Dual-modality contrast agents for T₁-weighted magnetic resonance imaging (MRI) and photoacoustic imaging have attracted substantial attention as they combine the advantages of unlimited penetration depth and high sensitivity. However, most of the reported agents are Gd-based materials that exhibit nephrotoxicity, and few studies have focused on Fe-based materials owing to their lower relaxivity. This work describes the development of an ellagic acid (EA)–Fe nanoscale coordination polymer with high longitudinal relaxivity and strong near-infrared absorption for dual-modality T₁-weighted MRI and photoacoustic imaging. The longitudinal relaxivity (r₁) of the prepared EA-Fe@BSA nanoparticles was 2.54 mM⁻¹ s⁻¹, an increase of 185% compared with previously reported gallic acid-Fe nanoparticles. Furthermore, in vitro and in vivo experiments demonstrate that the EA-Fe@BSA NPs are an excellent T₁-weighted MRI and photoacoustic dual-modality contrast agent with the advantages of convenient synthesis and low toxicity, exhibiting great potential for clinical use in tumor imaging.

用于T ₁加权磁共振成像（MRI）和光声成像的双峰型造影剂由于结合了无限的穿透深度和高灵敏度的优势而备受关注。但是，大多数报道的试剂是具有肾毒性的Gd基材料，由于铁基材料的弛豫度较低，因此很少有研究集中在Fe基材料上。这项工作描述了鞣花酸（EA）-铁纳米级配位聚合物的开发，该聚合物具有高纵向弛豫性和强的近红外吸收能力，可用于双峰T ₁加权MRI和光声成像。制备的EA-Fe @ BSA纳米颗粒的纵向弛豫度（r ₁）为2.54 mM ^-1 s ^-1，与先前报道的没食子酸-Fe纳米颗粒相比增加了185％。此外，体外和体内实验表明，EA-Fe @ BSA NPs是一种出色的T ₁加权MRI和光声双峰造影剂，具有合成方便，毒性低的优点，在肿瘤的临床应用中具有很大的潜力。成像。