LAYERED DOUBLE HYDROXIDE-BASED MRI/CT DUAL MODAL CONTRASTING AGENT WITH HOMOGENEOUS PARTICLE SIZE

The development of nanoparticles incorporating Gd3+has attracted interest in the field of contrasting nanomedicine for magnetic resonance (MR) and computed tomography (CT). In order to achieve an effective contrasting performance, the amount and stability of Gd incorporated as well as particle-size control of the nanoparticles should be considered simultaneously. In the current study, Gd-diethylenetriaminepentaacetate(Gd-DTPA) was incorporated into layered double hydroxide (LDH) to meet the physicochemical properties required for MR-CT dual contrasting nanomedicine. Strategically, the particle size and nanometer incorporation of Gd-DTPA into LDH (GL-R hybrid) were controlled homogeneously using the reverse micelle method. X-ray diffraction showed that the hybrid obtained possessed a hydrotalcite phase. Dynamic light scattering and electron microscopic analyses showed that the hybrid had a controlled size of <200 nm with significant homogeneity. Fast Fourier-transform of transmission electron microscopy confirmed that the platelets of the GL-R hybrids were oriented randomly to form inter-particle space, enabling the Gd-DTPA moiety to be encapsulated stably. The encapsulation efficiency of Gd-DTPA was 20.8%, which was sufficiently high compared with other Gd-DTPA-incorporatedLDH. According to X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, Gd-DTPA incorporated in the hybrid preserved its structure intact. Its potential as a dual modal contrast agent was demonstrated by measuring the concentration-dependent Hounsfield unit and magnetic resonance relaxivity, which were determined to be 230 at 2 mg/mL and 5.8 in the range ~0.2–1 mM-Gd, respectively.