1
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Pandey Y, Ingold A, Kumar N, Zenobi R. Nanoscale visualization of phase separation in binary supported lipid monolayer using tip-enhanced Raman spectroscopy. NANOSCALE 2024; 16:10578-10583. [PMID: 38767416 PMCID: PMC11154864 DOI: 10.1039/d4nr00816b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/05/2024] [Indexed: 05/22/2024]
Abstract
Supported lipid membranes are an important model system to study the phase separation behavior at the nanoscale. However, the conventional nanoanalytical tools often fail to provide reliable chemical characterization of the phase separated domains in a non-destructive and label-free manner. This study demonstrates the application of scanning tunneling microscopy-based tip-enhanced Raman spectroscopy (TERS) to study the nanoscale phase separation in supported d62-DPPC : DOPC lipid monolayers. Hyperspectral TERS imaging successfully revealed a clear segregation of the d62-DPPC-rich and DOPC-rich domains. Interestingly, nanoscale deposits of d62-DPPC were observed inside the DOPC-rich domains and vice versa. High-resolution TERS imaging also revealed the presence of a 40-120 nm wide interfacial region between the d62-DPPC-rich and DOPC-rich domains signifying a smooth transition rather than a sharp boundary between them. The novel insights obtained in this study demonstrate the effectiveness of TERS in studying binary lipid monolayers at the nanoscale.
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Affiliation(s)
- Yashashwa Pandey
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
| | - Andrea Ingold
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
| | - Naresh Kumar
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
| | - Renato Zenobi
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 3, 8093 Zurich, Switzerland.
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2
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Fellows AP, John B, Wolf M, Thämer M. Spiral packing and chiral selectivity in model membranes probed by phase-resolved sum-frequency generation microscopy. Nat Commun 2024; 15:3161. [PMID: 38605056 PMCID: PMC11009297 DOI: 10.1038/s41467-024-47573-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 04/04/2024] [Indexed: 04/13/2024] Open
Abstract
Since the lipid raft model was developed at the end of the last century, it became clear that the specific molecular arrangements of phospholipid assemblies within a membrane have profound implications in a vast range of physiological functions. Studies of such condensed lipid islands in model systems using fluorescence and Brewster angle microscopies have shown a wide range of sizes and morphologies, with suggestions of substantial in-plane molecular anisotropy and mesoscopic structural chirality. Whilst these variations can significantly alter many membrane properties including its fluidity, permeability and molecular recognition, the details of the in-plane molecular orientations underlying these traits remain largely unknown. Here, we use phase-resolved sum-frequency generation microscopy on model membranes of mixed chirality phospholipid monolayers to fully determine the three-dimensional molecular structure of the constituent micron-scale condensed domains. We find that the domains possess curved molecular directionality with spiralling mesoscopic packing, where both the molecular and spiral turning directions depend on the lipid chirality, but form structures clearly deviating from mirror symmetry for different enantiomeric mixtures. This demonstrates strong enantioselectivity in the domain growth process and indicates fundamental thermodynamic differences between homo- and heterochiral membranes, which may be relevant in the evolution of homochirality in all living organisms.
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Affiliation(s)
| | - Ben John
- Fritz-Haber-Institute of the Max-Planck-Society, Berlin, Germany
| | - Martin Wolf
- Fritz-Haber-Institute of the Max-Planck-Society, Berlin, Germany
| | - Martin Thämer
- Fritz-Haber-Institute of the Max-Planck-Society, Berlin, Germany.
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3
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Henderson RDE, Mei N, Xu Y, Gaikwad R, Wettig S, Leonenko Z. Nanoscale Structure of Lipid-Gemini Surfactant Mixed Monolayers Resolved with AFM and KPFM Microscopy. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:572. [PMID: 38607107 PMCID: PMC11013119 DOI: 10.3390/nano14070572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/13/2024]
Abstract
Drug delivery vehicles composed of lipids and gemini surfactants (GS) are promising in gene therapy. Tuning the composition and properties of the delivery vehicle is important for the efficient load and delivery of DNA fragments (genes). In this paper, we studied novel gene delivery systems composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dipalmitoyl-sn-3-phosphocholine (DPPC), and GS of the type N,N-bis(dimethylalkyl)-α,ω-alkanediammonium dibromide at different ratios. The nanoscale properties of the mixed DOPC-DPPC-GS monolayers on the surface of the gene delivery system were studied using atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). We demonstrate that lipid-GS mixed monolayers result in the formation of nanoscale domains that vary in size, height, and electrical surface potential. We show that the presence of GS can impart significant changes to the domain topography and electrical surface potential compared to monolayers composed of lipids alone.
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Affiliation(s)
- Robert D. E. Henderson
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (R.D.E.H.); (N.M.); (Y.X.)
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Nanqin Mei
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (R.D.E.H.); (N.M.); (Y.X.)
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Yue Xu
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (R.D.E.H.); (N.M.); (Y.X.)
| | - Ravi Gaikwad
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (R.D.E.H.); (N.M.); (Y.X.)
| | - Shawn Wettig
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
- School of Pharmacy, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Zoya Leonenko
- Department of Physics & Astronomy, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (R.D.E.H.); (N.M.); (Y.X.)
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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4
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Yu CC, Seki T, Chiang KY, Wang Y, Bonn M, Nagata Y. Depth-profiling alkyl chain order in unsaturated lipid monolayers on water. J Chem Phys 2024; 160:114902. [PMID: 38506293 DOI: 10.1063/5.0190519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 02/28/2024] [Indexed: 03/21/2024] Open
Abstract
Unsaturated lipids with C=C groups in their alkyl chains are widely present in the cell membrane and food. The C=C groups alter the lipid packing density, membrane stability, and persistence against lipid oxidation. Yet, molecular-level insights into the structure of the unsaturated lipids remain scarce. Here, we probe the molecular structure and organization of monolayers of unsaturated lipids on the water surface using heterodyne-detected sum-frequency generation (HD-SFG) spectroscopy. We vary the location of the C=C in the alkyl chain and find that at high lipid density, the location of the C=C group affects neither the interfacial water organization nor the tail of the alkyl chain. Based on this observation, we use the C=C stretch HD-SFG response to depth-profile the alkyl chain conformation of the unsaturated lipid. We find that the first 1/3 of carbon atoms from the headgroup are relatively rigid, oriented perpendicular to the surface. In contrast, the remaining carbon atoms can be approximated as free rotators, introducing the disordering of the alkyl chains.
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Affiliation(s)
- Chun-Chieh Yu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Takakazu Seki
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, 036-8561 Aomori, Japan
| | - Kuo-Yang Chiang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yongkang Wang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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5
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Li B, Ma Y, Han X, Hu P, Lu X. Enhanced Sum Frequency Generation for Monolayers on Au Relative to Silica: Local Field Factors and SPR Effect. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:659-667. [PMID: 36580605 DOI: 10.1021/acs.langmuir.2c03016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Using metals as signal magnified substrates, surface plasmon-enhanced sum frequency generation (SFG) vibrational spectroscopy is a promising technique to probe weak molecular-level signals at surfaces and interfaces. In this study, the vibrational signals of the n-alkane monolayer on the gold (Au) and silica substrates are investigated using the broadband femtosecond SFG. The enhancement factors are discovered to be up to ∼1076 and ∼31 for the methyl symmetric and asymmetric stretching (ss and as) modes of the monolayer, respectively. By systematically analyzing the second-order nonlinear susceptibility tensor components (χijks), the Fresnel coefficients (Fijks), and the surface plasmon resonance (SPR) effect, we find that the interplay between Fijk and χijk terms and the SPR effect dominate the SFG signal enhancement. Our study reveals that the relative contributions of different influencing factors (i.e., Fresnel coefficients and SPR) to the SFG signal enhancement provide an approach to interpreting enhanced SFG vibrational signals detected from probe molecules on distinct substrates and may finally guide the design of the experimental methodology to improve the detection sensitivity and signal-to-noise ratio.
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Affiliation(s)
- Bolin Li
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory (HMFL), Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences, Hefei, Anhui230031, P. R. China
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
| | - Yonghao Ma
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
| | - Xiaofeng Han
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
| | - Pengcheng Hu
- School of Medical Imaging, Xuzhou Medical College, Xuzhou, Jiangsu221004, China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
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6
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Liposomes encapsulating methylene blue and acridine orange: An approach for phototherapy of skin cancer. Colloids Surf B Biointerfaces 2022; 220:112901. [DOI: 10.1016/j.colsurfb.2022.112901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 09/22/2022] [Accepted: 10/01/2022] [Indexed: 11/05/2022]
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7
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Golbek TW, Harper BJ, Harper SL, Baio JE. Shape-dependent gold nanoparticle interactions with a model cell membrane. Biointerphases 2022; 17:061003. [PMID: 36347646 PMCID: PMC9646251 DOI: 10.1116/6.0002183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 11/11/2022] Open
Abstract
Customizable gold nanoparticle platforms are motivating innovations in drug discovery with massive therapeutic potential due to their biocompatibility, stability, and imaging capabilities. Further development requires the understanding of how discrete differences in shape, charge, or surface chemistry affect the drug delivery process of the nanoparticle. The nanoparticle shape can have a significant impact on nanoparticle function as this can, for example, drastically change the surface area available for modifications, such as surface ligand density. In order to investigate the effects of nanoparticle shape on the structure of cell membranes, we directly probed nanoparticle-lipid interactions with an interface sensitive technique termed sum frequency generation (SFG) vibrational spectroscopy. Both gold nanostars and gold nanospheres with positively charged ligands were allowed to interact with a model cell membrane and changes in the membrane structure were directly observed by specific SFG vibrational modes related to molecular bonds within the lipids. The SFG results demonstrate that the +Au nanostars both penetrated and impacted the ordering of the lipids that made up the membrane, while very little structural changes to the model membrane were observed by SFG for the +Au nanospheres interacting with the model membrane. This suggests that the +Au nanostars, compared to the +Au nanospheres, are more disruptive to a cell membrane. Our findings indicate the importance of shape in nanomaterial design and provide strong evidence that shape does play a role in defining nanomaterial-biological interactions.
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Affiliation(s)
| | - Bryan J Harper
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97330
| | - Stacey L Harper
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97330
| | - Joe E Baio
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97330
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8
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Navakauskas E, Niaura G, Strazdaite S. Effect of deuteration on a phosphatidylcholine lipid monolayer structure: New insights from vibrational sum-frequency generation spectroscopy. Colloids Surf B Biointerfaces 2022; 220:112866. [PMID: 36174490 DOI: 10.1016/j.colsurfb.2022.112866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/07/2022] [Accepted: 09/19/2022] [Indexed: 10/14/2022]
Abstract
We used vibrational sum-frequency generation (VSFG) spectroscopy to elucidate the possible effect of various levels of isotopic substitution (H/D) on the properties of the DPPC monolayer by probing DPPC/D2O interface. We found that deuteration of the choline group has a great impact on monolayer properties, while monolayers with deuterated alkyl chains do not exhibit any differences under our experimental conditions. In addition, deuteration of the choline group strongly affected the hydration of the phosphate group. We showed by probing symmetric stretching vibration of phosphate group that denser packing only slightly reduced the hydration of DPPC-d13 and DPPC-d75 monolayers. Moreover, addition of calcium ions, which generally cause a marked dehydration of the lipid monolayer, had no effect on lipid monolayers with deuterated choline group. We proposed that one way to explain this experimental finding could be deuteration induced changes in the structure of lipid's choline group, resulting in a well-hydrated but Ca2+ ion blocking structure. These results have important implications for various spectroscopic techniques, which commonly use deuteration of phospholipids to circumvent overlapping between vibrational bands.
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Affiliation(s)
- Edvinas Navakauskas
- Department of Organic Chemistry, Center for Physical Sciences and Technology (FTMC), Saulėtekis ave. 3, LT-10257 Vilnius, Lithuania
| | - Gediminas Niaura
- Department of Organic Chemistry, Center for Physical Sciences and Technology (FTMC), Saulėtekis ave. 3, LT-10257 Vilnius, Lithuania.
| | - Simona Strazdaite
- Department of Organic Chemistry, Center for Physical Sciences and Technology (FTMC), Saulėtekis ave. 3, LT-10257 Vilnius, Lithuania
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9
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Jurak M, Szafran K, Cea P, Martín S. Characteristics of Phospholipid-Immunosuppressant-Antioxidant Mixed Langmuir-Blodgett Films. J Phys Chem B 2022; 126:6936-6947. [PMID: 36066119 PMCID: PMC9483916 DOI: 10.1021/acs.jpcb.2c03300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hemocompatibility is one of the major criteria for the successful cardiovascular applicability of novel biomaterials. In this context, monolayers of certain biomolecules can be used to improve surface biocompatibility. To this end, biocoatings incorporating a phospholipid (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC), an immunosuppressant (cyclosporine A, CsA), and an antioxidant material (lauryl gallate, LG) were fabricated by depositing Langmuir films onto gold or mica substrates using the Langmuir-Blodgett (LB) technique. These LB monolayers were thoroughly characterized by means of quartz crystal microbalance (QCM), atomic force microscopy (AFM), cyclic voltammetry (CV), and contact angle (CA) measurements. The obtained results indicate that the properties of these LB films are modulated by the monolayer composition. The presence of LG in the three-component systems (DOPC-CsA-LG) increases the molecular packing and the surface coverage of the substrate, which affects the wettability of the biocoating. From the different compositions studied here, we conclude that DOPC-CsA-LG monolayers with a DOPC/CsA ratio of 1:1 and LG molar fractions of 0.50 and 0.75 exhibit improved surface biocompatible characteristics. These results open up new perspectives on our knowledge and better understanding of phenomena at the biomaterial/host interface.
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Affiliation(s)
- Małgorzata Jurak
- Department of Interfacial Phenomena, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University, 20031 Lublin, Poland
| | - Klaudia Szafran
- Department of Interfacial Phenomena, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University, 20031 Lublin, Poland
| | - Pilar Cea
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.,Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain.,Laboratorio de Microscopias Avanzadas, LMA, C/Mariano Esquilor s/n, 50018 Zaragoza, Spain
| | - Santiago Martín
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain.,Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain.,Laboratorio de Microscopias Avanzadas, LMA, C/Mariano Esquilor s/n, 50018 Zaragoza, Spain
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10
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Zhou Z, Lakey PSJ, von Domaros M, Wise N, Tobias DJ, Shiraiwa M, Abbatt JPD. Multiphase Ozonolysis of Oleic Acid-Based Lipids: Quantitation of Major Products and Kinetic Multilayer Modeling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7716-7728. [PMID: 35671499 DOI: 10.1021/acs.est.2c01163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Commonly found in atmospheric aerosols, cooking oils, and human sebum, unsaturated lipids rapidly decay upon exposure to ozone, following the Criegee mechanism. Here, the gas-surface ozonolysis of three oleic acid-based compounds was studied in a reactor and indoors. Under dry conditions, quantitative product analyses by 1H NMR indicate up to 79% molar yield of stable secondary ozonides (SOZs) in oxidized triolein and methyl oleate coatings. Elevated relative humidity (RH) significantly suppresses the SOZ yields, enhancing the formation of condensed-phase aldehydes and volatile C9 products. Along with kinetic parameters informed by molecular dynamics simulations, these results were used as constraints in a kinetic multilayer model (KM-GAP) simulating triolein ozonolysis. Covering a wide range of coating thicknesses and ozone levels, the model predicts a much faster decay near the gas-lipid interface compared to the bulk. Although the dependence of RH on SOZ yields is well predicted, the model overestimates the production of H2O2 and aldehydes. With negligible dependence on RH, the product composition for oxidized oleic acid is substantially affected by a competitive reaction between Criegee intermediates (CIs) and carboxylic acids. The resulting α-acyloxyalkyl hydroperoxides (α-AAHPs) have much higher molar yields (29-38%) than SOZs (12-16%). Overall, the ozone-lipid chemistry could affect the indoor environment through "crust" accumulation on surfaces and volatile organic compound (VOC) emission. In the atmosphere, the peroxide formation and changes in particle hygroscopicity may have effects on climate. The related health impacts are also discussed.
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Affiliation(s)
- Zilin Zhou
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
| | - Pascale S J Lakey
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Michael von Domaros
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Natsuko Wise
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Douglas J Tobias
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
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11
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The lung surfactant activity probed with molecular dynamics simulations. Adv Colloid Interface Sci 2022; 304:102659. [PMID: 35421637 DOI: 10.1016/j.cis.2022.102659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 03/18/2022] [Accepted: 03/31/2022] [Indexed: 01/17/2023]
Abstract
The surface of pulmonary alveolar subphase is covered with a mixture of lipids and proteins. This lung surfactant plays a crucial role in lung functioning. It shows a complex phase behavior which can be altered by the interaction with third molecules such as drugs or pollutants. For studying multicomponent biological systems, it is of interest to couple experimental approach with computational modelling yielding atomic-scale information. Simple two, three, or four-component model systems showed to be useful for getting more insight in the interaction between lipids, lipids and proteins or lipids and proteins with drugs and impurities. These systems were studied theoretically using molecular dynamic simulations and experimentally by means of the Langmuir technique. A better understanding of the structure and behavior of lung surfactants obtained from this research is relevant for developing new synthetic surfactants for efficient therapies, and may contribute to public health protection.
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12
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Qiao L, Chen Z, Takada C, Chiba H, Inoue KI, Hui SP, Ye S. Quantitative Evaluation on the Degradation Process of the Pulmonary Surfactant Monolayer When Exposed to Low-Level Ozone of Ambient Environment. Anal Chem 2022; 94:8651-8658. [PMID: 35605232 DOI: 10.1021/acs.analchem.2c00576] [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
Ozone is a potent environmental oxidant with high chemical reactivity and is present in the ambient environment at a low level of a few tens of ppb. However, only limited information is known about low-level ozone's influence on the respiratory system. In the present study, we systematically investigated the degradation of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), which is one of the major components of the pulmonary surfactant (PS), enabling breath function of the lung exposed to low ambient-level ozone (40 ± 10 ppb). Using the liquid chromatography-mass spectrometry technique combined with the Langmuir-Blodgett approach, we first tracked the degradation process of POPC molecules by determining the degradation products during exposure to the ambient environment. As a result, we found that the POPC molecules can be readily degraded from the C═C moiety in 45 min, yielding an aldehyde-type product of 1-palmitoyl-2-(9'-oxo-nonanoyl)-sn-glycero-3-phosphocholine (POnPC) and a trace amount of an acid-type one of 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PAzPC), as well as a pair of secondary ozonide (SOZ) isomers. Furthermore, with prolonged exposure, the SOZ stayed constant but the yield of PAzPC significantly increased with the decrease in POnPC. The low-level ozone-induced oxidation mechanisms for unsaturated lipids are discussed based on the quantitative analyses of these experimental observations. The present results demonstrate that the ground-level ozone is strong enough to induce dramatic oxidation damage to the unsaturated lipids of the PS. These oxidized species may trigger the lung's inflammatory response and be used as biomarkers for oxidative stress and inflammation.
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Affiliation(s)
- Lin Qiao
- Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Zhen Chen
- Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Chunji Takada
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Hitoshi Chiba
- Department of Nutrition, Sapporo University of Health Sciences, Sapporo 007-0894, Japan
| | - Ken-Ichi Inoue
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Shu-Ping Hui
- Faculty of Health Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Shen Ye
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.,Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan
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13
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Sofińska K, Lupa D, Chachaj-Brekiesz A, Czaja M, Kobierski J, Seweryn S, Skirlińska-Nosek K, Szymonski M, Wilkosz N, Wnętrzak A, Lipiec E. Revealing local molecular distribution, orientation, phase separation, and formation of domains in artificial lipid layers: Towards comprehensive characterization of biological membranes. Adv Colloid Interface Sci 2022; 301:102614. [PMID: 35190313 DOI: 10.1016/j.cis.2022.102614] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 01/01/2023]
Abstract
Lipids, together with molecules such as DNA and proteins, are one of the most relevant systems responsible for the existence of life. Selected lipids are able to assembly into various organized structures, such as lipid membranes. The unique properties of lipid membranes determine their complex functions, not only to separate biological environments, but also to participate in regulatory functions, absorption of nutrients, cell-cell communication, endocytosis, cell signaling, and many others. Despite numerous scientific efforts, still little is known about the reason underlying the variability within lipid membranes, and its biochemical significance. In this review, we discuss the structural complexity of lipid membranes, as well as the importance to simplify studied systems in order to understand phenomena occurring in natural, complex membranes. Such systems require a model interface to be analyzed. Therefore, here we focused on analytical studies of artificial systems at various interfaces. The molecular structure of lipid membranes, specifically the nanometric thickens of molecular bilayer, limits in a major extent the choice of highly sensitive methods suitable to study such structures. Therefore, we focused on methods that combine high sensitivity, and/or chemical selectivity, and/or nanometric spatial resolution, such as atomic force microscopy, nanospectroscopy (tip-enhanced Raman spectroscopy, infrared nanospectroscopy), phase modulation infrared reflection-absorption spectroscopy, sum-frequency generation spectroscopy. We summarized experimental and theoretical approaches providing information about molecular structure and composition, lipid spatial distribution (phase separation), organization (domain shape, molecular orientation) of lipid membranes, and real-time visualization of the influence of various molecules (proteins, drugs) on their integrity. An integral part of this review discusses the latest achievements in the field of lipid layer-based biosensors.
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14
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Pereira LS, Camacho SA, Almeida AM, Gonçalves RS, Caetano W, DeWolf C, Aoki PH. Mechanisms of hypericin incorporation to explain the photooxidation outcomes in phospholipid biomembrane models. Chem Phys Lipids 2022; 244:105181. [DOI: 10.1016/j.chemphyslip.2022.105181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/14/2022] [Accepted: 02/10/2022] [Indexed: 11/03/2022]
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15
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Zaborowska M, Dziubak D, Matyszewska D, Sek S, Bilewicz R. Designing a Useful Lipid Raft Model Membrane for Electrochemical and Surface Analytical Studies. Molecules 2021; 26:5483. [PMID: 34576954 PMCID: PMC8467995 DOI: 10.3390/molecules26185483] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 12/04/2022] Open
Abstract
A model biomimetic system for the study of protein reconstitution or drug interactions should include lipid rafts in the mixed lipid monolayer, since they are usually the domains embedding membrane proteins and peptides. Four model lipid films composed of three components: 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), cholesterol (Chol) and sphingomyelin (SM) mixed in different molar ratios were proposed and investigated using surface pressure measurements and thermodynamic analysis of the monolayers at the air-water interface and imaged by Brewster angle microscopy. The ternary monolayers were transferred from the air-water onto the gold electrodes to form bilayer films and were studied for the first time by electrochemical methods: alternative current voltammetry and electrochemical impedance spectroscopy and imaged by atomic force microscopy. In excess of DOPC, the ternary systems remained too liquid for the raft region to be stable, while in the excess of cholesterol the layers were too solid. The layers with SM in excess lead to the formation of Chol:SM complexes but the amount of the fluid matrix was very low. The equimolar content of the three components lead to the formation of a stable and well-organized assembly with well-developed raft microdomains of larger thickness, surrounded by the more fluid part of the bilayer. The latter is proposed as a convenient raft model membrane for further physicochemical studies of interactions with drugs or pollutants or incorporation of membrane proteins.
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Affiliation(s)
| | - Damian Dziubak
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02089 Warsaw, Poland; (D.D.); (S.S.)
| | - Dorota Matyszewska
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02089 Warsaw, Poland; (D.D.); (S.S.)
| | - Slawomir Sek
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02089 Warsaw, Poland; (D.D.); (S.S.)
| | - Renata Bilewicz
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02093 Warsaw, Poland;
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Advantageous/Unfavorable Effect of Quercetin on the Membranes of SK-N-SH Neuroblastoma Cells. Molecules 2021; 26:molecules26164945. [PMID: 34443533 PMCID: PMC8397999 DOI: 10.3390/molecules26164945] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 11/27/2022] Open
Abstract
Quercetin is a polyphenolic compound, the effects of which raise scientists’ doubts. The results of many experiments show that it has anticancer, antiinflammatory, and antioxidant properties, while other studies indicate its pro-oxidative and cytotoxic action. This compound can react with reactive oxygen species, and due to its chemical properties, it can be found in the hydrophobic-hydrophilic area of cells. These features of quercetin indicate that its action in cells will be associated with the modification of membranes and its participation in maintaining the redox balance. Therefore, this study distinguishes these two mechanisms and determines whether they are important for cell function. We check: (1) Whether the selected concentrations of quercetin are cytotoxic and destructive for SK-N-SH cell membranes (MTT, LDH, MDA tests) in situations with and without the applied oxidative stress; (2) what is the level of changes in the structural/mechanical properties of the lipid part of the membranes of these cells due to the presence of polyphenol molecules; and (3) whether the antioxidative action of quercetin protects the membrane against its modification. Our results show that changes in the stiffness/elasticity of the lipid part of the membrane constitute the decisive mechanism of action of quercetin, potentially influencing cellular processes whose initial stages are associated with membranes (e.g., reception of signals from the environment, transport).
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Inoue KI, Fujimoto K, Takada C, Ge A, Ye S. Effect of Head Group on Low-Level Ozone Oxidation of Unsaturated Phospholipids on a Water Surface. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200250] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ken-ichi Inoue
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kana Fujimoto
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Chunji Takada
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Aimin Ge
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Shen Ye
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
- Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan
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18
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Moreira LG, Almeida AM, Camacho SA, Estevão BM, Oliveira ON, Aoki PHB. Chain Cleavage of Bioinspired Bacterial Membranes Photoinduced by Eosin Decyl Ester. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:9578-9585. [PMID: 32672975 DOI: 10.1021/acs.langmuir.0c01600] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photodynamic therapy (PDT) is promising for bacterial inactivation since cellular internalization of photosensitizers (PS) is not crucial for the treatment effectiveness. Photoinduced damage in the lipid envelope may already induce microbial inactivation, which requires PS capable of easily penetrating into the membrane. Herein, we report on the insertion of the PS eosin decyl ester (EosDec) into Langmuir films of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DOPG), and cardiolipin (CLP) used as mimetic systems of bacterial membranes. Surface pressure isotherms and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) indicated that the hydrophobic nature of EosDec favored deeper penetration in all the phospholipid monolayers. The incorporation of EosDec led to monolayer expansion, especially in the anionic DOPG and CLP owing to repulsive electrostatic interactions, and induced disorder in the lipid chains. Light irradiation of DOPE, DOPG, and CLP monolayers containing EosDec increased the rate of material loss to the subphase, which is attributed to cleavage of lipid chains triggered by contact-dependent reactions between excited states of EosDec and lipid unsaturations. The latter is key for membrane permeabilization and efficiency in microbial inactivation.
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Affiliation(s)
- Lucas G Moreira
- School of Sciences, Humanities and Languages, São Paulo State University (UNESP), Assis, SP 19806-900, Brazil
| | - Alexandre M Almeida
- School of Sciences, Humanities and Languages, São Paulo State University (UNESP), Assis, SP 19806-900, Brazil
| | - Sabrina A Camacho
- School of Sciences, Humanities and Languages, São Paulo State University (UNESP), Assis, SP 19806-900, Brazil
- IFSC, São Carlos Institute of Physics, University of São Paulo (USP), São Carlos, SP 13566-590, Brazil
| | - Bianca M Estevão
- IFSC, São Carlos Institute of Physics, University of São Paulo (USP), São Carlos, SP 13566-590, Brazil
- Department of Chemistry, State University of Maringá (UEM), Maringá, PR 87020-900, Brazil
| | - Osvaldo N Oliveira
- IFSC, São Carlos Institute of Physics, University of São Paulo (USP), São Carlos, SP 13566-590, Brazil
| | - Pedro H B Aoki
- School of Sciences, Humanities and Languages, São Paulo State University (UNESP), Assis, SP 19806-900, Brazil
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19
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Inoue KI, Takada C, Wang L, Morita A, Ye S. In Situ Monitoring of the Unsaturated Phospholipid Monolayer Oxidation in Ambient Air by HD-SFG Spectroscopy. J Phys Chem B 2020; 124:5246-5250. [PMID: 32478516 DOI: 10.1021/acs.jpcb.0c03408] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pulmonary surfactant monolayer is indispensable for the respiratory system. Recently, it was reported that some unsaturated lipids of the pulmonary surfactants are oxidized by low-level ozone in ambient air. However, the molecular-level understanding of the reaction mechanism is still limited due to technical difficulties. We applied heterodyne-detected sum frequency generation (HD-SFG) spectroscopy to probe the reaction process of an unsaturated phospholipid monolayer (1-palmitoyl-2-oleoyl-glycero-3-phosphocholine, POPC), which is one of the major lipids in the pulmonary surfactant, under low-level ozone (30 ± 5 ppb). The HD-SFG spectroscopy realized the accurate peak assignments of the spectra and the identification of molecular species with high sensitivity, which were impossible with previous measurements. The time-resolved spectra indicated that the C═C moiety in the unsaturated alkyl chain is selectively oxidized by ozone with a time constant of 22 ± 3 min by first-order reaction kinetics. Furthermore, it was revealed for the first time that the reaction product of the POPC monolayer under low-level ozone is not the carboxylic form but the aldehyde form based on the vibrational spectroscopy results. The present study has deepened our molecular-level understanding of the oxidation mechanism of unsaturated lipids that are widely found in many biological systems.
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Affiliation(s)
- Ken-Ichi Inoue
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Chunji Takada
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Lin Wang
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.,Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan
| | - Akihiro Morita
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.,Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan
| | - Shen Ye
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.,Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan
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20
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Camacho SA, Kobal MB, Almeida AM, Toledo KA, Oliveira ON, Aoki PHB. Molecular-level effects on cell membrane models to explain the phototoxicity of gold shell-isolated nanoparticles to cancer cells. Colloids Surf B Biointerfaces 2020; 194:111189. [PMID: 32580142 DOI: 10.1016/j.colsurfb.2020.111189] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 12/21/2022]
Abstract
Metallic nanoparticles are promising agents for photothermal cancer therapy (PTT) owing to their photostability and efficient light-to-heat conversion, but their possible aggregation remains an issue. In this paper, we report on the photoinduced heating of gold shell-isolated nanoparticles (AuSHINs) in in vitro experiments to kill human oropharyngeal (HEp-2) and breast (BT-474 and MCF-7) carcinoma cells, with cell viability reducing below 50 % with 2.2 × 1012 AuSHINs/mL and 6 h of incubation. This toxicity to cancer cells is significantly higher than in previous works with gold nanoparticles. Considering the AuSHINs dimensions we hypothesize that cell uptake is not straightforward, and the mechanism of action involves accumulation on phospholipid membranes as the PTT target for photoinduced heating and subsequent generation of reactive oxygen species (ROS). Using Langmuir monolayers as simplified membrane models, we confirmed that AuSHINs have a larger effect on 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS), believed to represent cancer cell membranes, than on 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) taken as representative of healthy eukaryotic cells. In particular, data from polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) revealed an increased conformational order of DOPS tails due to the stronger adsorption of AuSHINs. Furthermore, light irradiation reduced the stability of AuSHINs containing DOPC and DOPS monolayers owing to oxidative reactions triggered by ROS upon photoinduced heating. Compared to DOPC, DOPS lost nearly twice as much material to the subphase, which is consistent with a higher rate of ROS formation in the vicinity of the DOPS monolayer.
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Affiliation(s)
- Sabrina A Camacho
- São Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil; São Carlos Institute of Physics, University of São Paulo (USP), CP 369, São Carlos, SP, 13566-590, Brazil
| | - Mirella B Kobal
- São Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil
| | - Alexandre M Almeida
- São Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil
| | - Karina A Toledo
- São Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil
| | - Osvaldo N Oliveira
- São Carlos Institute of Physics, University of São Paulo (USP), CP 369, São Carlos, SP, 13566-590, Brazil
| | - Pedro H B Aoki
- São Paulo State University (UNESP), School of Sciences, Humanities and Languages, Assis, SP, 19806-900, Brazil.
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21
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Almeida AM, Oliveira ON, Aoki PHB. Role of Toluidine Blue-O Binding Mechanism for Photooxidation in Bioinspired Bacterial Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16745-16751. [PMID: 31746210 DOI: 10.1021/acs.langmuir.9b03045] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The alarming increase in bacterial resistance to antibiotics has demanded new strategies for microbial inactivation, which include photodynamic therapy whose activity relies on the photoreaction damage to the microorganism membrane. Herein, the binding mechanisms of the photosensitizer toluidine blue-O (TBO) on simplified models of bacterial membrane with Langmuir monolayers of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DOPG) were correlated to the effects of the photoinduced lipid oxidation. Langmuir monolayers of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) were also used as a reference of mammalian membranes. The surface pressure isotherms combined with polarization-modulated infrared reflection absorption spectroscopy revealed that TBO expands DOPC, DOPE, and DOPG monolayers owing to electrostatic interactions with the negatively charged groups in the phospholipids, with a stronger adsorption on DOPG, which has a net surface charge. Light irradiation made the TBO-containing DOPC and DOPE monolayers less unstable as a result of the singlet oxygen (1O2) reaction with the chain unsaturation and hydroperoxide formation. In contrast, the decreased stability of the irradiated TBO-containing DOPG monolayer suggests the cleavage of carbon chains. The anionic nature of DOPG allowed a deeper penetration of TBO into the chain region, favoring contact-dependent reactions between the excited triplet state of TBO and lipid unsaturations or/and hydroperoxide groups, which is the key for the cleavage reactions and further membrane permeabilization.
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Affiliation(s)
- Alexandre M Almeida
- São Paulo State University (UNESP) , School of Sciences, Humanities and Languages , Assis , SP , 19806-900 , Brazil
| | - Osvaldo N Oliveira
- IFSC , São Carlos Institute of Physics, University of São Paulo (USP) , São Carlos , SP 13566-590 , Brazil
| | - Pedro H B Aoki
- São Paulo State University (UNESP) , School of Sciences, Humanities and Languages , Assis , SP , 19806-900 , Brazil
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22
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Dreier LB, Wolde-Kidan A, Bonthuis DJ, Netz RR, Backus EHG, Bonn M. Unraveling the Origin of the Apparent Charge of Zwitterionic Lipid Layers. J Phys Chem Lett 2019; 10:6355-6359. [PMID: 31568720 DOI: 10.1021/acs.jpclett.9b02587] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The structure of water molecules in contact with zwitterionic lipid molecules is of great biological relevance, because biological membranes are largely composed of such lipids. The interaction of the interfacial water molecules with the amphiphilic lipid molecules drives the formation of membranes and greatly influences various processes at the membrane surface, as the field that arises from the aligned interfacial water molecules masks the charges of the lipid headgroups from the approaching metabolites. To increase our understanding of the influence of water molecules on biological processes we study their structure at the interface using sum-frequency generation spectroscopy and molecular dynamics simulations. Interestingly, we find that water molecules at zwitterionic lipid molecules are mainly oriented by the field arising between the two oppositely charged molecular moieties within the lipid headgroups.
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Affiliation(s)
- Lisa B Dreier
- Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
- Graduate School Materials Science in Mainz , Staudingerweg 9 , 55128 Mainz , Germany
| | - Amanuel Wolde-Kidan
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Douwe Jan Bonthuis
- Institute of Theoretical and Computational Physics , Graz University of Technology , 8010 Graz , Austria
| | - Roland R Netz
- Fachbereich Physik , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany
| | - Ellen H G Backus
- Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
- Department of Physical Chemistry , University of Vienna , Währinger Strasse 42 , 1090 Vienna , Austria
| | - Mischa Bonn
- Max Planck Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
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23
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Bland HC, Moilanen JA, Ekholm FS, Paananen RO. Investigating the Role of Specific Tear Film Lipids Connected to Dry Eye Syndrome: A Study on O-Acyl-ω-hydroxy Fatty Acids and Diesters. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3545-3552. [PMID: 30712353 DOI: 10.1021/acs.langmuir.8b04182] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Dry eye syndrome (DES) is a prevalent disease in which the tear film homeostasis is compromised. One of the main causes of DES is thought to be an alteration in the composition of the outermost layer of the tear film, the tear film lipid layer (TFLL), resulting in an increased evaporation of water from the tear film and subsequent drying of the ocular surface. Recent studies have suggested that the specific TFLL lipids, namely, O-acyl-ω-hydroxy fatty acids (OAHFAs) and diesters (DiEs), may play a role in the development of DES. However, their specific connection to DES has remained largely unknown until now because of the lack of information on their biophysical properties and their role in the TFLL. Herein, we have addressed this issue by studying the biophysical properties and evaporation resistance of a library containing 10 synthetic analogues of TFLL OAHFAs and DiEs. Our results show how the variations of chain length and polar groups affect the phase behavior of these lipids at the tear film surface. In addition, the results revealed that the OAHFAs exhibiting a liquid-expanded to solid phase transition formed films with high evaporation resistance, whereas the DiEs were found to have no evaporation resistance. Altogether, our results shed new light on the role of the OAHFAs and DiEs in the TFLL and their connection to DES, suggesting that OAHFAs are likely a key lipid class in maintaining the TFLL evaporation resistance.
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Affiliation(s)
- Helena C Bland
- Department of Chemistry , University of Helsinki , P.O. Box 55, FI-00014 Helsinki , Finland
| | - Jukka A Moilanen
- Ophthalmology , University of Helsinki and Helsinki University Hospital , Haartmaninkatu 8 , FI-00290 Helsinki , Finland
| | - Filip S Ekholm
- Department of Chemistry , University of Helsinki , P.O. Box 55, FI-00014 Helsinki , Finland
| | - Riku O Paananen
- Ophthalmology , University of Helsinki and Helsinki University Hospital , Haartmaninkatu 8 , FI-00290 Helsinki , Finland
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Cutro AC, Disalvo EA, Frías MA. Effects of Phenylalanine on the Liquid-Expanded and Liquid-Condensed States of Phosphatidylcholine Monolayers. Lipid Insights 2019; 12:1178635318820923. [PMID: 30643419 PMCID: PMC6322106 DOI: 10.1177/1178635318820923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 11/29/2018] [Indexed: 11/25/2022] Open
Abstract
Background: Phenylalanine (Phe) is involved in physiological and pathological processes in cell membranes in which expanded and condensed states coexist. In this direction, it was reported that surface hydration is important for the binding affinity of the amino acid which significantly perturbs 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer structure and morphology. A deeper insight showed that Phe inserts in DPPC monolayer defects as a monomer at pH 5 and forms aggregates that adsorb to the membrane surface generating a reconfiguration of the lipid arrangement in areas of higher packing. This new arrangement in the monolayer causes the reorientation of dipoles of lipid and water molecules which is congruent with the dehydration and surface tension changes reported above. With this background, this article studies the affinity of Phe in liquid-expanded 1,2-dimyristoyl-sn-glycero-3 phosphocholine (LE DMPC) and liquid-condensed 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (LC DPPC) monolayers and their effects on membrane properties. Results: The adsorption of Phe can be described by a cooperative process in non-independent sites suggesting that Phe/lipid systems reorganize to form new structures at a high degree of coverage. Compressibility modulus and Brewster angle microscopy (BAM) images allow to propose that Phe causes a new phase in 1,2-dimyristoyl-sn-glycero-3 phosphocholine (DMPC) and DPPC. Conclusions: Phe imposes new arrangements in the lipid phase to form new structures with different compressibility behavior than lipid binary mixtures of DMPC and DPPC. Phe interaction with the LC and LE phases gives place to a process in which a synergistic effect between non-independent sites can be produced. These features of Phe/lipid interaction would be of great importance to understand the multiple effects of Phe on cell membranes.
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Affiliation(s)
- Andrea C Cutro
- Applied Biophysics and Food Research Center, Centro de Investigaciones en Biofísica Aplicada y Alimentos (CIBAAL), National University of Santiago del Estero and CONICET, Santiago del Estero, Argentina
| | - E Anibal Disalvo
- Applied Biophysics and Food Research Center, Centro de Investigaciones en Biofísica Aplicada y Alimentos (CIBAAL), National University of Santiago del Estero and CONICET, Santiago del Estero, Argentina
| | - María A Frías
- Applied Biophysics and Food Research Center, Centro de Investigaciones en Biofísica Aplicada y Alimentos (CIBAAL), National University of Santiago del Estero and CONICET, Santiago del Estero, Argentina
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25
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The phase and charge of milk polar lipid membrane bilayers govern their selective interactions with proteins as demonstrated with casein micelles. J Colloid Interface Sci 2019; 534:279-290. [DOI: 10.1016/j.jcis.2018.09.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/09/2018] [Accepted: 09/10/2018] [Indexed: 12/14/2022]
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26
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Stachowicz-Kuśnierz A, Cwiklik L, Korchowiec J, Rogalska E, Korchowiec B. The impact of lipid oxidation on the functioning of a lung surfactant model. Phys Chem Chem Phys 2018; 20:24968-24978. [PMID: 30239547 DOI: 10.1039/c8cp04496a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Apart from being responsible for sufficient pulmonary compliance and preventing alveolar collapse, lung surfactant (LS) also forms the first barrier for uptake of inhaled pathogens. As such it is susceptible to damage caused by various deleterious compounds present in air, e.g. oxidants capable of oxidizing unsaturated LS lipids. This study examines the consequences of oxidizing 20% of unsaturated lipids in an LS model: a mixed 1 : 1 DPPC : POPC monolayer. POxnoPC (1-palmitoyl-2-(9-oxo-nonanoyl)-sn-glycero-3-phosphocholine) is considered as the main oxidation product. Experimental surface pressure-area isotherms and polarization-modulation infrared reflection-absorption spectroscopy are employed to probe changes in the macroscopic properties of the unsaturated lipid monolayer induced by oxidation. Microscopic details of the influence of oxidation on the monolayer's phase behavior are elucidated by molecular dynamics simulations at varying lipid packing. We demonstrate that unsaturated lipid oxidation shifts the isotherm towards larger areas and advances monolayer collapse. This is caused by a reversal of the oxidized sn-2 chains of POxnoPC towards the subphase, driven by electrostatic interactions between the aldehyde, glycerin, and water. Increased lipid bulkiness, hindered transition to the LC phase, and transfer of oxidized chain terminals to the subphase have been identified as the most troublesome consequences of this process. They result in the reduction of monolayer stability and its capability to withstand high surface pressures. This may lead to uncontrolled and irreversible loss of lipids from the surface.
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Affiliation(s)
- A Stachowicz-Kuśnierz
- Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Krakow, Poland.
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Preface. J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2017.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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28
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Rudolphi-Skórska E, Filek M, Zembala M. The Effects of the Structure and Composition of the Hydrophobic Parts of Phosphatidylcholine-Containing Systems on Phosphatidylcholine Oxidation by Ozone. J Membr Biol 2017; 250:493-505. [PMID: 28799139 PMCID: PMC5613038 DOI: 10.1007/s00232-017-9976-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/05/2017] [Indexed: 12/30/2022]
Abstract
The degree of lipid unsaturation is a parameter used to describe membrane susceptibility to oxidation. This paper highlights the importance of double bond distribution in the hydrophobic parts of lipid layers. The problem was studied by determining the effects induced by ozone dissolved in an aqueous phase acting on layers of unsaturated cholines of various molecular structures, including bi-unsaturated (DOPC), mono-unsaturated (POPC) and natural origin (soy PC). The destructive effects of ozone were quantified as the ratio of areas per molecule, which corresponded to a 1 mN/m rise in the layer surface pressure for oxidized to non-oxidized lipids (A lift/A lift0 ). The experimental results showed different behaviours among the studied lipids. Layers of DOPC with both unsaturated fatty acyl chains exhibited the greatest disruption compared with that of PC extracted from soy, which maintained stability despite high degree of unsaturation. Mono-unsaturated ozonized layers of POPC did not exhibit any disruption, but their modified properties indicated structural changes caused by the appearance of oxidation products. The stability of mixed layers (of the same unsaturation degree as the soy PC) composed of DOPC and fully saturated lipid increased, however, not reaching the soy PC level. Comparisons of the behaviour of tested systems indicated that the fraction of lipids containing one saturated acyl chain is the parameter most important for stability of the oxidized layer. The stabilizing effects of the cholesterol admixture were also quantified. Results obtained for lipid layers were supported by measurements of liposome size, zeta potential and surface tension of liposome suspension.
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Affiliation(s)
- Elżbieta Rudolphi-Skórska
- Department of Biochemistry, Biophysics and Biotechnology, Institute of Biology, Pedagogical University, Podchorążych 2, 30-084 Cracow, Poland
| | - Maria Filek
- Department of Biochemistry, Biophysics and Biotechnology, Institute of Biology, Pedagogical University, Podchorążych 2, 30-084 Cracow, Poland
| | - Maria Zembala
- Department of Biochemistry, Biophysics and Biotechnology, Institute of Biology, Pedagogical University, Podchorążych 2, 30-084 Cracow, Poland
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Saito K, Peng Q, Qiao L, Wang L, Joutsuka T, Ishiyama T, Ye S, Morita A. Theoretical and experimental examination of SFG polarization analysis at acetonitrile–water solution surfaces. Phys Chem Chem Phys 2017; 19:8941-8961. [DOI: 10.1039/c6cp08856b] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polarization analysis of SFG spectroscopy is thoroughly examined in collaboration of SFG measurements and MD simulations.
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Affiliation(s)
- Kengo Saito
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Aoba-ku
- Japan
| | - Qiling Peng
- Institute for Catalysis
- Hokkaido University
- Kita-ku
- Japan
| | - Lin Qiao
- Institute for Catalysis
- Hokkaido University
- Kita-ku
- Japan
| | - Lin Wang
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Aoba-ku
- Japan
| | - Tatsuya Joutsuka
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Aoba-ku
- Japan
| | - Tatsuya Ishiyama
- Department of Applied Chemistry
- Graduate School of Science and Engineering
- University of Toyama
- Toyama 930-8555
- Japan
| | - Shen Ye
- Institute for Catalysis
- Hokkaido University
- Kita-ku
- Japan
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
| | - Akihiro Morita
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Aoba-ku
- Japan
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30
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Mixed DPPC/POPC Monolayers: All-atom Molecular Dynamics Simulations and Langmuir Monolayer Experiments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:3120-3130. [DOI: 10.1016/j.bbamem.2016.09.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/10/2016] [Accepted: 09/19/2016] [Indexed: 11/18/2022]
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31
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Estillore AD, Trueblood JV, Grassian VH. Atmospheric chemistry of bioaerosols: heterogeneous and multiphase reactions with atmospheric oxidants and other trace gases. Chem Sci 2016; 7:6604-6616. [PMID: 28567251 PMCID: PMC5450524 DOI: 10.1039/c6sc02353c] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/17/2016] [Indexed: 12/20/2022] Open
Abstract
Once airborne, biologically-derived aerosol particles are prone to reaction with various atmospheric oxidants such as OH, NO3, and O3.
Advances in analytical techniques and instrumentation have now established methods for detecting, quantifying, and identifying the chemical and microbial constituents of particulate matter in the atmosphere. For example, recent cryo-TEM studies of sea spray have identified whole bacteria and viruses ejected from ocean seawater into air. A focal point of this perspective is directed towards the reactivity of aerosol particles of biological origin with oxidants (OH, NO3, and O3) present in the atmosphere. Complementary information on the reactivity of aerosol particles is obtained from field investigations and laboratory studies. Laboratory studies of different types of biologically-derived particles offer important information related to their impacts on the local and global environment. These studies can also unravel a range of different chemistries and reactivity afforded by the complexity and diversity of the chemical make-up of these particles. Laboratory experiments as the ones reviewed herein can elucidate the chemistry of biological aerosols.
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Affiliation(s)
- Armando D Estillore
- Department of Chemistry & Biochemistry , University of California San Diego , La Jolla , California 92093 , USA . ; ; Tel: +1-858-534-2499
| | - Jonathan V Trueblood
- Department of Chemistry & Biochemistry , University of California San Diego , La Jolla , California 92093 , USA . ; ; Tel: +1-858-534-2499
| | - Vicki H Grassian
- Department of Chemistry & Biochemistry , University of California San Diego , La Jolla , California 92093 , USA . ; ; Tel: +1-858-534-2499.,Scripps Institution of Oceanography and Department of Nanoengineering , University of California San Diego , La Jolla , California 92093 , USA
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32
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Li B, Li X, Ma YH, Han X, Wu FG, Guo Z, Chen Z, Lu X. Sum Frequency Generation of Interfacial Lipid Monolayers Shows Polarization Dependence on Experimental Geometries. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:7086-7095. [PMID: 27364607 DOI: 10.1021/acs.langmuir.6b01944] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy has been widely employed to investigate molecular structures of biological surfaces and interfaces including model cell membranes. A variety of lipid monolayers or bilayers serving as model cell membranes and their interactions with many different molecules have been extensively studied using SFG. Here, we conducted an in-depth investigation on polarization-dependent SFG signals collected from interfacial lipid monolayers using different experimental geometries, i.e., the prism geometry (total internal reflection) and the window geometry (external reflection). The different SFG spectral features of interfacial lipid monolayers detected using different experimental geometries are due to the interplay between the varied Fresnel coefficients and second-order nonlinear susceptibility tensor terms of different vibrational modes (i.e., ss and as modes of methyl groups), which were analyzed in detail in this study. Therefore, understanding the interplay between the interfacial Fresnel coefficients and χ((2)) tensors is a prerequisite for correctly understanding the SFG spectral features with respect to different experimental geometries. More importantly, the derived information in this paper should not be limited to the methyl groups with a C3v symmetry; valid extension to interfacial functional groups with different molecular symmetries and even chiral interfaces could be expected.
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Affiliation(s)
- Bolin Li
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Xu Li
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Yong-Hao Ma
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Xiaofeng Han
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Fu-Gen Wu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
| | - Zhirui Guo
- Department of Geriatrics, Second Affiliated Hospital of Nanjing Medical University , Nanjing 210029, P. R. China
| | - Zhan Chen
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, China
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33
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Wu HL, Tong Y, Peng Q, Li N, Ye S. Phase transition behaviors of the supported DPPC bilayer investigated by sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM). Phys Chem Chem Phys 2016; 18:1411-21. [DOI: 10.1039/c5cp04960a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The phase transition behaviors of a supported bilayer of dipalmitoylphosphatidyl-choline (DPPC) have been systematically evaluated by in situ sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM).
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Affiliation(s)
- Heng-Liang Wu
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Yujin Tong
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Qiling Peng
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Na Li
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
| | - Shen Ye
- Catalysis Research Center
- Hokkaido University
- Sapporo 001-0021
- Japan
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34
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Fu L, Wang Z, Batista VS, Yan ECY. New Insights from Sum Frequency Generation Vibrational Spectroscopy into the Interactions of Islet Amyloid Polypeptides with Lipid Membranes. J Diabetes Res 2015; 2016:7293063. [PMID: 26697504 PMCID: PMC4677203 DOI: 10.1155/2016/7293063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/24/2015] [Indexed: 11/17/2022] Open
Abstract
Studies of amyloid polypeptides on membrane surfaces have gained increasing attention in recent years. Several studies have revealed that membranes can catalyze protein aggregation and that the early products of amyloid aggregation can disrupt membrane integrity, increasing water permeability and inducing ion cytotoxicity. Nonetheless, probing aggregation of amyloid proteins on membrane surfaces is challenging. Surface-specific methods are required to discriminate contributions of aggregates at the membrane interface from those in the bulk phase and to characterize protein secondary structures in situ and in real time without the use of perturbing spectroscopic labels. Here, we review the most recent applications of sum frequency generation (SFG) vibrational spectroscopy applied in conjunction with computational modeling techniques, a joint experimental and computational methodology that has provided valuable insights into the aggregation of islet amyloid polypeptide (IAPP) on membrane surfaces. These applications show that SFG can provide detailed information about structures, kinetics, and orientation of IAPP during interfacial aggregation, relevant to the molecular mechanisms of type II diabetes. These recent advances demonstrate the promise of SFG as a new approach for studying amyloid diseases at the molecular level and for the rational drug design targeting early aggregation products on membrane surfaces.
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Affiliation(s)
- Li Fu
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352, USA
| | - Zhuguang Wang
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520, USA
| | - Victor S. Batista
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520, USA
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520, USA
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35
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Qiao L, Ge A, Liang Y, Ye S. Oxidative Degradation of the Monolayer of 1-Palmitoyl-2-Oleoyl-sn-Glycero-3-Phosphocholine (POPC) in Low-Level Ozone. J Phys Chem B 2015; 119:14188-99. [DOI: 10.1021/acs.jpcb.5b08985] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lin Qiao
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | - Aimin Ge
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | - Yimin Liang
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
| | - Shen Ye
- Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan
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36
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Bhamla MS, Nash WL, Elliott S, Fuller GG. Influence of lipid coatings on surface wettability characteristics of silicone hydrogels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3820-3828. [PMID: 25280206 DOI: 10.1021/la503437a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Insoluble lipids serve vital functions in our bodies and interact with biomedical devices, e.g., the tear film on a contact lens. Over a period of time, these naturally occurring lipids form interfacial coatings that modify the wettability characteristics of these foreign synthetic surfaces. In this study, we examine the deposition and consequences of tear film lipids on silicone hydrogel (SiHy) contact lenses. We use bovine meibum, which is a complex mixture of waxy esters, cholesterol esters, and lipids that is secreted from the meibomian glands located on the upper and lower eyelids of mammals. For comparison, we study two commercially available model materials: dipalmitoylphosphatidylcholine (DPPC) and cholesterol. Upon deposition, we find that DPPC and meibum remain closer to the SiHy surface than cholesterol, which diffuses further into the porous SiHy matrix. In addition, we also monitor the fate of unstable thin liquid films that consequently rupture and dewet on these lipid-decorated surfaces. This dewetting provides valuable qualitative and quantitative information about the wetting characteristics of these SiHy substrates. We observe that decorating the SiHy surface with simple model lipids such as DPPC and cholesterol increases the hydrophilicity, which consequently inhibits dewetting, whereas meibum behaves conversely.
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Affiliation(s)
- M Saad Bhamla
- †Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Walter L Nash
- ‡Alcon Research Ltd., Fort Worth, Texas 76134, United States
| | - Stacey Elliott
- ‡Alcon Research Ltd., Fort Worth, Texas 76134, United States
| | - Gerald G Fuller
- †Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
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37
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Wu FG, Sun HY, Zhou Y, Deng G, Yu ZW. Molecular-level pictures of the phase transitions of saturated and unsaturated phospholipid binary mixtures. RSC Adv 2015. [DOI: 10.1039/c4ra07569b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Saturated and unsaturated lipids change nonsynchronously upon heating-induced phase transitions.
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Affiliation(s)
- Fu-Gen Wu
- Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education)
- Department of Chemistry
- Tsinghua University
- Beijing 100084
- P. R. China
| | - Hai-Yuan Sun
- Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education)
- Department of Chemistry
- Tsinghua University
- Beijing 100084
- P. R. China
| | - Yu Zhou
- Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education)
- Department of Chemistry
- Tsinghua University
- Beijing 100084
- P. R. China
| | - Geng Deng
- Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education)
- Department of Chemistry
- Tsinghua University
- Beijing 100084
- P. R. China
| | - Zhi-Wu Yu
- Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of Education)
- Department of Chemistry
- Tsinghua University
- Beijing 100084
- P. R. China
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38
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Ye S, Tong Y, Ge A, Qiao L, Davies PB. Interfacial Structure of Soft Matter Probed by SFG Spectroscopy. CHEM REC 2014; 14:791-805. [DOI: 10.1002/tcr.201402039] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Indexed: 01/05/2023]
Affiliation(s)
- Shen Ye
- Catalysis Research Center; Hokkaido University; Sapporo 001-0021 Japan
| | - Yujin Tong
- Catalysis Research Center; Hokkaido University; Sapporo 001-0021 Japan
| | - Aimin Ge
- Catalysis Research Center; Hokkaido University; Sapporo 001-0021 Japan
| | - Lin Qiao
- Catalysis Research Center; Hokkaido University; Sapporo 001-0021 Japan
| | - Paul B. Davies
- Department of Chemistry; Cambridge University; Cambridge CB2 1EW UK
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