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Orlikowska-Rzeznik H, Versluis J, Bakker HJ, Piatkowski L. Cholesterol Changes Interfacial Water Alignment in Model Cell Membranes. J Am Chem Soc 2024; 146:13151-13162. [PMID: 38687869 PMCID: PMC11099968 DOI: 10.1021/jacs.4c00474] [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: 01/11/2024] [Revised: 04/20/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
The nanoscopic layer of water that directly hydrates biological membranes plays a critical role in maintaining the cell structure, regulating biochemical processes, and managing intermolecular interactions at the membrane interface. Therefore, comprehending the membrane structure, including its hydration, is essential for understanding the chemistry of life. While cholesterol is a fundamental lipid molecule in mammalian cells, influencing both the structure and dynamics of cell membranes, its impact on the structure of interfacial water has remained unknown. We used surface-specific vibrational sum-frequency generation spectroscopy to study the effect of cholesterol on the structure and hydration of monolayers of the lipids 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and egg sphingomyelin (SM). We found that for the unsaturated lipid DOPC, cholesterol intercalates in the membrane without significantly changing the orientation of the lipid tails and the orientation of the water molecules hydrating the headgroups of DOPC. In contrast, for the saturated lipids DPPC and SM, the addition of cholesterol leads to clearly enhanced packing and ordering of the hydrophobic tails. It is also observed that the orientation of the water hydrating the lipid headgroups is enhanced upon the addition of cholesterol. These results are important because the orientation of interfacial water molecules influences the cell membranes' dipole potential and the strength and specificity of interactions between cell membranes and peripheral proteins and other biomolecules. The lipid nature-dependent role of cholesterol in altering the arrangement of interfacial water molecules offers a fresh perspective on domain-selective cellular processes, such as protein binding.
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Affiliation(s)
- Hanna Orlikowska-Rzeznik
- Faculty
of Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
| | - Jan Versluis
- AMOLF,
Ultrafast Spectroscopy, 1098 XG Amsterdam, The Netherlands
| | - Huib J. Bakker
- AMOLF,
Ultrafast Spectroscopy, 1098 XG Amsterdam, The Netherlands
| | - Lukasz Piatkowski
- Faculty
of Materials Engineering and Technical Physics, Poznan University of Technology, 60-965 Poznan, Poland
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2
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Yu C, Shang P, Guo Y, Zhang Z. In Situ Heterodyne-Detected Second-Harmonic Generation Study of the Influence of Cholesterol on Dye Molecule Adsorption on Lipid Membrane. J Phys Chem B 2024; 128:1892-1899. [PMID: 38354410 DOI: 10.1021/acs.jpcb.3c07130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Cholesterol plays an essential role in regulating the functionality of biomembranes. This study employed in situ second-harmonic generation (SHG) to investigate the adsorption behavior of the dye molecule 4-(4-(diethylamino)styryl)-N-methyl-pyridinium iodide (D289) on a biomimic membrane composed of 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DPPG) and cholesterol. The time-dependent polarization SHG intensity exhibited an initial rapid increase, followed by a subsequent decline. The initial increased SHG intensity is responsible for the electrostatic interaction-driven adsorption of D289 onto the membrane, while the decrease in the SHG signal results from the broadening of the orientation distribution within the membrane. Heterodyne-detected SHG (HD-SHG) measurements demonstrated that the adsorption of dye molecules influenced the phase of the induced electric field. The interfacial potential Φ(0) as a function of time was measured, and we found that even after reaching a stable Stern layer state, the diffusion layer continued to exhibit a dynamic change. This study offers a comprehensive understanding of the influence of cholesterol on adsorption, reorientation dynamics, and dynamic changes in the reorientation of water in the diffusion layer.
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Affiliation(s)
- Changhui Yu
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy Sciences, Beijing 100049, China
| | - Peng Shang
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy Sciences, Beijing 100049, China
| | - Yuan Guo
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy Sciences, Beijing 100049, China
| | - Zhen Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy Sciences, Beijing 100049, China
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3
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Raghavendra, Kumar B, Chari SN. Effect of γ-Oryzanol on the LE-LC Phase Coexistence Region of DPPC Langmuir Monolayer. J Membr Biol 2023; 256:413-422. [PMID: 37269365 DOI: 10.1007/s00232-023-00288-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/06/2023] [Indexed: 06/05/2023]
Abstract
We have studied the effect of relative composition of γ-Oryzanol (γ-Or) on the liquid expanded-liquid condensed phase coexistence region in the mixed Langmuir monolayer of γ-Or and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) molecules at air-water interface. The surface manometry studies at a fixed temperature show that the mixture of γ-Or and DPPC forms a stable monolayer at air-water interface. As the relative composition of γ-Or increases the range of area per molecule over which the coexistence of liquid expanded (LE)-liquid condensed (LC) phases exists reduces. Although the LE-LC phase coexistence corresponds to the first-order phase transition, the slope of the surface pressure-area per molecule isotherm is non-zero. Earlier studies have attributed the non-zero slope in LE-LC phase coexistence region to the influence of the strain between the ordered LC phase and disordered LE phase. The effect of strain on the coexistence of LE-LC phases can be studied in terms of molecular density-strain coupling. Our analysis of the liquid condensed-liquid expanded coexistence region in the isotherms of mixed monolayers of DPPC and γ-Or shows that with the increase in the mole fraction of sterol in the mixed monolayer the molecular lateral density-strain coupling increases. However, at 0.6 mole fraction of γ-Or in the mixed monolayer the coupling decreases. This is corroborated by the observation of minimum Gibb's free energy of the mixed monolayer at this relative composition of γ-Or indicating better packing of molecules.
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Affiliation(s)
- Raghavendra
- Department of Physics, Central University of Karnataka, Aland Road, Kadaganchi, Kalaburagi, Karnataka, 585102, India
| | - Bharat Kumar
- Department of Physics, Central University of Karnataka, Aland Road, Kadaganchi, Kalaburagi, Karnataka, 585102, India.
| | - Siva N Chari
- Department of Physics, Central University of Karnataka, Aland Road, Kadaganchi, Kalaburagi, Karnataka, 585102, India
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4
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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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5
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Li Y, Feng R, Liu M, Guo Y, Zhang Z. Mechanism by Which Cholesterol Induces Sphingomyelin Conformational Changes at an Air/Water Interface. J Phys Chem B 2022; 126:5481-5489. [PMID: 35839485 DOI: 10.1021/acs.jpcb.2c03127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work investigates the interactions in cholesterol and sphingomyelin monolayers at the molecular level by high-resolution broadband sum frequency generation vibrational spectroscopy (HR-BB-SFG-VS). The SFG spectra of natural egg sphingomyelin (ESM) as a function of cholesterol concentration are obtained at an air/water interface under different polarization combinations. The analysis of the spectra shows that cholesterol can induce sphingomyelin conformational changes at an air/water interface. The mechanism is proposed. When cholesterol is inserted into the ESM monolayer, the inherent intramolecular hydrogen bonds between the phosphate moiety and 3OH in the sphingosine backbones are destroyed. During this process, the sphingosine backbones become more ordered, while the conformation of the N-linked long acid chain remains unaltered. The OH of the cholesterol head group can bind to the -PO-2 of the ESM molecule, and the orientation of the -PO-2 in the head groups changes to be more parallel to the interface.
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Affiliation(s)
- Yiyi Li
- Beijing National Laboratory for Molecular Sciences, Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rongjuan Feng
- Beijing National Laboratory for Molecular Sciences, Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Minghua Liu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Guo
- Beijing National Laboratory for Molecular Sciences, Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Zhang
- Beijing National Laboratory for Molecular Sciences, Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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6
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Ruiz GCM, Pazin WM, do Carmo Morato LF, Oliveira ON, Constantino CJL. Correlating mono- and bilayers of lipids to investigate the pronounced effects of steroid hormone 17α-ethynylestradiol on membrane models of DPPC/cholesterol. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Jaroque GN, Sartorelli P, Caseli L. The effect of the monocyclic monoterpene tertiary alcohol γ-terpineol on biointerfaces containing cholesterol. Chem Phys Lipids 2020; 230:104915. [DOI: 10.1016/j.chemphyslip.2020.104915] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/19/2020] [Accepted: 04/19/2020] [Indexed: 01/16/2023]
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8
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Possarle LHRR, Siqueira Junior JR, Caseli L. Insertion of carbon nanotubes in Langmuir-Blodgett films of stearic acid and asparaginase enhancing the catalytic performance. Colloids Surf B Biointerfaces 2020; 192:111032. [PMID: 32330820 DOI: 10.1016/j.colsurfb.2020.111032] [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: 12/20/2019] [Revised: 03/05/2020] [Accepted: 04/09/2020] [Indexed: 11/22/2022]
Abstract
In this paper, carbon nanotubes (CNT) were adsorbed on stearic acid (SA) Langmuir monolayers to serve as matrices for the incorporation of asparaginase. The interaction between the components at the air-water interface was evaluated by surface pressure-area isotherms, surface potential-area isotherms, polarization-modulation reflection absorption infrared spectroscopy (PM-IRRAS), and Brewster angle microscopy (BAM). The enzyme expanded the monolayers and changed the thermodynamic and electrical properties of the SA-CNT monolayers, as detected with the isotherms. PM-IRRAS spectra showed that the enzyme keeps its secondary structure when adsorbed at the monolayers and also alters the morphology of the air-water interface, as identified with BAM. The hybrid floating films were transferred to solid supports through the Langmuir-Blodgett (LB) technique, and the cotransfer of the enzyme was confirmed with fluorescence spectroscopy. The catalytic activity of asparaginase in the LB films was studied with UV-vis spectroscopy, which showed that the presence of CNT in the enzyme-lipid LB film not only tuned the catalytic activity, but also helped conserve its enzyme activity after weeks, showing higher persisting values of activity. UV-vis spectroscopy also showed that the catalytic activity is dependent basically on the enzyme molecules present on the surface of the LB films since multilayer films did not provide a proportional increase of enzyme activity. These results are related to the synergism between the compounds on the active layer, leading to a molecular architecture that allowed the adequate molecular accommodation of the analyte with the catalytic sites of the enzyme, which also preserved the asparaginase activity. This work then demonstrates the feasibility of employing LB films composed of fatty acids, CNT, and enzymes as devices for biosensing applications.
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Affiliation(s)
| | - José Roberto Siqueira Junior
- Institute of Exact Sciences, Natural and Education, Federal University of Triângulo Mineiro (UFTM), 38064-200 Uberaba, MG, Brazil
| | - Luciano Caseli
- Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo (UNIFESP), 09913-030 Diadema, SP, Brazil.
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9
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Effect of Escherichia coli on phospholipid monolayers: surface tensiometry and Brewster angle microscopy measurements. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2019; 49:71-84. [PMID: 31863194 DOI: 10.1007/s00249-019-01413-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/07/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022]
Abstract
The effect of Escherichia coli (E. coli) cells on two phospholipids [dipalmitoyl phosphatidylcholine (DPPC) and dimyristoyl phosphatidylcholine (DMPC)] monolayers at the surface of a 1.5 wt% NaCl salt solution has been investigated using surface tension measurement and Brewster angle microscopy. The results showed that a DPPC monolayer that has an elastic structure was changed in morphology by interaction with E. coli cells, whereas a DMPC monolayer that has an expandable structure did not change in morphology. In particular, the morphology changed significantly around the liquid-expanded (LE)-liquid-condensed (LC) phase transition point for the DPPC monolayer. It was found that the LE-LC phase transition range in a DPPC monolayer was sensitive to influence from the outside of the monolayer such as the action of E. coli cells. Such a monolayer has the potential for application as a membrane sensor for detecting a small amount of bacteria in a short time.
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10
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Link KA, Spurzem GN, Tuladhar A, Chase Z, Wang Z, Wang H, Walker RA. Cooperative Adsorption of Trehalose to DPPC Monolayers at the Water–Air Interface Studied with Vibrational Sum Frequency Generation. J Phys Chem B 2019; 123:8931-8938. [DOI: 10.1021/acs.jpcb.9b07770] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Aashish Tuladhar
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Zizwe Chase
- Department of Physics and Astronomy, Howard University, Washington, D.C. 20059, United States
| | - Zheming Wang
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Hongfei Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China
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11
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Toledo-Fuentes X, Molinaro C, Cecchet F. Interfacial charges drive the organization of supported lipid membranes and their interaction with nanoparticles. Colloids Surf B Biointerfaces 2018; 172:254-261. [DOI: 10.1016/j.colsurfb.2018.08.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 08/10/2018] [Accepted: 08/11/2018] [Indexed: 12/27/2022]
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12
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Li Y, Feng R, Lin L, Liu M, Guo Y, Zhang Z. Ordering effects of cholesterol on sphingomyelin monolayers investigated by high-resolution broadband sum-frequency generation vibrational spectroscopy. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2017.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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13
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Cruz Gomes da Silva RL, Oliveira da Silva HF, da Silva Gasparotto LH, Caseli L. How the interaction of PVP-stabilized Ag nanoparticles with models of cellular membranes at the air-water interface is modulated by the monolayer composition. J Colloid Interface Sci 2018; 512:792-800. [DOI: 10.1016/j.jcis.2017.10.091] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 12/19/2022]
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14
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Feng RJ, Li X, Zhang Z, Lu Z, Guo Y. Spectral assignment and orientational analysis in a vibrational sum frequency generation study of DPPC monolayers at the air/water interface. J Chem Phys 2016; 145:244707. [DOI: 10.1063/1.4972564] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Rong-Juan Feng
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xia Li
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Zhang
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhou Lu
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuan Guo
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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15
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Yu T, Zhou G, Hu X, Ye S. Transport and Organization of Cholesterol in a Planar Solid-Supported Lipid Bilayer Depend on the Phospholipid Flip-Flop Rate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11681-11689. [PMID: 27756133 DOI: 10.1021/acs.langmuir.6b02560] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Understanding the transport behavior of the cholesterol molecules within a cell membrane is a key challenge in cell biology at present. Here, we have applied sum frequency generation vibrational spectroscopy to characterize the transport and organization of cholesterol in different kinds of planar solid-supported lipid bilayers by combining achiral- and chiral-sensitive polarization measurements. This method allows us to distinguish the organization of cholesterol in tail-to-tail, head-to-tail, head-to-head, and side-by-side manners. It is found that the movement of cholesterol in the lipid bilayer largely depends on the flip-flop rate of the phospholipid. The flip-flop dynamics of the phospholipid and cholesterol are synchronous. In the solid-supported zwitterionic phosphocholine lipid bilayer, the cholesterol molecules flip quickly from the distal leaflet to the neutral proximal leaflet of the bilayer and form tail-to-tail organization on both leaflets. The phosphocholine lipid and cholesterol show the same flip-flop rate. However, when the proximal leaflet is prepared using negative glycerol phospholipids, cholesterol organizes itself by mainly forming an α-β structure on the distal leaflet. Because of the strong interaction between the glycerol phospholipid and the substrate, no or only partial cholesterol molecules flip from the distal leaflet to the negatively charged proximal leaflet. However, the cholesterol molecules undergo flip-flop in the presence of salt solution because the ions weaken the interaction between the negative phospholipid and the substrate.
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Affiliation(s)
- Ting Yu
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Guangnan Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Xia Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Shuji Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
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16
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Fioravanti V, Brandhoff L, van den Driesche S, Breiteneder H, Kitzwögerer M, Hafner C, Vellekoop MJ. An Infrared Absorbance Sensor for the Detection of Melanoma in Skin Biopsies. SENSORS 2016; 16:s16101659. [PMID: 27735858 PMCID: PMC5087447 DOI: 10.3390/s16101659] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 09/24/2016] [Accepted: 09/28/2016] [Indexed: 11/16/2022]
Abstract
An infrared (IR) absorbance sensor has been designed, realized and tested with the aim of detecting malignant melanomas in human skin biopsies. The sensor has been designed to obtain fast measurements (80 s) of a biopsy using a small light spot (0.5 mm in diameter, typically five to 10 times smaller than the biopsy size) to investigate different biopsy areas. The sensor has been equipped with a monochromator to record the whole IR spectrum in the 3330-3570 nm wavelength range (where methylene and methyl stretching vibrations occur) for a qualitative spectral investigation. From the collected spectra, the CH₂ stretch ratio values (ratio of the absorption intensities of the symmetric to asymmetric CH₂ stretching peaks) are determined and studied as a cancer indicator. Melanoma areas exhibit different spectral shapes and significantly higher CH₂ stretch ratios when compared to healthy skin. The results of the infrared investigation are compared with standard histology. This study shows that the IR sensor is a promising supportive tool to improve the diagnosis of melanoma during histopathological analysis, decreasing the risk of misdiagnosis.
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Affiliation(s)
- Valeria Fioravanti
- Institute for Microsensors, Actuators and Systems (IMSAS), MCB, University of Bremen, Bremen D-28359, Germany.
| | - Lukas Brandhoff
- Institute for Microsensors, Actuators and Systems (IMSAS), MCB, University of Bremen, Bremen D-28359, Germany.
| | - Sander van den Driesche
- Institute for Microsensors, Actuators and Systems (IMSAS), MCB, University of Bremen, Bremen D-28359, Germany.
| | - Heimo Breiteneder
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna A-1090, Austria.
| | - Melitta Kitzwögerer
- Department of Pathology, University Hospital St. Poelten, Karl Landsteiner University of Health Sciences, St. Poelten A-3100, Austria.
| | - Christine Hafner
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna A-1090, Austria.
- Department of Dermatology, University Hospital St. Poelten, Karl Landsteiner University of Health Sciences, St. Poelten A-3100, Austria.
| | - Michael J Vellekoop
- Institute for Microsensors, Actuators and Systems (IMSAS), MCB, University of Bremen, Bremen D-28359, Germany.
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17
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Allhusen JS, Kimball DR, Conboy JC. Structural Origins of Cholesterol Accelerated Lipid Flip-Flop Studied by Sum-Frequency Vibrational Spectroscopy. J Phys Chem B 2016; 120:3157-68. [PMID: 26978577 DOI: 10.1021/acs.jpcb.6b01254] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The unique structure of cholesterol and its role in modulating lipid translocation (flip-flop) were examined using sum-frequency vibrational spectroscopy (SFVS). Two structural analogues of cholesterol--cholestanol and cholestene--were examined to explore the influence of ring rigidity and amphiphilicity on controlling distearoylphosphocholine (DSPC) flip-flop. Kinetic rates for DSPC flip-flop were determined as a function of sterol concentration and temperature. All three sterols increased the rate of DSPC flip-flop in a concentration-dependent manner following the order cholestene > cholestanol > cholesterol. Rates of DSPC flip-flop were used to calculate the thermodynamic activation free energy barrier (ΔG(‡)) in the presence of cholesterol, cholestanol, and cholestene. The acyl chain gauche content of DSPC, mean lipid area, and membrane compressibility were correlated to observed trends in ΔG(‡). ΔG(‡) for DSPC flip-flop showed a strong positive correlation with the molar compression modulus (K*) of the membrane, influenced by the type and concentration of the sterol added. Interestingly, cholesterol is distinctive in maintaining invariant membrane compressibility over the range of 2-10 mol %. The results in this study demonstrate that the compression modulus of a membrane plays a significant role in moderating ΔG(‡) and the kinetics of native, protein-free, lipid translocation in membranes.
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Affiliation(s)
- John S Allhusen
- Department of Chemistry, University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Dylan R Kimball
- Department of Chemistry, University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - John C Conboy
- Department of Chemistry, University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112, United States
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18
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Wiącek AE, Adryańczyk E. Interfacial Properties of Phosphatidylcholine-based Dispersed Systems. Ind Eng Chem Res 2015. [DOI: 10.1021/acs.iecr.5b01429] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Agnieszka Ewa Wiącek
- Department of Interfacial
Phenomena, Faculty of Chemistry, Maria Curie-Skłodowska University, 20031 Lublin, Poland
| | - Emilian Adryańczyk
- Department of Interfacial
Phenomena, Faculty of Chemistry, Maria Curie-Skłodowska University, 20031 Lublin, Poland
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19
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Kuo AT, Chang CH. Elucidating the Effects of Cholesterol on the Molecular Packing of Double-chained Cationic Lipid Langmuir Monolayers by Infrared Reflection-absorption Spectroscopy. J Oleo Sci 2015; 64:455-65. [DOI: 10.5650/jos.ess14266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- An-Tsung Kuo
- Department of Chemical Engineering, National Cheng Kung University
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20
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Advanced experimental methods toward understanding biophysicochemical interactions of interfacial biomolecules by using sum frequency generation vibrational spectroscopy. Sci China Chem 2014. [DOI: 10.1007/s11426-014-5233-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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21
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Velarde L, Wang HF. Unified treatment and measurement of the spectral resolution and temporal effects in frequency-resolved sum-frequency generation vibrational spectroscopy (SFG-VS). Phys Chem Chem Phys 2014; 15:19970-84. [PMID: 24076622 DOI: 10.1039/c3cp52577e] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The lack of understanding of the temporal effects and the restricted ability to control experimental conditions in order to obtain intrinsic spectral lineshapes in surface sum-frequency generation vibrational spectroscopy (SFG-VS) have limited its applications in surface and interfacial studies. The emergence of high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS) with sub-wavenumber resolution [Velarde et al., J. Chem. Phys., 2011, 135, 241102] offers new opportunities for obtaining and understanding the spectral lineshapes and temporal effects in SFG-VS. Particularly, the high accuracy of the HR-BB-SFG-VS experimental lineshape provides detailed information on the complex coherent vibrational dynamics through direct spectral measurements. Here we present a unified formalism for the theoretical and experimental routes for obtaining an accurate lineshape of the SFG response. Then, we present a detailed analysis of a cholesterol monolayer at the air/water interface with higher and lower resolution SFG spectra along with their temporal response. With higher spectral resolution and accurate vibrational spectral lineshapes, it is shown that the parameters of the experimental SFG spectra can be used both to understand and to quantitatively reproduce the temporal effects in lower resolution SFG measurements. This perspective provides not only a unified picture but also a novel experimental approach to measuring and understanding the frequency-domain and time-domain SFG response of a complex molecular interface.
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Affiliation(s)
- Luis Velarde
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352, USA.
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22
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Volpati D, Aoki PHB, Alessio P, Pavinatto FJ, Miranda PB, Constantino CJL, Oliveira ON. Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces. Adv Colloid Interface Sci 2014; 207:199-215. [PMID: 24530000 DOI: 10.1016/j.cis.2014.01.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/28/2013] [Accepted: 01/13/2014] [Indexed: 01/26/2023]
Abstract
Investigation into nanostructured organic films has served many purposes, including the design of functionalized surfaces that may be applied in biomedical devices and tissue engineering and for studying physiological processes depending on the interaction with cell membranes. Of particular relevance are Langmuir monolayers, Langmuir-Blodgett (LB) and layer-by-layer (LbL) films used to simulate biological interfaces. In this review, we shall focus on the use of vibrational spectroscopy methods to probe molecular-level interactions at biomimetic interfaces, with special emphasis on three surface-specific techniques, namely sum frequency generation (SFG), polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) and surface-enhanced Raman scattering (SERS). The two types of systems selected for exemplifying the potential of the methods are the cell membrane models and the functionalized surfaces with biomolecules. Examples will be given on how SFG and PM-IRRAS can be combined to determine the effects from biomolecules on cell membrane models, which include determination of the orientation and preservation of secondary structure. Crucial information for the action of biomolecules on model membranes has also been obtained with PM-IRRAS, as is the case of chitosan removing proteins from the membrane. SERS will be shown as promising for enabling detection limits down to the single-molecule level. The strengths and limitations of these methods will also be discussed, in addition to the prospects for the near future.
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Affiliation(s)
- Diogo Volpati
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | - Pedro H B Aoki
- Faculty of Science and Technology, UNESP, Presidente Prudente, CEP 19060-900 SP,Brazil
| | - Priscila Alessio
- Faculty of Science and Technology, UNESP, Presidente Prudente, CEP 19060-900 SP,Brazil
| | - Felippe J Pavinatto
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | - Paulo B Miranda
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | | | - Osvaldo N Oliveira
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil.
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23
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Ma S, Li H, Tian K, Ye S, Luo Y. In Situ and Real-Time SFG Measurements Revealing Organization and Transport of Cholesterol Analogue 6-Ketocholestanol in a Cell Membrane. J Phys Chem Lett 2014; 5:419-424. [PMID: 26276585 DOI: 10.1021/jz402537w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Cholesterol organization and transport within a cell membrane are essential for human health and many cellular functions yet remain elusive so far. Using cholesterol analogue 6-ketocholestanol (6-KC) as a model, we have successfully exploited sum frequency generation vibrational spectroscopy (SFG-VS) to track the organization and transport of cholesterol in a membrane by combining achiral-sensitive ssp (ppp) and chiral-sensitive psp polarization measurements. It is found that 6-KC molecules are aligned at the outer leaflet of the DMPC lipid bilayer with a tilt angle of about 10°. 6-KC organizes itself by forming an α-β structure at low 6-KC concentration and most likely a β-β structure at high 6-KC concentration. Among all proposed models, our results favor the so-called umbrella model with formation of a 6-KC cluster. Moreover, we have found that the long anticipated flip-flop motion of 6-KC in the membrane takes time to occur, at least much longer than previously thought. All of these interesting findings indicate that it is critical to explore in situ, real-time, and label-free methodologies to obtain a precise molecular description of cholesterol's behavior in membranes. This study represents the first application of SFG to reveal the cholesterol-lipid interaction mechanism at the molecular level.
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Affiliation(s)
| | | | | | | | - Yi Luo
- ⊥Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, S-10961 Stockholm, Sweden
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24
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Kett PJN, Casford MTL, Davies PB. Orientation of cholesterol in hybrid bilayer membranes calculated from the phases of methyl resonances in sum frequency generation spectra. J Chem Phys 2013; 138:225101. [DOI: 10.1063/1.4807854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- P J N Kett
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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25
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Kett PJN, Casford MTL, Davies PB. Sum Frequency Generation Vibrational Spectroscopy of Cholesterol in Hybrid Bilayer Membranes. J Phys Chem B 2013; 117:6455-65. [DOI: 10.1021/jp403584j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Peter J. N. Kett
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Michael T. L. Casford
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Paul B. Davies
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
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26
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Prudovsky I, Kumar TKS, Sterling S, Neivandt D. Protein-phospholipid interactions in nonclassical protein secretion: problem and methods of study. Int J Mol Sci 2013; 14:3734-72. [PMID: 23396106 PMCID: PMC3588068 DOI: 10.3390/ijms14023734] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/24/2013] [Accepted: 01/25/2013] [Indexed: 12/30/2022] Open
Abstract
Extracellular proteins devoid of signal peptides use nonclassical secretion mechanisms for their export. These mechanisms are independent of the endoplasmic reticulum and Golgi. Some nonclassically released proteins, particularly fibroblast growth factors (FGF) 1 and 2, are exported as a result of their direct translocation through the cell membrane. This process requires specific interactions of released proteins with membrane phospholipids. In this review written by a cell biologist, a structural biologist and two membrane engineers, we discuss the following subjects: (i) Phenomenon of nonclassical protein release and its biological significance; (ii) Composition of the FGF1 multiprotein release complex (MRC); (iii) The relationship between FGF1 export and acidic phospholipid externalization; (iv) Interactions of FGF1 MRC components with acidic phospholipids; (v) Methods to study the transmembrane translocation of proteins; (vi) Membrane models to study nonclassical protein release.
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Affiliation(s)
- Igor Prudovsky
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME 04074, USA
| | | | - Sarah Sterling
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
| | - David Neivandt
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
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27
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Weeraman C, Chen M, Moffatt DJ, Lausten R, Stolow A, Johnston LJ. A combined vibrational sum frequency generation spectroscopy and atomic force microscopy study of sphingomyelin-cholesterol monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:12999-13007. [PMID: 22889131 DOI: 10.1021/la301332e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A combination of vibrational sum frequency generation spectroscopy and atomic force microscopy is used to study the changes in morphology and conformational order in monolayers prepared from three natural sphingomyelin (SM) mixtures as a function of surface pressure and cholesterol concentration. The most homogeneous SM gave monolayers with well-ordered acyl chains and few gauche defects with relatively small effects of either increasing surface pressure or cholesterol addition. Heterogeneous SM mixtures with a mixture of acyl chain lengths or with significant fractions of unsaturated acyl chains had much larger contributions from gauche defects at low surface pressure and gave increasingly well-ordered monolayers as the surface pressure increased. They also showed substantial increases in lipid chain order after cholesterol addition. Overall, these results are consistent with the strong hydrogen bonding capacity of SM leading to well-ordered monolayers over a range of surface pressures. The changes in acyl chain order for natural SMs as a function of cholesterol are relevant to formation of sphingolipid-cholesterol enriched domains in cell membranes.
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Affiliation(s)
- Champika Weeraman
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, ON, Canada
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28
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Peng X, Hofmann AM, Reuter S, Frey H, Kressler J. Mixed layers of DPPC and a linear poly(ethylene glycol)-b-hyperbranched poly(glycerol) block copolymer having a cholesteryl end group. Colloid Polym Sci 2012. [DOI: 10.1007/s00396-012-2613-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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29
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Szcześ A, Jurak M, Chibowski E. Stability of binary model membranes--prediction of the liposome stability by the Langmuir monolayer study. J Colloid Interface Sci 2012; 372:212-6. [PMID: 22326232 DOI: 10.1016/j.jcis.2012.01.035] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 01/18/2012] [Accepted: 01/20/2012] [Indexed: 11/29/2022]
Abstract
In this paper, usefulness of the Langmuir monolayer study is demonstrated for predictions of the stability of liposomes composed of dipalmitoyl phosphatidylcholine (DPPC) and cholesterol (Chol). Thermodynamic analysis of the surface pressure (π)-area (A) isotherms of the DPPC/Chol systems was performed, which allowed for concluding on miscibility of the components, their molecular packing, and the interactions between molecules. It was found that the most stable system, in which the strongest interactions between molecules occured, was DPPC/Chol at x(Chol)=0.25. The stability of liposomes of the same composition as that in the Langmuir monolayers was analyzed by determining the size distribution of vesicles and the polydispersity as a function of time. The changes of these parameters confirmed that the system of the greatest stability is that with low Chol content.
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Affiliation(s)
- A Szcześ
- Department of Physical Chemistry - Interfacial Phenomena, Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 3, 20031 Lublin, Poland.
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30
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Herculano RD, Pavinatto FJ, Caseli L, D'Silva C, Oliveira ON. The lipid composition of a cell membrane modulates the interaction of an antiparasitic peptide at the air–water interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1907-12. [DOI: 10.1016/j.bbamem.2011.03.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 03/16/2011] [Accepted: 03/22/2011] [Indexed: 10/18/2022]
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31
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van den Driesche S, Witarski W, Pastorekova S, Breiteneder H, Hafner C, Vellekoop MJ. A label-free indicator for tumor cells based on the CH2-stretch ratio. Analyst 2011; 136:2397-402. [PMID: 21499645 DOI: 10.1039/c1an15076f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, we assess the potential of a label-free infrared absorbance based measurement method for determination of the CH(2)-symmetric to CH(2)-antisymmetric stretch ratio, to aid in the detection of the presence of cancer cells and to differentiate between various cancer cells. For this study a normal epithelial kidney cell line, two carcinoma epithelial kidney cell lines, an adult primary human melanocyte cell line, and three human melanoma cell lines were investigated. For the measurements we used a self-designed IR sensor which has the potential to be further developed in a point-of-care instrument. To investigate the mechanism influencing the CH(2)-stretch ratio of mammalian cell membranes, a normal epithelial kidney cell line was exposed to the plasma membrane bound cholesterol reducing agent methyl-β-cyclodextrin. This methodology yielded statistically significant CH(2)-stretch ratio differences between the individual cell lines, normal and tumorous, of both epithelial kidney and melanocyte origin. Measurement results of normal epithelial kidney cells exposed to methyl-β-cyclodextrin indicate that an increase in the CH(2)-stretch ratio arises when there is a decrease in, or redistribution of, the membrane stabilizing agent cholesterol. This study proves that the proposed cell type discrimination method, based on the CH(2)-symmetric to CH(2)-antisymmetric stretch ratio, allows the discrimination between normal and tumor cells. In addition, the method shows high potential for improvement of staging of suspicious tissues.
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Affiliation(s)
- Sander van den Driesche
- Institute of Sensor and Actuator Systems, Vienna University of Technology, Gusshausstrasse 27-29, 1040, Vienna, Austria.
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32
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Chibowski E, Jurak M. Interaction energy of model lipid membranes with water and diiodomethane. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Kett PJN, Casford MTL, Davies PB. Structure of mixed phosphatidylethanolamine and cholesterol monolayers in a supported hybrid bilayer membrane studied by sum frequency generation vibrational spectroscopy. J Phys Chem B 2011; 115:6465-73. [PMID: 21542565 DOI: 10.1021/jp1112685] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The structure of hybrid bilayer membranes (HBMs) containing either a pure cholesterol or mixed cholesterol/dipalmitoylphosphatidylethanolamine (DPPE) proximal layer adsorbed onto an octadecanethiol (ODT) self-assembled monolayer (SAM) on a gold substrate have been investigated by sum frequency generation (SFG) spectroscopy. The HBMs were formed by the adsorption of either a pure cholesterol or mixed DPPE/cholesterol monolayer from the air/water interface of a Langmuir-Blodgett trough at surface pressures of 1, 20, or 40 mN·m(-1). SFG spectra were also recorded of HBMs where cholesterol was replaced by cholesterol-d(7), in which the terminal isopropyl group of the alkyl chain of cholesterol was isotopically labeled. In order to isolate the contribution to the SFG spectra from the cholesterol in the mixed cholesterol/phospholipid films, DPPE-d was used, in which the alkyl chains of the phospholipid were deuterated. The infrared spectra of solvent-cast cholesterol and cholesterol-d(7) films were recorded to aid with assignment of the SFG spectra of the HBMs. Features corresponding to methyl, methylene, and methine stretches of cholesterol were identified in the SFG spectra. Information on the polar orientation of SFG-active groups was obtained from the phases of the spectral features. The structure of the HBMs showed little dependence on the surface pressure at which they were formed. SFG spectra of HBMs with a mixed cholesterol/DPPE proximal layer were very similar to the spectra of HBMs with a pure cholesterol proximal layer, although the features in the spectra were more intense than anticipated for a film with half the number of cholesterol molecules, indicating that DPPE did have some effect on the orientation of cholesterol molecules in the film.
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Affiliation(s)
- P J N Kett
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
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34
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Wang T, Li D, Lu X, Khmaladze A, Han X, Ye S, Yang P, Xue G, He N, Chen Z. Single Lipid Bilayers Constructed on Polymer Cushion Studied by Sum Frequency Generation Vibrational Spectroscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2011; 115:7613-7620. [PMID: 21712964 PMCID: PMC3122884 DOI: 10.1021/jp200546h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Planar solid supported single lipid bilayers on mica, glass, or other inorganic surfaces have been widely used as models for cell membranes. To more closely mimic the cell membrane environment, soft hydrophilic polymer cushions were introduced between the hard inorganic substrate and the lipid bilayer to completely avoid the possible substrate-lipid interactions. In this article, sum frequency generation (SFG) vibrational spectroscopy was used to examine and compare single lipid bilayers assembled on the CaF(2) prism surface and on poly (L-lactic acid) (PLLA) cushion. By using asymmetric lipid bilayers composed of a hydrogenated 1,2-dipalmitoyl-sn-glycerol-3-phosphoglycerol (DPPG) leaflet and a deuterated 1,2-dipalmitoyl-(d62)-sn-glycerol-3-phosphoglycerol (d-DPPG) leaflet, it was shown that the DPPG lipid bilayers deposited on the CaF(2) and PLLA surfaces have similar structures. SFG has also been applied to investigate molecular interactions between an antimicrobial peptide Cecropin P(1) (CP1) and the lipid bilayers on the above two different surfaces. Similar results were again obtained. This research demonstrated that the hydrophilic PLLA cushion can serve as an excellent substrate to support single lipid bilayers. We believe that it can be an important cell membrane model for future studies on transmembrane proteins, for which the possible inorganic substrate-bilayer interactions may affect the protein structure or function.
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Affiliation(s)
- Ting Wang
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dawei Li
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructure, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Xiaolin Lu
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Xiaofeng Han
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Shuji Ye
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Pei Yang
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gi Xue
- State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructure, Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Nongyue He
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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35
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Avery CW, Palermo EF, McLaughlin A, Kuroda K, Chen Z. Investigations of the interactions between synthetic antimicrobial polymers and substrate-supported lipid bilayers using sum frequency generation vibrational spectroscopy. Anal Chem 2011; 83:1342-9. [PMID: 21229969 DOI: 10.1021/ac1025804] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy was used to analyze interactions between solid-supported lipid bilayers acting as models for cellular membranes and several membrane-active random copolymers with different lipophilic side chains, named 0R (no group), 33Me (methyl group), 11Bz (benzyl group), and 33Bu (butyl group), according to both the identity and percentage of the side chains within the polymer. Biological tests of the minimum inhibitory concentration (MIC) and hemolytic concentration were performed. The inherent surface sensitivity of SFG allowed for independent monitoring of isotopically labeled lipid bilayer leaflets as a function of concentration to study polymer-bilayer interaction mechanisms. Concentrations at which each bilayer leaflet was disrupted were quantitatively determined for each copolymer. Spectroscopic evidence of interaction with the bilayer below the critical concentrations was observed for the 11Bz polymer. The lipophilic butyl side chain of the 33Bu polymer was found to be oriented parallel to the surface normal. This research shows that SFG is a useful analytical technique which provides unique details regarding the interaction mechanisms of these membrane-active copolymers and lipid bilayers.
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Affiliation(s)
- Christopher W Avery
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
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36
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Ye S, Nguyen KT, Le Clair SV, Chen Z. In situ molecular level studies on membrane related peptides and proteins in real time using sum frequency generation vibrational spectroscopy. J Struct Biol 2009; 168:61-77. [PMID: 19306928 PMCID: PMC2753614 DOI: 10.1016/j.jsb.2009.03.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 03/11/2009] [Accepted: 03/13/2009] [Indexed: 12/11/2022]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy has been demonstrated to be a powerful technique to study the molecular structures of surfaces and interfaces in different chemical environments. This review summarizes recent SFG studies on hybrid bilayer membranes and substrate-supported lipid monolayers and bilayers, the interaction between peptides/proteins and lipid monolayers/bilayers, and bilayer perturbation induced by peptides/proteins. To demonstrate the ability of SFG to determine the orientations of various secondary structures, studies on the interactions between different peptides/proteins (melittin, G proteins, alamethicin, and tachyplesin I) and lipid bilayers are discussed. Molecular level details revealed by SFG in these studies show that SFG can provide a unique understanding on the interactions between a lipid monolayer/bilayer and peptides/proteins in real time, in situ and without any exogenous labeling.
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Affiliation(s)
- Shuji Ye
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Khoi Tan Nguyen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | | | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
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37
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Avery CW, Som A, Xu Y, Tew GN, Chen Z. Dependence of Antimicrobial Selectivity and Potency on Oligomer Structure Investigated Using Substrate Supported Lipid Bilayers and Sum Frequency Generation Vibrational Spectroscopy. Anal Chem 2009; 81:8365-72. [DOI: 10.1021/ac901271f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Christopher W. Avery
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01002, and PolyMedix, Inc., Radnor, Pennsylvania 19087
| | - Abhigyan Som
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01002, and PolyMedix, Inc., Radnor, Pennsylvania 19087
| | - Yongjiang Xu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01002, and PolyMedix, Inc., Radnor, Pennsylvania 19087
| | - Gregory N. Tew
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01002, and PolyMedix, Inc., Radnor, Pennsylvania 19087
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01002, and PolyMedix, Inc., Radnor, Pennsylvania 19087
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38
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Pavinatto FJ, Pacholatti CP, Montanha EA, Caseli L, Silva HS, Miranda PB, Viitala T, Oliveira ON. Cholesterol mediates chitosan activity on phospholipid monolayers and Langmuir-Blodgett films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10051-10061. [PMID: 19705898 DOI: 10.1021/la901019p] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The polysaccharide chitosan has been largely used in many biological applications as a fat and cholesterol reducer, bactericide agent, and wound healing material. While the efficacy for some of such uses is proven, little is known about the molecular-level interactions involved in these applications. In this study, we employ mixed Langmuir and Langmuir-Blodgett (LB) films of negatively charged dimyristoyl phosphatidic acid (DMPA) and cholesterol as cell membrane models to investigate the role of cholesterol in the molecular-level action of chitosan. Chitosan does not remove cholesterol from the monolayer. The interaction with chitosan tends to expand the DMPA monolayer due to its interpenetration within the film. On the other hand, cholesterol induces condensation of the DMPA monolayer. The competing effects cause the surface pressure isotherms of mixed DMPA-cholesterol films on a chitosan subphase to be unaffected by the cholesterol mole fraction, due to distinct degrees of chitosan penetration into the film in the presence of cholesterol. By combining polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) and sum-frequency generation spectroscopy (SFG), we showed that chitosan induces order into negatively charged phospholipid layers, whereas the opposite occurs for cholesterol. In conclusion, chitosan has its penetration in the film modulated by cholesterol, and electrostatic interactions with negatively charged phospholipids, such as DMPA, are crucial for the action of chitosan.
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Affiliation(s)
- Felippe J Pavinatto
- Instituto de Fisica de São Carlos, Universidade de São Paulo, São Carlos, SP, Brasil
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