In Vivo Positive Magnetic Resonance Imaging of Brain Cancer (U87MG) Using Folic Acid-Conjugated Polyacrylic Acid-Coated Ultrasmall Manganese Oxide Nanoparticles

Featured Application Cancer-targeting T-1 magnetic resonance imaging contrast agent. Ultrasmall nanoparticles are potential candidates for application as high-performance imaging agents. Herein, we present the synthesis and characterization of folic acid (FA)-conjugated polyacrylic acid (PAA)-coated MnO nanoparticles with an average particle diameter of 2.7 nm. FA conferred cancer-targeting ability, while PAA conferred good colloidal stability and low cellular cytotoxicity on the FA-PAA-coated MnO nanoparticles. Further, the nanoparticles exhibited a high relaxivity (r(1)) value of 9.3 s(-1)mM(-1) (r(2)/r(1) = 2.2). Their application potential as cancer-targeting T-1 magnetic resonance imaging contrast agents was confirmed by their enhanced T-1 contrast enhancements at the brain cancer (U87MG) site upon intravenous administration to mice tails.