Gd-Layered Double Hydroxides for Magnetic Resonance Imaging and Curcumin Delivery for Ischemic Stroke

Abstract

Herein, layered double hydroxides (LDHs) with varying gadolinium (Gd) content are synthesized using coprecipitation method and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and magnetic resonance imaging. Gd_0.1-LDHs exhibit characteristic diffraction peaks of LDHs and consist of ≈100 nm nanosheets (measured using Nano Measurer software), with a chemical composition of Mg_0.73Al_0.25Gd_0.022(OH)₂(NO₃)_0.12(CO₃)_0.075·0.8H₂O. MRI results reveal the longitudinal relaxivity (r₁) of Gd_0.1-LDHs and Gd_0.5-LDHs is 2.52 and 0.84 mM⁻¹ S⁻¹, respectively, which can be attributed to magnetic coupling effects. Curcumin (CUR) is loaded on Gd_0.1-LDHs, forming Gd_0.1-LDHs/CUR with a loading capacity of 14%. The release of CUR is pH-sensitive and follows a pseudo-second-order model, controlled by a diffusion process, with intraparticle diffusion as the rate-limiting step. Furthermore, the cytotoxicity of Gd_0.1-LDHs/CUR is evaluated using PC12 cells, the cell viability exceeds 100% even at a high concentration of 100 μg mL⁻¹, confirming its excellent biocompatibility. Additionally, in vitro experiments show that Gd_0.1-LDHs/CUR improves the cell viability of PC12 cells following oxygen and glucose deprivation from 75.3% to 88.3%, indicating its potential to alleviate cellular damage. This study presents a novel approach to developing nanoprobes for diagnosing and treating cerebral ischemia-reperfusion injury.