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.

中文翻译：

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Gd 掺杂 TiO2 椭球纳米粒子的光致超亲水性促进磁共振成像的 T1 对比度增强

目前用于磁共振成像 (MRI) 的基于钆螯合物的T _{1造影剂 (CA) 的性能不令人满意，这促使人们寻找更好的替代品。}在此，我们报告了一种新策略，通过利用光诱导超亲水辅助 (PISA) 效应来显着提高基于纳米颗粒的T _{1 CAs 的容量。}作为概念验证，我们合成了柠檬酸盐包覆的 Gd 掺杂 TiO ₂椭球纳米粒子 (GdTi-SC NPs)，其r ₁紫外线照射后显着增加。降低的水接触角和增加的表面羟基数量证实了 PISA 效应的存在，这大大提高了顺磁弛豫增强 (PRE) 的效率，从而提高了 GdTi-SC NPs 的成像性能。具有 GdTi-SC NPs 的 SD 大鼠的体内MRI 进一步证明 GdTi-SC NPs 可以作为一种高性能的 CA，用于血管的敏感成像和血管病变的准确诊断，表明我们的策略是成功的。