writer：Guang Hui Gao, Geun Ho Im, Min Sang Kim, Jae Won Lee, Jehoon Yang, Hyesung Jeon, Jung Hee Lee, Do
keywords：Polymer micelle; imaging
source：期刊
specific source：Small
Issue time：2010年

Nanometer-sized particles are increasingly used for biomedical

applications,[1] as polymeric micelles to carry hydrophobic

imaging markers and/or drugs for disease diagnosis and

therapy.[2] Usually, these polymeric micelles in an aqueous

medium are composed of a hydrophobic core and a hydrophilic

corona, sometimes conjugated with active-targeting ligands

(e.g., antibody, peptides, nucleic acids) that can target the

biomarker of a disease.[2a–c] On the other hand, some polymeric

micelles alone, not conjugated with a targeting ligand, can also

target the pathologic tissue by a stimuli-response mechanism,

with which pH, temperature, or redox can be a stimulus

condition.[3] In this context, a pH-responsive polymeric micelle

is utilized to be reactive in an acidic-pH environment, in which it

is then dissolved. We envisioned that if we encapsulate

magnetite nanoparticles (Fe3O4), which are frequently used

as a contrast agent for magnetic resonance imaging (MRI), into

the pH-responsive polymeric micelle, the resulting Fe3O4-

nanoparticle-loaded pH-responsive polymeric micelle could be

used as a contrast agent for MRI to target and, simultaneously,

image the pH-stimuli tissue, such as cancerous tissue. Herein,

we report a facile and powerful pH-responsive polymeric

micelle that can well encapsulate Fe3O4 nanoparticles, and its

potential applications in medicine for diagnostic imaging of

acidic pathologic areas.