PEG-g-poly(GdDTPA-co-L-cystine): Effect of PEG chain length on in vivo contrast enhancement in MRI

Aaron M. Mohs, Yuda Zong, Junyu Guo, Dennis L. Parker, Zheng Rong Lu

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

Biodegradable macromolecular Gd(III) complexes, Gd-DTPA cystine copolymers (GDCP), were grafted with PEG of different sizes to modify the physicochemical properties and in vivo MRI contrast enhancement of the agents and to study the effect of PEG chain length on these properties. Three new PEG-grafted biodegradable macromolecular gadolinium(III) complexes were synthesized and characterized as blood pool MRI contrast agents. One of three different lengths of MPEG-NH2 (MW = 550, 1000, and 2000) was grafted to the backbone of GDCP to yield PEGn-g-poly(GdDTPA-co-L-cystine), PEGn,-GDCP. The PEG chain length did not dramatically alter the T1 relaxivity, r1, of the modified agents. The MRI enhancement profile of PEGn-GDCP with different PEG sizes was significantly different in mice with respect to both signal intensity and clearance profiles. PEG2000-GDCP showed more prominent enhancement in the blood pool for a longer period of time than either PEG1000-GDCP or PEG550-GDCP. In the kidney, PEG2000-GDCP had less enhancement at 2 min than PEG1000-GDCP, but both PEG550-GDCP and PEG1000-GDCP showed a more pronounced signal decay thereafter. The three agents behaved similarly in the liver, as compared to that in the heart. All three agents showed little enhancement in the muscle. Chemical grafting with PEG of different chain lengths is an effective approach to modify the physiochemistry and in vivo contrast enhancement dynamics of the biodegradable macromolecular contrast agents. The novel agents are promising for further clinical development for cardiovascular and cancer MR imaging.

Original languageEnglish (US)
Pages (from-to)2305-2311
Number of pages7
JournalBiomacromolecules
Volume6
Issue number4
DOIs
StatePublished - Jul 2005

ASJC Scopus subject areas

  • Bioengineering
  • Biomaterials
  • Polymers and Plastics
  • Materials Chemistry

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