Issue 25, 2016

pH-Responsive biodegradable polymeric micelles with anchors to interface magnetic nanoparticles for MR imaging in detection of cerebral ischemic area

Abstract

A novel type of pH-responsive biodegradable copolymer was developed based on methyloxy-poly(ethylene glycol)-block-poly[dopamine-2-(dibutylamino) ethylamine-L-glutamate] (mPEG-b-P(DPA-DE)LG) and applied to act as an intelligent nanocarrier system for magnetic resonance imaging (MRI). The mPEG-b-P(DPA-DE)LG copolymer was synthesized by a typical ring opening polymerization of N-carboxyanhydrides (NCAs-ROP) using mPEG-NH2 as a macroinitiator, and two types of amine-terminated dopamine groups and pH-sensitive ligands were grafted onto a side chain by a sequential aminolysis reaction. This design greatly benefits from the addition of the dopamine groups to facilitate self-assembly, as these groups can act as high-affinity anchors for iron oxide nanoparticles, thereby increasing long-term stability at physiological pH. The mPEG moiety in the copolymers helped the nanoparticles to remain well-dispersed in an aqueous solution, and pH-responsive groups could control the release of hydrophobic Fe3O4 nanoparticles in an acidic environment. The particle size of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles was measured by dynamic light scattering (DLS) and cryo-TEM. The superparamagnetic properties of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles were confirmed by a superconducting quantum interference device (SQUID). T2-weighted magnetic resonance imaging (MRI) of Fe3O4-loaded mPEG-b-P(DPA-DE)LG phantoms exhibited enhanced negative contrast with an r2 relaxivity of approximately 106.7 mM−1 s−1. To assess the ability of the Fe3O4-loaded mPEG-P(DE-DPA)LG micelles to act as MRI probes, we utilized a cerebral ischemia disease rat model with acidic tissue. We found that a gradual change in contrast in the cerebral ischemic area could be visualized by MRI after 1 h, and maximal signal loss was detected after 24 h post-injection. These results demonstrated that the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles can act as pH-triggered MRI probes for diagnostic imaging of acidic pathological tissues.

Graphical abstract: pH-Responsive biodegradable polymeric micelles with anchors to interface magnetic nanoparticles for MR imaging in detection of cerebral ischemic area

Supplementary files

Article information

Article type
Paper
Submitted
22 Gwen. 2015
Accepted
25 Du 2015
First published
26 Du 2015

Nanoscale, 2016,8, 12588-12598

Author version available

pH-Responsive biodegradable polymeric micelles with anchors to interface magnetic nanoparticles for MR imaging in detection of cerebral ischemic area

H. Y. Yang, M. Jang, G. H. Gao, J. H. Lee and D. S. Lee, Nanoscale, 2016, 8, 12588 DOI: 10.1039/C5NR06542A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements