title: Spectral and microscopic study of self-assembly of novel cationic spermine amides of betulinic acid.
abstract: Supramolecular characteristics of two spermine amides of betulinic acid (1 and 2) were studied by measuring and evaluating their UV-VIS-NIR spectra in aqueous acetonitrile and DOSY-NMR spectra in tetradeuteromethanol, accompanied by atomic force microscopy (AFM) images, scanning electron microscopy (SEM) micrographs, and transmission electron microscopy (TEM) micrographs. Fibrous supramolecular self-assembly of 1 and 2 was observed by AFM images, as well as by the SEM and TEM micrographs. Bathochromic shifts of the absorbance maximum at 870nm to 1015-970nm in the UV-VIS-NIR spectra were observed with increasing water content in the acetonitrile/water systems, indicating formation of fibrous J-type aggregates. Variable temperature DOSY-NMR spectral measurement showed non-linear dependence that also suggests self-assembly behavior of the studied systems. Chiral supramolecular structures were formed by self-assembling due to the chirality of the monomeric molecules. Application of aqueous media during self-assembly procedures is an important factor in the development of targeted drug delivery systems.
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Isotope Laboratory, Vídeňská 1083, 142 20 Prague 4, Czech Republic; University of Chemistry and Technology, Prague, Department of Chemistry of Natural Compounds, Technická 5, 166 28 Prague 6, Czech Republic.
authors.forename: Uladzimir
authors.initials: U
authors.lastname: Bildziukevich
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Kaletová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Šaman
authors.affiliation: Department of Chemistry, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
authors.forename: Elina
authors.initials: E
authors.lastname: Sievänen
authors.affiliation: Department of Chemistry, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.
authors.forename: Erkki T
authors.initials: ET
authors.lastname: Kolehmainen
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Šlouf
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Isotope Laboratory, Vídeňská 1083, 142 20 Prague 4, Czech Republic; University of Chemistry and Technology, Prague, Department of Chemistry of Natural Compounds, Technická 5, 166 28 Prague 6, Czech Republic. Electronic address: zdenek.wimmer@vscht.cz.
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Wimmer
mesh_terms: D000577:Amides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D064347:Microscopy, Electrochemical, Scanning; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D053978:Pentacyclic Triterpenes; D013096:Spermine / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry*; D000094062:Betulinic Acid
chemical_list: D000577:Amides; D053978:Pentacyclic Triterpenes; D014315:Triterpenes; D013096:Spermine; D000094062:Betulinic Acid
keywords: AFM; Betulinic acid; DOSY-NMR; SEM; Spermine; TEM