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Peptide Derivatized Lamellar Aggregates as Target‐Specific MRI Contrast Agents
Author(s) -
Tesauro Diego,
Accardo Antonella,
Gianolio Eliana,
Paduano Luigi,
Teixeira José,
Schillén Karin,
Aime Silvio,
Morelli Giancarlo
Publication year - 2007
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200700077
Subject(s) - micelle , lamellar structure , chemistry , amphiphile , peptide , gadolinium , bilayer , monomer , supramolecular chemistry , peg ratio , lipid bilayer , crystallography , biophysics , organic chemistry , membrane , polymer , copolymer , biochemistry , crystal structure , aqueous solution , finance , economics , biology
The relaxivity behaviour and the structural characterization of new supramolecular aggregates (bilayer structures and micelles) obtained by combining two different amphiphilic monomers are reported. One monomer, (C18) 2 DTPAGlu‐Gd, contains a very stable gadolinium complex, and the other, DSPE‐PEG 2000 ‐CCK8, contains the bioactive CCK8 peptide. Samples that contained only DSPE‐PEG 2000 ‐CCK8, or up to 50 % (C18) 2 DTPAGlu‐Gd, aggregated as double‐layer structures (lamellar aggregates) with a thickness of∼80–100 Å, as evaluated by SANS measurement and Cryo‐TEM imaging. A transition to micelle formation was observed when the amount of (C18) 2 DTPAGlu‐Gd in the aggregate was increased. These were rod‐like micelles ∼40 Å in radius and >200 Å in length. The proton relaxivities for both lamellar aggregates and rod‐like micelles were the same (17.2 m M −1 s −1 ), although the values were the results of different combinations of local and global contributions. The in vitro target selectivity of aggregates that contained the CCK‐8 peptide was demonstrated by using nuclear medicine techniques.