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  • 1
    Electronic Resource
    Electronic Resource
    Surface-enhanced Raman spectroscopy of ellipticines adsorbed onto silver colloids (1992)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 926-931 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100181a072
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    SERS Spectra of Polythiophene in Doped and Undoped States (1995)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 6628-6634 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100017a052
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Atomic force microscopy of human serum albumin (HSA) on poly(styrene/acrolein) microspheres (1996)
    Springer
    Colloid & polymer science 274 (1996), S. 513-519 
    Details
    ISSN: 1435-1536
    Keywords: Atomic force microscopy ; human serum albumin ; poly (styrene/acrolein) microspheres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Atomic Force Microscopy (AFM) in the tapping mode was used for the observation of bare poly (styrene/acrolein) P(SA) microspheres and microspheres with attached HSA. Prior to the AFM observations the P(SA) microspheres were immobilized covalently on the surface of quartz slides modified with γ-aminopropyltriethoxysilane. Atomic Force Microscopy pictures were registered for the dry samples. The partial coalescence of the P(SA) microspheres connected to the quartz surface with amino groups has been observed. The AFM pictures of the single P(SA) microspheres revealed that the surface of these particles is smooth and that any irregularities, if present, do not exceed 1 nm. The surface of microspheres with attached HSA has very clearly different morphology with regular pattern of HSA macromolecules. Cracks on the surfaces of some microspheres with HSA revealed that protein macromolecules are attached to these particles in several layers. In the case of some other microspheres the defects in protein attachment allowed the observation of the border between the bare surface of the P(SA) microspheres and the surface covered with protein macromolecules. Comparison of the thickness of the HSA layers on the P(SA) microspheres with the dimensions of HSA macromolecules, determined earlier from the x-ray studies, suggests that the first layer, 3.0±0.2 nm thick, is formed of the HSA macromolecules arranged flatly on the surface whereas protein macromolecules in the subsequent layers, each 8.6±1 nm thick, are adsorbed protruding from the surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655225
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Surface morphology of polypyrrole core/polyacrolein shell latex by atomic force microscopy (AFM) (1998)
    Springer
    Colloid & polymer science 276 (1998), S. 34-39 
    Details
    ISSN: 1435-1536
    Keywords: Key words Atomic force microscopy ; core-shell latex ; polypyrrole ; polyacrolein ; surface morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Polypyrrole latex (P(P)), synthesized in Redox polymerization of pyrrole, was used as seed for radical polymerization of acrolein initiated with K2S2O8. In this process the polypyrrole core/polyacrolein shell latex (P(P–A)) was obtained. Morphology of the surface of P(P–A) particles was investigated by atomic force microscopy (AFM). It was found that macromolecules of polyacrolein are not randomly distributed on the surface of polypyrrole but form patches. Apparently, attraction between macromolecules of poly-acrolein in the surface layer is high and the enthalpy of formation of polyacrolein macromolecule clusters is sufficient to compensate, at least, the negative entropy change due to ordering of these macromolecules. Thickness of the polyacrolein layer on the surface of polypyrrole particles, which were covered only partially with polyacrolein, was equal to only 1.6 nm (standard deviation σ= 0.2 nm) and thus, it was reasonable to assume that it corresponded to the monolayer coverage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050205
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  • 5
    Electronic Resource
    Electronic Resource
    Surface-enhanced Raman spectroscopy of ellipticine, 2-N-methylellipticinium and their complexes with DNA (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 373-377 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Surface-enhanced Raman spectroscopy (SERS) in silver colloidal solutions of ellipticine, 2-N-methylellipticinium and their complexes with DNA were investigated. On varying the pH of silver sols, large spectral changes are observed in the SER spectra of ellipticine which are related to the reversible transformation between the neutral and protonated forms. From intensity measurements the protonation pK of ellipticine absorbed on silver collo ds was estimated (ca. 7.5). This value is very close to that previously obtained in a pure aqueous medium from UV-visible absorption and fluorescence data. This indicates that the interstion of ellipticine with the silver surface does not perturb the protonation equilibrium at N-2. The intensity changes observed in the SER spectrum of the ellipticine-DNA complex at pH 8.5 are interpreted as arising from a shift of the protonation equilibrium in the presence of DNA (pKa ≈ 8.6) and not from perturbations induced by intercalation of the drug between base pairs. The results of this study suggest that adsorption of ellipticine (and the ellipticinium derivative) on silver colloids takes place through the indole moiety with the chromophore plane perpendicular to the silver surface.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250230702
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    SER spectra of acridine and acridinium ions in colloidal silver sols. Electrolytes and PH effects (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 24 (1993), S. 745-752 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Extensive surface-enhanced Raman (SER) spectra of acridine and acridinium ions, taken as probes of DNA intercalating agents, were investigated in colloidal silver sols. From comparison of the SER and Fourier transform near-IR Raman spectra, it is confirmed that acridine is adsorbed on the metal surface via its protonatable nitrogen atom with its plane perpendicular to the surface. The effects of the electrolyte composition of silver sols, the laser excitation wavelengths and the solution pH were carefully investigated. When present in the solution, halide ions increase the SER signal intensity and shift the nitrogen protonation towards high pH values. Moreover, SER spectra of acridinium (AH+) show a higher signal-to-noise ratio than those of the neutral species and this is particularly pronounced when halides ions are present in the silver sols. The additional enhancement probably originates from a resonant charge transfer which appears to be more efficient when AH+ species forms an ion pair with halide ions. The pKa of acridine on a silver surface was estimated from titration curves based on the intensity ratios of lines at ca. 1564 and ca. 1584 cm-1, characteristic of the neutral and the protonated species, respectively. The titration curves behave quadratically or linearly according to whether the silver sols do or do not contain halide ions. On the basis of the phenomenological electrochemical model, the pH was found to change more slowly in the double layer than in the bulk solution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250241105
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    Paper (German National Licenses)
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