Tumor metastasis to brain is the main clinical manifestation of patients with advanced breast cancer, leading to poor survival prognosis. In order to detect the early incidence of brain metastasis, it is urgent to develop hypersensitive contrast agents for multimode imaging. In this study, PEG-phospholipids coated, a phage play derived peptide, BRBP1 peptide modified ultra-small iron oxide nanoparticles were prepared for targeted NIRF and MR imaging of breast cancer brain metastasis. The nanoparticles showed 10 nm core-shell, high relaxivity values and photon emission efficiency in vitro. The nanoparticles offered a T2 contrast imaging effect and near-infrared fluorescent signal enhancement. Compared with control peptide modified nanoparticles, the MR/NIRF imaging signal of BRBP1-modified nanoparticles in tumor tissue was significantly enhanced, which should be induced by the targeting ability of BRBP1 peptide. These results indicated that BRBP1-SPIO@mPEG (DiR) nanoparticles could be applied as an effective targeted delivery system for diagnosis of breast cancer brain metastasis.

肿瘤向脑转移是晚期乳腺癌患者的主要临床表现，导致预后不良。为了检测脑转移的早期发生，迫切需要开发用于多模式成像的超敏造影剂。在这项研究中，制备了涂有PEG磷脂的噬菌体衍生肽，BRBP1肽修饰的超小氧化铁纳米颗粒，用于乳腺癌脑转移的靶向NIRF和MR成像。纳米粒子在体外显示出10 nm的核壳，高弛豫值和光子发射效率。纳米颗粒提供了T2对比成像效果和近红外荧光信号增强。与对照肽修饰的纳米粒子相比，BRBP1修饰的纳米粒子在肿瘤组织中的MR / NIRF成像信号显着增强，这应该由BRBP1肽的靶向能力诱导。这些结果表明BRBP1-SPIO @ mPEG（DiR）纳米粒子可作为诊断乳腺癌脑转移的有效靶向输送系统。