Peptide and Gd Complexes Containing Colloidal Assemblies as Tumor-Specific Contrast Agents in MRI: Physicochemical Characterization

Research output: Contribution to journalArticle

Abstract

The aggregation behavior of an amphiphilic supramolecular system, with potential application as a tumor-specific magnetic resonance imaging contrast agent, has been studied in detail by dynamic light scattering, small-angle neutron scattering and cryotransmission electron microscopy. The system was constituted of mixed aggregates formed by an anionic unimer containing the DTPAGlu, a chelating agent for the paramagnetic Gd3+ ion, and an uncharged unimer containing the bioactive peptide CCK8, capable of directing the assembly toward tumor cells. Mixed aggregates formed by both unimers, and in the case of the DTPAGlu unimer with the chelating agent as free base or as Gd3+ complex, have been investigated. A number of interesting features of the aggregation behavior were revealed: at physiological pH, micelles and bilayer structures were present, whereas upon decreasing solution pH or increasing ionic strength, the formation of bilayer structures was favored. On the basis of the above observations, the aggregating mechanism has been elucidated by considering the screening effect on intra- and interaggregate electrostatic repulsions.

Details

Authors
  • Mauro Vaccaro
  • Antonella Accardo
  • Gerardino D'Errico
  • Karin Schillén
  • Aurel Radulescu
  • Diego Tesauro
  • Giancarlo Morelli
  • Luigi Paduano
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biophysics

Keywords

  • SYSTEM, RECEPTORS, DIFFUSION, HIGH-RELAXIVITY, AQUEOUS-SOLUTION, LIGHT-SCATTERING, ANGLE NEUTRON-SCATTERING
Original languageEnglish
Pages (from-to)1736-1746
JournalBiophysical Journal
Volume93
Issue number5
Publication statusPublished - 2007
Publication categoryResearch
Peer-reviewedYes