Bio-Inspired, Melanin-Like Nanoparticles as a Highly Efficient Contrast Agent for <i>T</i>₁-Weighted Magnetic Resonance Imaging

다국어 초록 (Multilingual Abstract)

<P>The development of nontoxic and biocompatible imaging agents will create new opportunities for potential applications in clinical MRI diagnosis. Synthetic melanin-like nanoparticles (MelNPs), analogous to natural sepia melanin (a major component of the cuttlefish ink), can be used as contrast agent for MRI. MelNPs complexed with paramagnetic Fe<SUP>3+</SUP> ions show much higher relaxivity values than existing MRI <I>T</I><SUB>1</SUB> contrast agents based on gadolinium (Gd) or manganese (Mn); MelNP values at 3T were <I>r</I><SUB>1</SUB> = 17 and <I>r</I><SUB>2</SUB> = 18 mM<SUP>–1</SUP> s<SUP>–1</SUP> (<I>r</I><SUB>2</SUB>/<I>r</I><SUB>1</SUB> value of 1.1). With significant enhancement to MRI contrast, this biomimetic approach using MelNPs functionalized with paramagnetic Fe<SUP>3+</SUP> ions and surface-modified with biocompatible poly(ethylene glycol) units, could provide new insight into how melanin-based bioresponsive and therapeutic imaging probes integrate with their various biological functions.</P><P><B>Graphic Abstract</B>
<IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bomaf6/2013/bomaf6.2013.14.issue-10/bm4008138/production/images/medium/bm-2013-008138_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/bm4008138'>ACS Electronic Supporting Info</A></P>