Relaxometric, Optical and Cell Viability Properties of D-Glucuronic Acid Coated Cr2O3 Nanoparticles

D-glucuronic acid-coated ultrasmall chromium oxide (Cr2O3) nanoparticles were synthesized by a one-pot polyol method and their relaxometric and optical properties were investigated. The assynthesized D-glucuronic acid-coated nanoparticles were amorphous owing to ultrasmall particle diameters (d(avg) = 2.0 nm), whereas orthorhombic Cr2O3 nanoparticles with two size groups (davg = 3.6 and 5.7 nm) were observed after thermogravimetric analysis (900 degrees C) as a result of particle growth. The nanoparticles exhibited size-dependent UV-visible absorption maxima at 238, 274, and 372 nm with increasing particle diameter, corresponding to band gaps of 5.13, 4.45, and 3.28 eV, respectively. D-glucuronic acid-coated ultrasmall Cr2O3 nanoparticles revealed low water proton relaxivities of r(1) = 0.05 s(-1)mM(-1) and r(2) = 20 s(-1)mM(-1), consistent with the antiferromagnetic property of Cr2O3. They showed good biocompatibility up to 500 mu M of Cr.