Liu Wei, Yin Shengyan, Hu Yingcai, Deng Ting, Li Jishan
State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Institute of Applied Chemistry, School of Science, Central South University of Forestry and Technology, Changsha 410004, P. R. China.
Anal Chem. 2021 Oct 26;93(42):14223-14230. doi: 10.1021/acs.analchem.1c03128. Epub 2021 Oct 14.
Ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) are a novel T1 contrast agent with good biocompatibility and switchable imaging signal that have not been widely applied for magnetic resonance imaging (MRI) because it is difficult to induce their relatively close ideal agglomeration. Here, by combining the microemulsion method with the biomineralization principle, a pH-responsive T2-T1 switchable MRI nanoprobe was constructed via the microemulsion-confined biomineralization of PEGylated USPIONs (PEG-USPIONs). The size of the formed CaCO-coated PEG-USPION conjugates (PEG-USPIONs@CaCO nanoprobe) was uniform and controllable, and the preparation method was simple. The PEG-USPIONs inside the nanoconjugates agglomerate more tightly, and the T1-MRI signal of the nanoprobe is converted to the T2-MRI signal. When exposed to the acidic environment of the tumor tissue or internal organelles, the CaCO-coating of the nanoprobes is dissolved, and free PEG-USPIONs are released, thus realizing the T1-weighted imaging of the tumors. The suitability of the PEG-USPIONs@CaCO nanoprobe for tumor MRI detection was successfully demonstrated using a mouse model bearing a subcutaneous 4T1 xenograft.
超小超顺磁性氧化铁纳米颗粒（USPIONs）是一种新型的T1造影剂，具有良好的生物相容性和可切换的成像信号，但由于难以诱导其形成相对紧密的理想团聚，尚未广泛应用于磁共振成像（MRI）。在此，通过将微乳液法与生物矿化原理相结合，通过聚乙二醇化USPIONs（PEG-USPIONs）的微乳液受限生物矿化构建了一种pH响应型T2-T1可切换MRI纳米探针。形成的碳酸钙包覆的PEG-USPION缀合物（PEG-USPIONs@CaCO纳米探针）尺寸均匀且可控，制备方法简单。纳米缀合物内部的PEG-USPIONs团聚更紧密，纳米探针的T1-MRI信号转换为T2-MRI信号。当暴露于肿瘤组织或内部细胞器的酸性环境中时，纳米探针的碳酸钙涂层溶解，释放出游离的PEG-USPIONs，从而实现肿瘤的T1加权成像。使用携带皮下4T1异种移植瘤的小鼠模型成功证明了PEG-USPIONs@CaCO纳米探针对肿瘤MRI检测的适用性。
