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Zappacosta R, Di Giulio M, Ettorre V, Bosco D, Hadad C, Siani G, Di Bartolomeo S, Cataldi A, Cellini L, Fontana A. Liposome-induced exfoliation of graphite to few-layer graphene dispersion with antibacterial activity. J Mater Chem B 2015; 3:6520-6527. [DOI: 10.1039/c5tb00798d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Liposome-induced exfoliation of graphite allowed to obtain few-layer graphene homogeneous in size and hydrophilic due to the non-covalent functionalization with phospholipids. The corresponding dispersions are stable for 48 h and demonstrate antimicrobial activity.
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Affiliation(s)
- R. Zappacosta
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
| | - M. Di Giulio
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
| | - V. Ettorre
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
| | - D. Bosco
- Istituto di Genetica Molecolare
- CNR unità di Chieti
- I-66100 Chieti
- Italy
| | - C. Hadad
- Center of Excellence for Nanostructured Materials (CENMAT)
- INSTM
- Unit of Trieste
- Dipartimento di Scienze Chimiche e Farmaceutiche
- Università di Trieste
| | - G. Siani
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
| | - S. Di Bartolomeo
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
| | - A. Cataldi
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
| | - L. Cellini
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
| | - A. Fontana
- Dipartimento di Farmacia
- Università ‘G. d'Annunzio’
- 66100 Chieti
- Italy
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2
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Zhou Y, Liu CH, Sun Y, Pu Y, Boydston-White S, Liu Y, Alfano RR. Human brain cancer studied by resonance Raman spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:116021. [PMID: 23154776 PMCID: PMC3499405 DOI: 10.1117/1.jbo.17.11.116021] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 10/22/2012] [Accepted: 10/22/2012] [Indexed: 05/22/2023]
Abstract
The resonance Raman (RR) spectra of six types of human brain tissues are examined using a confocal micro-Raman system with 532-nm excitation in vitro. Forty-three RR spectra from seven subjects are investigated. The spectral peaks from malignant meningioma, stage III (cancer), benign meningioma (benign), normal meningeal tissues (normal), glioblastoma multiforme grade IV (cancer), acoustic neuroma (benign), and pituitary adenoma (benign) are analyzed. Using a 532-nm excitation, the resonance-enhanced peak at 1548 cm-1 (amide II) is observed in all of the tissue specimens, but is not observed in the spectra collected using the nonresonance Raman system. An increase in the intensity ratio of 1587 to 1605 cm-1 is observed in the RR spectra collected from meningeal cancer tissue as compared with the spectra collected from the benign and normal meningeal tissue. The peak around 1732 cm-1 attributed to fatty acids (lipids) are diminished in the spectra collected from the meningeal cancer tumors as compared with the spectra from normal and benign tissues. The characteristic band of spectral peaks observed between 2800 and 3100 cm-1 are attributed to the vibrations of methyl (─CH3) and methylene (─CH2─) groups. The ratio of the intensities of the spectral peaks of 2935 to 2880 cm-1 from the meningeal cancer tissues is found to be lower in comparison with that of the spectral peaks from normal, and benign tissues, which may be used as a distinct marker for distinguishing cancerous tissues from normal meningeal tissues. The statistical methods of principal component analysis and the support vector machine are used to analyze the RR spectral data collected from meningeal tissues, yielding a diagnostic sensitivity of 90.9% and specificity of 100% when two principal components are used.
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Affiliation(s)
- Yan Zhou
- The Air Force General Hospital, PLA, No. 30 Fuchenglu, Haidian District, Beijing 100142, China
| | - Cheng-Hui Liu
- The City College of the City University of New York, Institute of Ultrafast Spectroscopy and Lasers, Department of Physics, New York, New York 10031
- Address all correspondence to: Cheng-hui Liu, The City College of the City University of New York, Institute of Ultrafast Spectroscopy and Lasers, Department of Physics, New York, New York 10031. Tel: 212-650-5531; E-mail:
| | - Yi Sun
- The City College of the City University of New York, Department of Electrical Engineering, New York, New York 10031
| | - Yang Pu
- The City College of the City University of New York, Institute of Ultrafast Spectroscopy and Lasers, Department of Physics, New York, New York 10031
| | - Susie Boydston-White
- City University of New York, Borough of Manhattan Community College, Science Department, New York, New York 10007-1097
| | - Yulong Liu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Robert R. Alfano
- The City College of the City University of New York, Institute of Ultrafast Spectroscopy and Lasers, Department of Physics, New York, New York 10031
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3
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Lamberson ER, Cambrea LR, Rochet JC, Hovis JS. Path dependence of three-phase or two-phase end points in fluid binary lipid mixtures. J Phys Chem B 2009; 113:3431-6. [PMID: 19243147 DOI: 10.1021/jp810326w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The phase behavior of anionic/zwitterionic mixtures can be controlled by tuning the charge state of the anionic lipid. In the case of dioleoylphosphatidic acid (DOPA)/dioleoylphosphatidylcholine (DOPC) mixtures, demixing occurs either when DOPA is protonated or when DOPA(2-):Ca(2+) complexes form. Herein it will be shown that the final end point, a three-phase or two-phase system, depends on the order in which the charge state is manipulated. The facile accessibility of different end points is a clear demonstration of the inherent flexibility of biological systems.
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Affiliation(s)
- Emily R Lamberson
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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4
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Procházka M, Stĕpánek J, Turpin PY. Interaction of phospholipid dispersions with water-soluble porphyrins as monitored by their Raman temperature profiles. Chem Phys Lipids 2004; 132:145-56. [PMID: 15555601 DOI: 10.1016/j.chemphyslip.2004.06.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 06/04/2004] [Accepted: 06/11/2004] [Indexed: 11/21/2022]
Abstract
Raman scattering spectra of 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) dispersions, mixed with water-soluble porphyrins, i.e. cationic copper(II)-5,10,15,12-tetrakis(4-N-methylpyridyl) and anionic silver(II)-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrins, were measured in the 2800-3100 cm(-1) C-H stretching vibration region as a function of the temperature within the 5-55 degrees C range. Temperature profiles of Raman data were constructed from a quantitative data treatment based on factor analysis. This method is shown to be more efficient than the commonly used approach employing peak intensity ratios. Parameters of the gel phase to liquid crystal phase transition determined from Raman temperature profiles were used to monitor the porphyrin influence on DPPG and DPPC structures. Both negatively and positively charged porphyrins significantly perturb DPPC and DPPG dispersions, causing significant downshift of the transition temperature and broadening of the transition region. Water-soluble porphyrins are assumed to set at the outside part of phospholipid dispersions and interact via coulombic forces with charged lipid heads. For the cationic CuTMPyP, the strongest effect has been observed for negatively charged DPPG. In contrast, anionic AgTPPC4 has been found to interact more efficiently with DPPC possessing both positive and negative charges.
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Affiliation(s)
- Marek Procházka
- L. P. B. C. (CNRS UMR 7033), Université Pierre et Marie Curie, 4 Place Jussieu, Case 138, F-75252 Paris Cedex 05, France.
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5
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Estrela-Lopis I, Brezesinski G, Möhwald H. Miscibility of DPPC and DPPA in monolayers at the air/water interface. Chem Phys Lipids 2004; 131:71-80. [PMID: 15210366 DOI: 10.1016/j.chemphyslip.2004.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2003] [Revised: 03/23/2004] [Accepted: 04/05/2004] [Indexed: 10/26/2022]
Abstract
Monolayers of mixtures of 1,2-dipalmitoylphosphatidylcholine (DPPC) as the substrate and 1,2-dipalmitoylphosphatidic acid (DPPA) as the product of the hydrolysis reaction catalyzed by phospholipase D (PLD) were investigated in the presence of Ca2+. The miscibility behavior and the microstructure of mixed domains have been studied by grazing incidence X-ray diffraction (GIXD), Brewster angle microscopy and film balance measurements. The phase diagram reveals partial miscibility on both sides and a wide miscibility gap, which becomes narrower at high pressure. At low pressure, the segregation of condensed DPPA-rich domains in a fluid-like DPPC matrix was detected already at small DPPA concentrations and their structure was determined. A small amount of DPPC mixed into the segregated DPPA domains induces the transformation from rectangular to an oblique unit cell and increases the tilt angle in the condensed domains. At high pressure, two types of condensed phase domains were found: DPPC-rich and DPPA-rich. A drastic reduction of the tilt angle in the DPPC-rich domains with increasing amount of DPPA was observed. The decrease of the tilt angle must be connected with a change of the head group conformation of DPPC in such mixed domains.
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Affiliation(s)
- I Estrela-Lopis
- Institute for Medical Physics and Biophysics, University of Leipzig, Liebigstr. 27, D-04103 Leipzig, Germany
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6
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Dimitrova MN, Matsumura H, Dimitrova A, Neitchev VZ. Interaction of albumins from different species with phospholipid liposomes. Multiple binding sites system. Int J Biol Macromol 2000; 27:187-94. [PMID: 10828364 DOI: 10.1016/s0141-8130(00)00123-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interactions of three serum albumin species (rat, human, and bovine) with liposomes containing dimyristoylphosphatidylcholine, distearoylphosphatidylcholine or mixtures of both under different membrane fluidity conditions have been investigated using isothermal titration calorimetry and steady-state fluorescence anisotropy. Calorimetric titration studies of the binding of liposomes to the albumin species indicate in all cases exothermic processes with multiple sites of binding in the albumin molecules. Distinct saturation of the protein-lipid binding processes was observed at low or high molar lipid/protein ratio depending on the particular system. The thermodynamic parameters, including the association enthalpy and entropy, and the optimal values for the binding constants were thoroughly varied as a function of the number of identical binding sites, defining the best value of the parameter. Our experimental results, obtained using complementary biophysical techniques, provide experimental evidence for a significant difference in the association of the three protein species to phospholipid membranes. These observations also suggest a close relation between the binding parameters of the protein/lipid association and the lipid state of the phospholipid membranes.
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Affiliation(s)
- M N Dimitrova
- Electrotechnical Laboratory, AIST, MITI, 305 8568, Tsukuba, Japan
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7
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Lipid Model Membranes and Biomembranes. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1573-4374(99)80006-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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8
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Takahashi H, Yasue T, Ohki K, Hatta I. Structural and thermotropic properties of calcium-dimyristoylphosphatidic acid complexes at acidic and neutral pH conditions. Biophys J 1995; 69:1464-72. [PMID: 8534817 PMCID: PMC1236377 DOI: 10.1016/s0006-3495(95)80016-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Two kinds of calcium-dimyristoylphosphatidic acid (DMPA) complexes at acidic and neutral pH conditions were prepared in the following ways. The complex at pH 4 was obtained by adding Ca2+ to DMPA dispersion in pure water. On the other hand, the complex at pH 7.4 was obtained by adding Ca2+ to DMPA dispersion in the presence of NaOH. The stoichiometries of Ca2+ ion to DMPA molecule are 0.5-0.67 and approximately 1 for the complexes at pH 4 and 7.4, respectively. Static x-ray diffraction shows that the hydrocarbon chains of the Ca(2+)-DMPA complex at pH 4 at 20 degrees C are more tightly packed than those of the complex at pH 7.4 at 20 degrees C. Furthermore, the complex at pH 4 at 20 degrees C gives rise to several reflections that might be related to the ordered arrangement of the Ca2+ ions. These results indicate that the structure of the complex at pH 4 is crystalline-like. In the differential scanning calorimetry (DSC) thermogram, the complex at pH 7.4 undergoes no phase transition in a temperature range between 30 and 80 degrees C. On the other hand, in the DSC thermogram for the complex at pH 4, a peak appears at 65.8 degrees C in the first heating scan. In the successive second heating scan, a transition peak appears at 63.5 degrees C. In connection with the DSC results, the structural changes associated with these phase transitions were studied with temperature-scan x-ray diffraction. In the first heating scan, although a peak appears at 65.80C in the DSC thermogram, the hydrocarbon chain packing gradually converts from an orthorhombic lattice to a hexagonal lattice near 52 degree C, and successively the chain melting phase transition occurs near 670C. In the second heating scan, the hydrocarbon chains are packed in a hexagonal lattice over the whole temperature range and the chain melting phase transition occurs near 63.5 degree C. Therefore,the Ca2+-DMPA complex at pH 4 has a metastable state. The metastable state transforms to a stable state by maintaining the complex at pH 4 for about 90 h at 200C.
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Affiliation(s)
- H Takahashi
- Department of Applied Physics, School of Engineering, Nagoya University, Japan
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9
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Zhang F, Rowe ES. Calorimetric studies of the interactions of cytochrome c with dioleoylphosphatidylglycerol extruded vesicles: ionic strength effects. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1193:219-25. [PMID: 8054342 DOI: 10.1016/0005-2736(94)90156-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cytochrome c has been studied as an example of a peripheral membrane protein which interacts with the lipids as well as the proteins of the inner mitochondrial membrane. In order to elucidate the thermodynamic properties of these interactions, isothermal titration calorimetry and differential scanning calorimetry (DSC) were used to study the binding of cytochrome c to negatively charged dioleoylphosphatidylglycerol (DOPG) extruded vesicles as a function of ionic strength. The binding constant and enthalpy of association decrease with increasing ionic strength, with no binding detected above 0.5 M NaCl. The enthalpy of the binding of cytochrome c to DOPG-extruded vesicles was 15 kcal/mol, and the binding constant was 6 x 10(6) M-1 at the lowest ionic strengths. The minimum size of the lipid cluster to which the protein bound was found to be approx. 9 lipid molecules in the titration calorimetry measurements and as low as 5 lipid molecules in the DSC measurements. The stability of the bound cytochrome c was found to be reduced; the thermal denaturation temperature was lowered from 83 to 50 degrees when bound to DOPG. The results of this study support previous suggestions that cytochrome c may undergo a conformational change when it binds to charged lipids such as DOPG. The results also support the suggestion that the protein penetrates partially into the lipid bilayer.
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Affiliation(s)
- F Zhang
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66103
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10
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Vincent JS, Revak SD, Cochrane CD, Levin IW. Interactions of model human pulmonary surfactants with a mixed phospholipid bilayer assembly: Raman spectroscopic studies. Biochemistry 1993; 32:8228-38. [PMID: 8347622 DOI: 10.1021/bi00083a025] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The temperature dependence and acyl chain packing properties of the binary lipid mixtures of dipalmitoylphosphatidylcholine-d62 (DPPC-d62)/dipalmitoylphosphatidylglycerol (DPPG) multilayers, reconstituted with two synthetic peptides for modeling the membrane behavior of the SP-B protein associated with human pulmonary surfactant, were investigated by vibrational Raman spectroscopy. The synthetic peptides consisted of 21 amino acid residues representing repeating charged units of either lysine or aspartic acid separated by hydrophobic domains consisting of four leucines (KL4 or DL4, respectively). These peptides were designed to mimic the alternating hydrophobic and hydrophilic sequences defining the low molecular weight SP-B protein. Raman spectroscopic parameters consisting of integrated band intensities, line widths, and relative peak height intensity ratios were used to probe the bilayer order/disorder characteristics of the liposomal perturbations reflected by the reconstituted membrane assemblies. Temperature profiles derived from the various Raman intensity parameters for the 3100-2800-cm-1 carbon-hydrogen (C-H) and the 2000-2300-cm-1 carbon-deuterium (C-D) stretching mode regions, spectral intervals representative of acyl chain vibrations, reflected lipid reorganizations specific to peptide interactions with either the DPPC-d62 or DPPG component of the liposome. For the multilamellar surfactant systems composed of either KL4 or DL4 reconstituted with the binary DPPG/DPPC-d62 lipid mixture, the breadth of the gel to liquid crystalline phase transition temperatures TM, defined by acyl chain C-H and C-D stretching mode order/disorder parameters, increased from about 1 degree C in the peptide-free systems to over 10 degrees C. This breadth in TM indicates an increased lipid disorder and a distinct noncooperative chain melting process for the model liposomes. In comparing the interactions of the synthetic peptides with DPPG/DPPC mixtures and with DPPC liposomes alone, the negatively charged DL4 peptide perturbs the DPPG component of the lipid mixture more strongly than the DPPC-d62 component; moreover, the DL4 peptide disrupts the structure of the DPPG lipid domains in the binary mixture to a greater extent than the KL4 peptide. The microdomain heterogeneity of the binary lipid mixture arising from lipid-peptide interactions is discussed in terms of the Raman spectral properties of the multilayers. The Raman data in conjunction with previous bubble surfactometer and animal studies (Cochrane & Revak, 1991) suggest that lipid domain structures are present in functional surfactants and that the dynamic bilayer microheterogeneity induced by the surfactant peptide or protein is essential for pulmonary mechanics.
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Affiliation(s)
- J S Vincent
- Chemistry Department, University of Maryland Baltimore County, Catonsville 21228
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