Title: Photoinduced Superhydrophilicity of Gd-Doped TiO2 Ellipsoidal Nanoparticles Boosts T1 Contrast Enhancement for Magnetic Resonance Imaging

Authors: Kun Liu, Zhongyuan Cai, Xiaoqin Chi, Bilun Kang, Shengxiang Fu, Xiangjie Luo, Zhi-Wei Lin, Hua Ai*, Jinhao Gao*, and Hongyu Lin*

Abstract: The unsatisfactory performance of current gadolinium chelate based T₁ contrast agents (CAs) for magnetic resonance imaging (MRI) stimulates the search for better alternatives. Herein, we report a new strategy to substantially improve the capacity of nanoparticle-based T₁ CAs by exploiting the photoinduced superhydrophilic assistance (PISA) effect. As a proof of concept, we synthesized citrate-coated Gd-doped TiO₂ ellipsoidal nanoparticles (GdTi-SC NPs), whose r₁ increases significantly upon UV irradiation. The reduced water contact angle and the increased number of surface hydroxyl groups substantiate the existence of the PISA effect, which considerably promotes the efficiency of paramagnetic relaxation enhancement (PRE) and thus the imaging performance of GdTi-SC NPs. In vivo MRI of SD rats with GdTi-SC NPs further demonstrates that GdTi-SC NPs could serve as a high-performance CA for sensitive imaging of blood vessels and accurate diagnosis of vascular lesions, indicating the success of our strategy.

Full-Link: https://pubs.acs.org/doi/10.1021/acs.nanolett.1c04676