Synthesis and In Vitro Characterization of Fe3+-Doped Layered Double Hydroxide Nanorings as a Potential Imageable Drug Delivery System

Highly dispersed Fe3+-doped layered double hydroxide (LDH-Fe) nanorings were obtained by a simple coprecipitation-acid etching approach. The morphology, structure, magnetic resonance imaging (MRI) performance in vitro, drug loading and releasing, Fe3+ leakage, and cytotoxicity of the as-prepared LDH-Fe nanorings were characterized. The LDH-Fe nanorings showed good water dispersity and a well-crystallized structure. The DLS average size of nanoparticles was measured to be 94.5 nm. Moreover, the MRI tests showed a favourable T1-weighted MRI performance of the LDH-Fe nanoring with r1 values of 0.54 and 1.68, and low r2/r1 ratios of 10.1 and 6.3, pre- and after calcination, respectively. The nanoparticles also showed high model drug (ibuprofen) loading capacities, low Fe3+ leakage, and negligible cytotoxicity. All these results demonstrate the potential of LDH-Fe nanorings as an imageable drug delivery system.