Molecular magnetic resonance imaging (mMRI) of biomarkers is essential for accurate cancer detection in precision medicine. However, the current clinically used contrast agents provide structural magnetic resonance imaging (sMRI) information only and rarely provide mMRI information. Here, a tumor-specific furin-catalyzed nanoprobe (NP) was reported for differential diagnosis of malignant breast cancers (BCs) in vivo. This NP with a compact structure of Fe₃O₄@Gd-DOTA NPs (FFG NPs) contains an “always-on” T₂-weighted MR signal provided by the magnetic Fe₃O₄ core and a furin-catalyzed enhanced T₁-weighted MR signal provided by the Gd-DOTA moiety. The FFG NPs were found to produce an activated T₁ signal in the presence of furin catalysis and an “always-on” T₂ signal, providing mMRI and sMRI information simultaneously. Ratiometric mMRI:sMRI intensity can be used for differential diagnosis of malignant BCs MDA-MB-231 and MCF-7, where the furin levels relatively differ. The proposed probe not only provides structural imaging but also enables real-time molecular differential visualization of BC through enzymatic activities of cancer tissues.

中文翻译：

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弗林蛋白酶催化增强磁共振成像探针用于恶性乳腺癌的鉴别诊断

生物标志物的分子磁共振成像 (mMRI) 对于精准医学中准确的癌症检测至关重要。然而，目前临床使用的造影剂仅提供结构磁共振成像（sMRI）信息，很少提供mMRI信息。在此，报道了一种肿瘤特异性弗林蛋白酶催化纳米探针（NP）用于体内恶性乳腺癌（BC）的鉴别诊断。该 NP 具有紧凑的 Fe ₃ O ₄ @Gd-DOTA NP (FFG NP)结构，包含由磁性 Fe ₃ O ₄核和弗林蛋白酶催化增强 T ₁提供的“始终开启”T ₂加权 MR 信号-Gd-DOTA 部分提供的加权 MR 信号。研究发现，FFG NP在弗林蛋白酶催化作用下会产生激活的 T _{1信号和“始终开启”的 T 2}信号，同时提供 mMRI 和 sMRI 信息。比率mMRI：sMRI强度可用于鉴别诊断恶性BC MDA-MB-231和MCF-7，其中弗林蛋白酶水平相对不同。所提出的探针不仅提供结构成像，还可以通过癌组织的酶活性实现 BC 的实时分子差异可视化。