146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kazunari Yoshida
- Graduate School of Science and Engineering Yamagata University 4-3-16, Jonan Yonezawa-shi Yamagata 992-8510 Japan
| | - Keitaro Horii
- College of Science and Engineering Aoyama Gakuin University 5-10-1 Fuchinobe, Chuo-ku Sagamihara-shi Kanagawa 252-5258 Japan
| | - Azusa Saito
- College of Science and Engineering Aoyama Gakuin University 5-10-1 Fuchinobe, Chuo-ku Sagamihara-shi Kanagawa 252-5258 Japan
| | - Akito Takashima
- College of Science and Engineering Aoyama Gakuin University 5-10-1 Fuchinobe, Chuo-ku Sagamihara-shi Kanagawa 252-5258 Japan
| | - Izumi Nishio
- College of Science and Engineering Aoyama Gakuin University 5-10-1 Fuchinobe, Chuo-ku Sagamihara-shi Kanagawa 252-5258 Japan
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26
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Kozuch DJ, Stillinger FH, Debenedetti PG. Effects of Trehalose on Lipid Membranes under Rapid Cooling using All-Atom and Coarse-Grained Molecular Simulations. J Phys Chem B 2021; 125:5346-5357. [PMID: 33978410 DOI: 10.1021/acs.jpcb.1c02575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigate the effect of the cryopreservative α-α-trehalose on a model 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid membrane undergoing cooling from 350 to 250 K using all-atom (AA) and coarse-grained (CG) molecular dynamics simulation. In the AA simulations, we find that the addition of trehalose alters the Lα (liquid crystalline) to Pβ (ripple) phase transition, suppressing the major domain of the Pβ phase and increasing the degree of leaflet interdigitation (the minor domain) which yields a thinner membrane with a higher area per lipid. Calculation of dihedral angle distributions for the lipid tails shows a greater fraction of gauche angles in the Pβ phase as trehalose concentration is increased, indicating that trehalose increases lipid disorder in the membrane. In contrast, the CG simulations transition directly from the Lα to the Lβ (gel) phase upon cooling without exhibiting the Pβ phase (likely due to increased lipid mobility in the CG system). Even so, the CG simulations show that the addition of trehalose clearly suppresses the Lα to Lβ phase transition, demonstrating that trehalose increases lipid disorder at low temperatures for the CG system, similar to the AA. Analysis using a two-state binding model provides net affinity coefficients between trehalose and the membrane as well as trehalose partition coefficients between the membrane interface and the bulk solution for both the AA and CG systems.
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Affiliation(s)
- Daniel J Kozuch
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Frank H Stillinger
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Pablo G Debenedetti
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
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27
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Lee J, Yoon S, Chang R. Chlorosulfolipid (Danicalipin A) Membrane Structure: Hybrid Molecular Dynamics Simulation Studies. J Phys Chem Lett 2021; 12:4537-4542. [PMID: 33961748 DOI: 10.1021/acs.jpclett.1c01026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Chlorosulfolipids (CSLs) are major components of flagellar membranes in sea algae. Unlike typical biological lipids, CSLs contain hydrophilic sulfate and chloride groups in the hydrocarbon tail; this has deterred the prediction of the CSL membrane structure since 1960. In this study, we combine coarse-grained (CG) and atomistic molecular dynamics (MD) simulations to gain significant insights into the membrane structure of Danicalipin A, which is one of the typical CSLs. It is observed from the CG MD that Danicalipin A lipids form a stable monolayer membrane structure wherein the hydrocarbon moieties are sandwiched by hydrophilic sulfate and chloride groups in both the head and tail regions. On the basis of the mesoscopic structure, we built the corresponding atomistic model to investigate the integrity of the CSL monolayer membrane structure. The monolayer membrane comprising bent lipids shows high thermal stability up to 313 K. The gel-liquid crystalline phase transition is observed around 300 K.
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Affiliation(s)
- Junyeol Lee
- Department of Chemistry, Kwangwoon University, Seoul 01897, Republic of Korea
| | - Seungmin Yoon
- Department of Chemistry, Kwangwoon University, Seoul 01897, Republic of Korea
| | - Rakwoo Chang
- Department of Applied Chemistry, University of Seoul, Seoul, 02504, Republic of Korea
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28
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Han J, Iimure Y, Okamoto Y, Suga K, Umakoshi H. Structure and Properties Characterization of Amphiphilic Dendrons Modified Lipid Membrane. CHEM LETT 2021. [DOI: 10.1246/cl.200633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Jin Han
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Yosuke Iimure
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Yukihiro Okamoto
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Keishi Suga
- Department of Chemical Engineering, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
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29
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Liposomes embedded in layer by layer constructs as simplistic extracellular vesicles transfer model. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 121:111813. [PMID: 33579457 DOI: 10.1016/j.msec.2020.111813] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/03/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023]
Abstract
Extracellular vesicles (EVs) are particles originating from the exfoliation of the cellular membrane. They are involved in cell-to-cell and cell-to-matrix signaling, exchange of bioactive molecules, tumorigenesis and metastasis, among others. To mitigate the limited understanding of EVs transfer phenomena, we developed a simplistic model that mimics EVs and their interactions with cells and the extracellular matrix. The proposed model is a layer by layer (LbL) film built from the polycationic poly-l-lysine (PLL) and the glycosaminoglycan hyaluronic acid (HA) to provide ECM mimicry. Positively charged 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and N1,N1,N14,N14-tetramethyl-N1,N14-ditetradecyltetradecane-1,14-diaminium dibromide (GS14) liposomes were embedded in this construct to act as EVs analogs. To simulate EVs carrying substances, Nile Red was loaded as a model of lipophilic cargo molecules. The integration of each component was followed by quartz crystal microbalance measurements, which confirmed the immobilization of intact liposomes on the underlying (PLL/HA)3 soft film. The release of Nile Red from liposomes either embedded in the LbL construct or exposed at its surface revealed a fast first order release. This system was validated as a model for EV/cell interactions by incubation with breast cancer cells MDA-MB-231. We observed higher internalization for embedded liposomes when compared with surface-exposed ones, showcasing that the ECM mimic layers do not constitute a barrier to liposome/cell interactions but favor them.
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30
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Duncan KM, Casey A, Gobrogge CA, Trousdale RC, Piontek SM, Cook MJ, Steel WH, Walker RA. Coumarin Partitioning in Model Biological Membranes: Limitations of log P as a Predictor. J Phys Chem B 2020; 124:8299-8308. [DOI: 10.1021/acs.jpcb.0c06109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Katelyn M. Duncan
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Aoife Casey
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Christine A. Gobrogge
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Rhys C. Trousdale
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Stefan M. Piontek
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Matthew J. Cook
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - William H. Steel
- Department of Chemistry, York College of Pennsylvania, York, Pennsylvania 17403, United States
| | - Robert A. Walker
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
- Montana Materials Science Program, Montana State University, Bozeman, Montana 59717, United States
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31
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Horne JE, Brockwell DJ, Radford SE. Role of the lipid bilayer in outer membrane protein folding in Gram-negative bacteria. J Biol Chem 2020; 295:10340-10367. [PMID: 32499369 PMCID: PMC7383365 DOI: 10.1074/jbc.rev120.011473] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/03/2020] [Indexed: 01/09/2023] Open
Abstract
β-Barrel outer membrane proteins (OMPs) represent the major proteinaceous component of the outer membrane (OM) of Gram-negative bacteria. These proteins perform key roles in cell structure and morphology, nutrient acquisition, colonization and invasion, and protection against external toxic threats such as antibiotics. To become functional, OMPs must fold and insert into a crowded and asymmetric OM that lacks much freely accessible lipid. This feat is accomplished in the absence of an external energy source and is thought to be driven by the high thermodynamic stability of folded OMPs in the OM. With such a stable fold, the challenge that bacteria face in assembling OMPs into the OM is how to overcome the initial energy barrier of membrane insertion. In this review, we highlight the roles of the lipid environment and the OM in modulating the OMP-folding landscape and discuss the factors that guide folding in vitro and in vivo We particularly focus on the composition, architecture, and physical properties of the OM and how an understanding of the folding properties of OMPs in vitro can help explain the challenges they encounter during folding in vivo Current models of OMP biogenesis in the cellular environment are still in flux, but the stakes for improving the accuracy of these models are high. OMP folding is an essential process in all Gram-negative bacteria, and considering the looming crisis of widespread microbial drug resistance it is an attractive target. To bring down this vital OMP-supported barrier to antibiotics, we must first understand how bacterial cells build it.
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Affiliation(s)
- Jim E Horne
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - David J Brockwell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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32
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Pires F, Magalhães-Mota G, Geraldo VPN, Ribeiro PA, Oliveira ON, Raposo M. The impact of blue light in monolayers representing tumorigenic and nontumorigenic cell membranes containing epigallocatechin-3-gallate. Colloids Surf B Biointerfaces 2020; 193:111129. [PMID: 32502833 DOI: 10.1016/j.colsurfb.2020.111129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 04/21/2020] [Accepted: 05/11/2020] [Indexed: 02/08/2023]
Abstract
Natural products such as epigallocatechin-3-gallate (EGCG) have been suggested for complementary treatments of cancer, since they lower toxic side effects of anticancer drugs, and possess anti-inflammatory and antioxidant properties that inhibit carcinogenesis. Their effects on cancer cells depend on interactions with the membrane, which is the motivation to investigate Langmuir monolayers as simplified membrane models. In this study, EGCG was incorporated in zwitterionic dipalmitoyl phosphatidyl choline (DPPC) and anionic dipalmitoyl phosphatidyl serine (DPPS) Langmuir monolayers to simulate healthy and cancer cells membranes, respectively. EGCG induces condensation in surface pressure isotherms for both DPPC and DPPS monolayers, interacting mainly via electrostatic forces and hydrogen bonding with the choline and phosphate groups of the phospholipids, according to data from polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). Both monolayers become more compressible upon interaction with EGCG, which may be correlated to the synergy between EGCG and anticancer drugs reported in the literature. The interaction with EGCG is stronger for DPPC, leading to stronger morphological changes in Brewster angle microscopy (BAM) images and higher degree of condensation in the surface pressure isotherms. The changes induced by blue irradiation on DPPC and DPPS monolayers were largely precluded when EGCG was incorporated, thus confirming its antioxidant capacity for both types of membrane.
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Affiliation(s)
- Filipa Pires
- CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Gonçalo Magalhães-Mota
- CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | | | - Paulo A Ribeiro
- CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | | | - Maria Raposo
- CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
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33
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Kumar Basak U, Roobala C, Basu JK, Maiti PK. Size-dependent interaction of hydrophilic/hydrophobic ligand functionalized cationic and anionic nanoparticles with lipid bilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:104003. [PMID: 31722322 DOI: 10.1088/1361-648x/ab5770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We study the nature of nanoparticle (NPs)-membrane interaction as a function of nanoparticle size for different functionalization using molecular dynamics simulation. Zinc sulphide quantum dots of size, 2 nm and 4 nm are used as model NPs, and DLPC and DPPC lipid bilayers are used as model membranes. We use coarse-grained polarizable MARTINI model (MPW) to simulate the NPs and lipid bilayers. Our simulation results show that uncharged bare NPs penetrate the lipid bilayers and embed themselves within the hydrophobic core of the bilayer both in the gel and fluid phases. NPs of size 4 nm are shown to disrupt the bilayer. The bilayer recovers from the damages caused by smaller NPs of size 2 nm. In case of either purely hydrophilic or hybrid (with hydrophilic/hydrophobic ratio of 2:1) ligand-functionalized NPs of smaller size (shell size 2 nm), only cationic NPs bind to the bilayer. However, for larger NPs with a shell size of 4 nm, both anionic and cationic hybrid functionalized NPs bind to the bilayer. The performance of standard Martini (SM) force field for the charged NP/bilayer systems has also been tested and compared with the results obtained using MPW model. Although the overall trend that the cationic NPs interact strongly with the bilayers than their anionic counterparts has been captured correctly using SM, the adsorption behaviour of the functionalized NPs differ significantly in the SM force field. The interaction of anionic NPs with both fluid and gel bilayers has been observed to be least accurately represented in the SM force field.
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34
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Gu RX, Baoukina S, Tieleman DP. Phase Separation in Atomistic Simulations of Model Membranes. J Am Chem Soc 2020; 142:2844-2856. [DOI: 10.1021/jacs.9b11057] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Ruo-Xu Gu
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
| | - Svetlana Baoukina
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
| | - D. Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta T2N 1N4, Canada
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35
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Lin YC, Chipot C, Scheuring S. Annexin-V stabilizes membrane defects by inducing lipid phase transition. Nat Commun 2020; 11:230. [PMID: 31932647 PMCID: PMC6957514 DOI: 10.1038/s41467-019-14045-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 12/11/2019] [Indexed: 02/04/2023] Open
Abstract
Annexins are abundant cytoplasmic proteins, which bind to membranes that expose negatively charged phospholipids in a Ca2+-dependent manner. During cell injuries, the entry of extracellular Ca2+ activates the annexin membrane-binding ability, subsequently initiating membrane repair processes. However, the mechanistic action of annexins in membrane repair remains largely unknown. Here, we use high-speed atomic force microscopy (HS-AFM), fluorescence recovery after photobleaching (FRAP), confocal laser scanning microscopy (CLSM) and molecular dynamics simulations (MDSs) to analyze how annexin-V (A5) binds to phosphatidylserine (PS)-rich membranes leading to high Ca2+-concentrations at membrane, and then to changes in the dynamics and organization of lipids, eventually to a membrane phase transition. A5 self-assembly into lattices further stabilizes and likely structures the membrane into a gel phase. Our findings are compatible with the patch resealing through vesicle fusion mechanism in membrane repair and indicate that A5 retains negatively charged lipids in the inner leaflet in an injured cell. Annexins are cytoplasmic proteins, which bind to membranes exposing negatively charged phospholipids in a Ca2+-dependent manner. Here the authors use high-speed atomic force microscopy and other techniques to show that annexin-V self-assembles into highly structured lattices that lead to a membrane phase transition on PS-rich membranes.
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Affiliation(s)
- Yi-Chih Lin
- Department of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.,Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA
| | - Christophe Chipot
- UMR 7019, Université de Lorraine, Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, Vandoeuvre-lès-Nancy, F-54500, France.,Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL, 61801, USA
| | - Simon Scheuring
- Department of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA. .,Department of Physiology and Biophysics, Weill Cornell Medicine, 1300 York Avenue, New York, NY, 10065, USA.
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36
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Tong X, Moradipour M, Novak B, Kamali P, Asare SO, Knutson BL, Rankin SE, Lynn BC, Moldovan D. Experimental and Molecular Dynamics Simulation Study of the Effects of Lignin Dimers on the Gel-to-Fluid Phase Transition in DPPC Bilayers. J Phys Chem B 2019; 123:8247-8260. [DOI: 10.1021/acs.jpcb.9b05525] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Xinjie Tong
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Mahsa Moradipour
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Brian Novak
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Poorya Kamali
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Shardrack O. Asare
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Barbara L. Knutson
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Stephen E. Rankin
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Bert C. Lynn
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Dorel Moldovan
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
- Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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37
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Prislan I, Lokar M, Zirdum M, Valant J, Poklar Ulrih N. Contribution of headgroup and chain length of glycerophospholipids to thermal stability and permeability of liposomes loaded with calcein. Chem Phys Lipids 2019; 225:104807. [PMID: 31390525 DOI: 10.1016/j.chemphyslip.2019.104807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 10/26/2022]
Abstract
Biological membranes are complex systems that are composed of lipids, proteins and carbohydrates. They are difficult to study, so it is established practice to use lipid vesicles that consist of closed 'shells' of phospholipid bilayers as model systems to study various functional and structural aspects of lipid organisation. To define the effects of the structural properties of lipid vesicles on their phase behaviour, we investigated their headgroup and chain length, and the chemical bonds by which their acyl chains are attached to the glycerol moiety of glycerophospholipid species, in terms of phase transition temperature, enthalpy change and calcein permeability. We used differential scanning calorimetry to measure the temperature and enthalpy changes of phase transition, and fluorescence to follow calcein release through the bilayer structure. Our data show that longer acyl chains increase the stability of the lipid bilayers, whereas higher salt concentrations decrease the thermal stability and widen the phase transitions of these lipid bilayers. We discuss the possible reasons for the observed phase transition behaviour.
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Affiliation(s)
- Iztok Prislan
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000, Ljubljana, Slovenia
| | - Maruša Lokar
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000, Ljubljana, Slovenia
| | - Martina Zirdum
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000, Ljubljana, Slovenia
| | - Janez Valant
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000, Ljubljana, Slovenia
| | - Nataša Poklar Ulrih
- Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000, Ljubljana, Slovenia.
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38
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Zaki AM, Carbone P. Amphiphilic copolymers change the nature of the ordered-to-disordered phase transition of lipid membranes from discontinuous to continuous. Phys Chem Chem Phys 2019; 21:13746-13757. [PMID: 31209450 DOI: 10.1039/c9cp01293a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The phase behaviour as a function of temperature is explored for pure phospholipid (DPPC) and hybrid lipid-polymer (DPPC/Pluronic L64) bilayers with the aid of atomistic MD simulations. The range of the fixed-temperature simulations includes temperatures below and above the known melting temperature (Tm) for DPPC membranes. For the pure lipid bilayer, the main phase transition is discontinuous, as verified by the abrupt changes observed in the membrane structure, elasticity and the lipid diffusivity near the critical temperature Tm, which lies in the region 298.15-303.15 K. A pre-transition step is detected at 298.15 K which has been identified as the ripple phase (Pβ'), where ordered and disordered lipids coexist, causing thickness fluctuations. In the ordered gel phase, the positional ordering as assessed by the lipid radial distribution functions is long-range and some degree of hexagonal packing is measured. The hybrid bilayers on the other hand, transform from a more ordered to a disordered phase in a continuous manner, without finite jumps in their properties. No signs of the ripple phase are identified and the ordered phase exhibits very limited hexagonal packing and some positional ordering that decays fast. The effect of the inserted polymers in the two phases is reversed; at low temperatures, they render the membrane thinner, less cohesive and less ordered compared to the pure one, with the lipids assuming faster diffusion rates, whereas at high temperatures, the polymer interaction with the lipids acts reducing their diffusivity, but also increasing the lipid tail ordering and the membrane stiffness. The ability of the amphiphilic L64 copolymers to change the nature of the main phase transition of lipid membranes and their properties both in the ordered and the disordered phase is of vital importance for the prediction of both the efficacy of hybrid lipid/polymer nanoparticles as drug delivery vehicles as well as their potential adverse implications during interactions with healthy cell membranes.
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Affiliation(s)
- Afroditi Maria Zaki
- School of Chemical Engineering and Analytical Science, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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39
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Kirsch SA, Böckmann RA. Coupling of Membrane Nanodomain Formation and Enhanced Electroporation near Phase Transition. Biophys J 2019; 116:2131-2148. [PMID: 31103234 PMCID: PMC6554532 DOI: 10.1016/j.bpj.2019.04.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/17/2019] [Accepted: 04/18/2019] [Indexed: 12/29/2022] Open
Abstract
Biological cells are enveloped by a heterogeneous lipid bilayer that prevents the uncontrolled exchange of substances between the cell interior and its environment. In particular, membranes act as a continuous barrier for salt and macromolecules to ensure proper physiological functions within the cell. However, it has been shown that membrane permeability strongly depends on temperature and, for phospholipid bilayers, displays a maximum at the transition between the gel and fluid phase. Here, extensive molecular dynamics simulations of dipalmitoylphosphatidylcholine bilayers were employed to characterize the membrane structure and dynamics close to phase transition, as well as its stability with respect to an external electric field. Atomistic simulations revealed the dynamic appearance and disappearance of spatially related nanometer-sized thick ordered and thin interdigitating domains in a fluid-like bilayer close to the phase transition temperature (Tm). These structures likely represent metastable precursors of the ripple phase that vanished at increased temperatures. Similarly, a two-phase bilayer with coexisting gel and fluid domains featured a thickness minimum at the interface because of splaying and interdigitating lipids. For all systems, application of an external electric field revealed a reduced bilayer stability with respect to pore formation for temperatures close to Tm. Pore formation occurred exclusively in thin interdigitating membrane nanodomains. These findings provide a link between the increased membrane permeability and the structural heterogeneity close to phase transition.
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Affiliation(s)
- Sonja A Kirsch
- Computational Biology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Rainer A Böckmann
- Computational Biology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany.
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40
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Biological
membranes are tricky to investigate. They are complex
in terms of molecular composition and structure, functional
over a wide range of time scales, and characterized
by nonequilibrium conditions. Because of all of these
features, simulations are a great technique to study biomembrane
behavior. A significant part of the functional processes
in biological membranes takes place at the molecular
level; thus computer simulations are the method of
choice to explore how their properties emerge from specific
molecular features and how the interplay among the numerous
molecules gives rise to function over spatial and
time scales larger than the molecular ones. In this
review, we focus on this broad theme. We discuss the current
state-of-the-art of biomembrane simulations that, until
now, have largely focused on a rather narrow picture
of the complexity of the membranes. Given this, we
also discuss the challenges that we should unravel in the
foreseeable future. Numerous features such as the actin-cytoskeleton
network, the glycocalyx network, and nonequilibrium
transport under ATP-driven conditions have so far
received very little attention; however, the potential
of simulations to solve them would be exceptionally high. A
major milestone for this research would be that one day
we could say that computer simulations genuinely research
biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Matti Javanainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences , Flemingovo naḿesti 542/2 , 16610 Prague , Czech Republic.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Waldemar Kulig
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Tomasz Róg
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland.,MEMPHYS-Center for Biomembrane Physics
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41
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Zhao L, Tu Y, Fang H, Hamley IW, Wang Z. Self-Assembled Micellar Structures of Lipopeptides with Variable Number of Attached Lipid Chains Revealed by Atomistic Molecular Dynamics Simulations. J Phys Chem B 2018; 122:9605-9615. [PMID: 30253107 DOI: 10.1021/acs.jpcb.8b07877] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We present atomistic molecular dynamics simulation study of the self-assembly behavior of toll-like agonist lipopeptides (Pam nCSK4) in aqueous solutions. The variable number of hexadecyl lipid chains ( n = 1, 2, 3) per molecule has been experimentally suggested to have remarkable influence on their self-assembled nanostructures. Starting from preassembled spherical or bilayer configurations, the aggregates of lipopeptides, PamCSK4 and Pam2CSK4, which contain peptide sequences CSK4 linked to either mono- or dilipid chains (Pam), evolve into spherical-like micelles within 30 ns, whereas the self-assembled structure of trilipidated lipopeptides, Pam3CSK4, relaxes much slower and reaches an equilibrium state of flattened wormlike micelle with a bilayer packing structure. The geometric shapes and sizes, namely the gyration radii of spherical micelles and thickness of the flattened wormlike micelle, are found to be in good agreement with experimental measurements, which effectively validates the simulation models and employed force fields. Detailed analyses of molecular packing reveal that these self-assembled nanostructures all consist of a hydrophobic core constructed of lipid chains, a transitional layer, and a hydrophilic interfacial layer composed of peptide sequences. The average area per peptide head at the interfaces is found to be nearly constant for all micellar structures studied. The packing parameter of the lipopeptide molecules thus increases with the increase of the number of linked lipid chains, giving rise to the distinct micellar shape transition from spherical-like to flattened wormlike geometry with bilayer stacking, which is qualitatively different from the shape transitions of surfactant micelles induced by variation of concentration or salt type. To facilitate the close-packing of the lipid chains in the hydrophobic core, the lipopeptide molecules typically take the bent conformation with average tilt angles between the peptide sequences and the lipid chains ranging from 110° to 140°. This consequently affects the orientation angles of the lipid chains with respect to the radial or normal direction of the spherical-like or flattened wormlike micelles. In addition, the secondary structures of the peptides may also be altered by the number of lipid chains to which they are linked and the resultant micellar structures. Our simulation results on the microscopic structural features of the lipopeptide nanostructures may provide potential insights into their bioactivities and contribute to the design of bioactive medicines or drug carriers. The force fields built for these lipopeptides and the geometric packing discussions could also be adopted for simulating and understanding the self-assembly behavior of other bioactive amiphiphiles with similar chemical compositions.
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Affiliation(s)
- Liang Zhao
- College of Physical Science and Technology , Yangzhou University , Yangzhou , Jiangsu 225009 , China
| | - Yusong Tu
- College of Physical Science and Technology , Yangzhou University , Yangzhou , Jiangsu 225009 , China
| | - Haiping Fang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology , Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
| | - Ian W Hamley
- Department of Chemistry , University of Reading , Whiteknights, Reading RG6 6AD , United Kingdom
| | - Zuowei Wang
- School of Mathematical, Physical and Computational Sciences , University of Reading , Whiteknights, Reading RG6 6AX , United Kingdom
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42
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Biophysical methods: Complementary tools to study the influence of human steroid hormones on the liposome membrane properties. Biochimie 2018; 153:13-25. [DOI: 10.1016/j.biochi.2018.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/07/2018] [Indexed: 11/21/2022]
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43
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Li A, Schertzer JW, Yong X. Molecular dynamics modeling of Pseudomonas aeruginosa outer membranes. Phys Chem Chem Phys 2018; 20:23635-23648. [PMID: 30191217 DOI: 10.1039/c8cp04278k] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pseudomonas aeruginosa is a common Gram-negative bacterium and opportunistic human pathogen. The distinctive structure of its outer membrane (OM) and outer membrane vesicles (OMVs) plays a fundamental role in bacterial virulence, colonization ability, and antibiotic resistance. To provide critical insights into OM and OMV functionality, we conducted an all-atom molecular dynamics study of asymmetric membranes that are biologically relevant to P. aeruginosa. We hybridized a GLYCAM06-based lipopolysaccharides force field with the Stockholm lipids force field (Slipids) to model bilayer membranes with Lipid A molecules in one leaflet and physiologically relevant phospholipid molecules in the other, including 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG), and 1,2-dioleoyl-sn-glycero-3-phosphoglycerol (DOPG). In particular, a membrane with phospholipid composition representing the P. aeruginosa OM was constructed and modeled by mixing the physiologically dominant components. The detailed structure of membranes was characterized by area per lipid, transmembrane mass and charge densities, radial distribution function (RDF), deuterium order parameter (SCD) of acyl chains, and inclination angles of phosphates and disaccharide in Lipid A. The membrane fluidity in equilibrium and the hydration of functional groups were probed and characterized quantitatively. The consistent properties of the Lipid A leaflets in different membranes demonstrate its compatibility with various phospholipids present in the P. aeruginosa OM. The more ordered acyl chains of Lipid A compared to the cytoplasmic cell membrane contribute to the low permeability of bacterial outer membrane. The findings of this computational investigation of P. aeruginosa OM will further the understanding of microbial pathogenesis and enable future study of OMV biogenesis.
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Affiliation(s)
- Ao Li
- Department of Mechanical Engineering, Binghamton University, The State University of New York, Binghamton, New York 13902, USA.
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Khakbaz P, Klauda JB. Investigation of phase transitions of saturated phosphocholine lipid bilayers via molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1489-1501. [DOI: 10.1016/j.bbamem.2018.04.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 12/01/2022]
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Importance of Hydrophilic Groups on Modulating the Structural, Mechanical, and Interfacial Properties of Bilayers: A Comparative Molecular Dynamics Study of Phosphatidylcholine and Ion Pair Amphiphile Membranes. Int J Mol Sci 2018; 19:ijms19061552. [PMID: 29882873 PMCID: PMC6032153 DOI: 10.3390/ijms19061552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/16/2018] [Accepted: 05/18/2018] [Indexed: 12/25/2022] Open
Abstract
An ion pair amphiphile (IPA), a molecular complex composed of two oppositely charged amphiphiles, is a phospholipid mimic which differs from a phospholipid only in the hydrophilic compositions. Here, we utilized molecular dynamics (MD) simulations to compare the bilayer systems composed of phosphatidylcholines (PC) and alkyltrimethylammonium-alkylsulfate IPAs with various alkyl chain lengths. The membrane properties for both liquid-disordered (Ld) and gel (S) phase bilayers were examined via running simulations above and below the main transition temperatures. The electrostatic attraction between the IPA hydrophilic groups leads to a more ordered molecular packing within both S and Ld phase IPA membranes, as revealed by the molecular area, deuterium order parameter, and gauche conformation analyses. Furthermore, IPA bilayers possess a higher area compressibility modulus, molecular tilt modulus, and effective bending rigidity than PC systems. The variation of hydrophilic groups of IPA also leads to fewer hydrogen bonds on the membrane surface and smaller electrostatic potentials for the biomimetic bilayer. The non-covalently linked head groups of IPA further decouple alkyl tilting and surface water retention. The combined results reveal the importance of hydrophilic groups of amphiphiles on modulating the membrane properties, which also provides insights for designs of biomimetic membranes.
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Cordeiro RM. Molecular Structure and Permeability at the Interface between Phase-Separated Membrane Domains. J Phys Chem B 2018; 122:6954-6965. [DOI: 10.1021/acs.jpcb.8b03406] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rodrigo M. Cordeiro
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Avenida dos Estados 5001, CEP 09210-580 Santo André, SP, Brazil
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Deng Y, Ling J, Li MH. Physical stimuli-responsive liposomes and polymersomes as drug delivery vehicles based on phase transitions in the membrane. NANOSCALE 2018; 10:6781-6800. [PMID: 29616274 DOI: 10.1039/c8nr00923f] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This paper reviews liposomes with crystalline phase and polymersomes exhibiting crystalline and thermotropic liquid crystalline phases in the membrane. Intriguing morphologies of vesicles are described, including spherical, ellipsoidal and faceted vesicles, produced by a large variety of amphiphilic molecules and polymers with nematic phase, smectic phase or crystalline phase. It is highlighted how the phase transitions and the phase grain boundaries could be used ingeniously to destabilize the vesicular structure and to achieve cargo-release under the action of external stimulation. These liposomes and polymersomes are responsive to physical stimuli, such as temperature variation, shear stress, light illumination, and magnetic and electric fields. These stimuli-responsive properties make them promising candidates as new smart drug delivery systems.
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Affiliation(s)
- Yangwei Deng
- Chimie ParisTech, PSL University Paris, CNRS, Institut de Recherche de Chimie Paris, UMR8247, 11 rue Pierre et Marie Curie, 75005 Paris, France.
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Youssefian S, Rahbar N, Lambert CR, Van Dessel S. Variation of thermal conductivity of DPPC lipid bilayer membranes around the phase transition temperature. J R Soc Interface 2018; 14:rsif.2017.0127. [PMID: 28539484 PMCID: PMC5454301 DOI: 10.1098/rsif.2017.0127] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 04/26/2017] [Indexed: 01/28/2023] Open
Abstract
Given their amphiphilic nature and chemical structure, phospholipids exhibit a strong thermotropic and lyotropic phase behaviour in an aqueous environment. Around the phase transition temperature, phospholipids transform from a gel-like state to a fluid crystalline structure. In this transition, many key characteristics of the lipid bilayers such as structure and thermal properties alter. In this study, we employed atomistic simulation techniques to study the structure and underlying mechanisms of heat transfer in dipalmitoylphosphatidylcholine (DPPC) lipid bilayers around the fluid–gel phase transformation. To investigate this phenomenon, we performed non-equilibrium molecular dynamics simulations for a range of different temperature gradients. The results show that the thermal properties of the DPPC bilayer are highly dependent on the temperature gradient. Higher temperature gradients cause an increase in the thermal conductivity of the DPPC lipid bilayer. We also found that the thermal conductivity of DPPC is lowest at the transition temperature whereby one lipid leaflet is in the gel phase and the other is in the liquid crystalline phase. This is essentially related to a growth in thermal resistance between the two leaflets of lipid at the transition temperature. These results provide significant new insights into developing new thermal insulation for engineering applications.
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Affiliation(s)
- Sina Youssefian
- Civil and Environmental Engineering Department, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - Nima Rahbar
- Civil and Environmental Engineering Department, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - Christopher R Lambert
- Chemistry and Biochemistry Department, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
| | - Steven Van Dessel
- Civil and Environmental Engineering Department, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA
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Kang M, Lee B, Leal C. Three-Dimensional Microphase Separation and Synergistic Permeability in Stacked Lipid-Polymer Hybrid Membranes. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2017; 29:9120-9132. [PMID: 31097879 PMCID: PMC6516788 DOI: 10.1021/acs.chemmater.7b02845] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We present new structures of soft-material thin films that augment the functionality of substrate-mediated delivery systems. A hybrid material composed of phospholipids and block copolymers adopts a multilayered membrane structure supported on a solid surface. The hybrid films comprise intentional intramembrane heterogeneities that register across multilayers. These stacked domains convey unprecedented enhancement and control of permeability of solutes across micrometer-thick films. Using grazing incidence X-ray scattering, phase contrast atomic force microscopy, and confocal microscopy, we observed that in each lamella, lipid and polymers partition unevenly within the membrane plane segregating into lipid- or polymer-rich domains. Interestingly, we found evidence that like-domains align in registry across multilayers, thereby making phase separation three-dimensional. Phase boundaries exist over extended length scales to compensate the height mismatch between lipid and polymer molecules. We show that microphase separation in hybrid films can be exploited to augment the capability of drug-eluting substrates. Lipid-polymer hybrid films loaded with paclitaxel show synergistic permeability of drug compared to single-component counterparts. We present a thorough structural study of stacked lipid-polymer hybrid membranes and propose that the presence of registered domains and domain boundaries impart enhanced drug release functionality. This work offers new perspectives in designing thin films for controlled delivery applications.
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Affiliation(s)
- Minjee Kang
- Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Byeongdu Lee
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Cecilia Leal
- Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
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Sun L, Böckmann RA. Membrane phase transition during heating and cooling: molecular insight into reversible melting. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 47:151-164. [PMID: 28725998 DOI: 10.1007/s00249-017-1237-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/18/2017] [Accepted: 06/28/2017] [Indexed: 11/25/2022]
Abstract
With increasing temperature, lipid bilayers undergo a gel-fluid phase transition, which plays an essential role in many physiological phenomena. In the present work, this first-order phase transition was investigated for variable heating and cooling rates for a dipalmitoylphosphatidylcholine (DPPC) lipid bilayer by means of atomistic molecular dynamics simulations. Alternative methods to track the melting temperature [Formula: see text] are compared. The resulting [Formula: see text] is shown to be independent of the scan rate for small heating rates (0.05-0.3 K/ns) implying reversible melting, and increases for larger heating (0.3-4 K/ns) or cooling rates (2-0.1 K/ns). The reported dependency of the melting temperature on the heating rate is in perfect agreement with a two-state kinetic rate model as suggested previously. Expansion and shrinkage, as well as the dynamics of melting seeds is described. The simulations further exhibit a relative shift between melting seeds in opposing membrane leaflets as predicted from continuum elastic theory.
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Affiliation(s)
- Liping Sun
- Computational Biology, Department of Biology, Friedrich-Alexander-University of Erlangen-Nürnberg, Staudtstrasse 5, Erlangen, 91058, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander-University of Erlangen-Nürnberg, Staudtstrasse 5, Erlangen, 91058, Germany.
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