Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5353127 | Applied Surface Science | 2016 | 7 Pages |
Abstract
Superparamagnetic iron oxide nanoparticles (SPIONs) as T2 contrast agents have great potential to sense calcium ion (Ca2+) using magnetic resonance imaging (MRI). Here we prepared calcium-responsive SPIONs for MRI, formed by combining poly(ethylene glycol) (PEG) and polyethylenimine (PEI) coated iron oxide nanoparticle (PEI/PEG-SPIONs) contrast agents with the straightforward calcium-sensing compound EGTA (ethylene glycol tetraacetic acid). EGTA was conjugated onto PEI/PEG-SPIONs using EDC/sulfo-NHS method. EGTA-SPIONs were characterized using TEM, XPS, DSL, TGA and SQUIID. DSL results show that the SPIONs aggregate in the presence of Ca2+. MRI analyses indicate that the water proton T2 relaxation rates in HEPES suspensions of the EGTA-SPIONs significantly increase with the calcium concentration because the SPIONs aggregate in the presence of Ca2+. The T2 values decreased 25% when Ca2+ concentration decreased from 1.2 to 0.8Â mM. The aggregation of EGTA-SPIONs could be reversed by EDTA. EGTA-SPIONs have potential as smart contrast agents for Ca2+-sensitive MRI.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Pengfei Xu, Zhiwei Shen, Baolin Zhang, Jun Wang, Renhua Wu,