A cancer-recognizable MRI contrast agents using pH-responsive polymeric micelle

Biomaterials. 2014 Jan;35(1):337-43. doi: 10.1016/j.biomaterials.2013.10.004. Epub 2013 Oct 15.

Abstract

A cancer-recognizable MRI contrast agents (CR-CAs) has been developed using pH-responsive polymeric micelles. The CR-CAs with pH sensitivity were self-assembled based on well-defined amphiphilic block copolymers, consisting of methoxy poly(ethylene glycol)-b-poly(L-histidine) (PEG-p(L-His)) and methoxy poly(ethylene glycol)-b-poly(L-lactic acid)-diethylenetriaminopentaacetic acid dianhydride-gadolinium chelate (PEG-p(L-LA)-DTPA-Gd). The CR-CAs have a spherical shape with a uniform size of ~40 nm at physiological pH (pH 7.4). However, in acidic tumoral environment (pH 6.5), the CR-CAs were destabilized due to the protonation of the imidazole groups of p(L-His) blocks, causing them to break apart into positively charged water-soluble polymers. As a result, the CR-CAs exhibit highly effective T1 MR contrast enhancement in the tumor region, which enabled the detection of small tumors of ~3 mm(3 )in vivo at 1.5 T within a few minutes.

Keywords: Cancer diagnosis; Imaging agents; Magnetic resonance imaging; Micelles; pH-responsive materials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Contrast Media*
  • Humans
  • Hydrogen-Ion Concentration*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Micelles*
  • Microscopy, Confocal
  • Particle Size
  • Polymers*

Substances

  • Contrast Media
  • Micelles
  • Polymers