Department of Chemistry, Organic Chemistry Section, Jadavpur University, Kolkata 700032, India.
Division of Medical Engineering, School of Medicine, The Jikei University, Tokyo 105-8461, Japan.
J Am Chem Soc. 2023 Sep 20;145(37):20451-20461. doi: 10.1021/jacs.3c06232. Epub 2023 Sep 11.
Integrating an NIR fluorescent probe with a magnetic resonance imaging (MRI) agent to harvest complementary imaging information is challenging. Here, we have designed water-soluble, biocompatible, noncytotoxic, bright-NIR-emitting, sugar-functionalized, mechanically interlocked molecules (MIMs)-capped superparamagnetic ultrasmall FeO NPs for targeted multimodal imaging. Dual-functional stoppers containing an unsymmetrical NIR squaraine dye interlocked within a macrocycle to construct multifunctional MIMs are developed with enhanced NIR fluorescence efficiency and durability. One of the stoppers of the axle is composed of a lipophilic cationic TPP functionality to target mitochondria, and the other stopper comprises a dopamine-containing catechol group to anchor at the surface of the synthesized FeO NPs. FeO NPs surface-coated with targeted NIR rotaxanes help to deliver ultrasmall magnetic NPs specifically inside the mitochondria. Two carbohydrate moieties are conjugated with the macrocycle of the rotaxane via click chemistry to improve the water solubility of MitoSQRot-(Carb-OH)-DOPA-FeO NPs. Water-soluble, rotaxane-capped FeO NPs are used for live-cell mitochondria-targeted NIR fluorescence confocal imaging, 3D and multicolor imaging in combination with -weighted MRI on a 9.4 T MR scanner with a high relaxation rate () of 180.7 mM s. Biocompatible, noncytotoxic, ultrabright NIR rotaxane-capped superparamagnetic ultrasmall monodisperse FeO NPs could be a promising agent for targeted multimodal imaging applications.
将近红外（NIR）荧光探针与磁共振成像（MRI）造影剂集成以获取互补的成像信息具有挑战性。在这里，我们设计了水溶性、生物相容性、非细胞毒性、高光致发光、糖功能化、机械互锁分子（MIM）封端的超顺磁超小 FeO NPs，用于靶向多模态成像。双功能止动器包含一个非对称的 NIR 方酸染料互锁在大环中，以构建多功能 MIM，具有增强的近红外荧光效率和耐久性。轴的一个止动器由亲脂性阳离子 TPP 官能团组成，以靶向线粒体，另一个止动器包含含有多巴胺的儿茶酚基团，以锚定在合成的 FeO NPs 表面。表面涂覆有靶向 NIR 轮烷的 FeO NPs 有助于将超小磁性 NPs 特异性递送至线粒体内部。两个碳水化合物部分通过点击化学与轮烷的大环连接，以提高 MitoSQRot-（Carb-OH）-DOPA-FeO NPs 的水溶性。水溶性、轮烷封端的 FeO NPs 用于活细胞线粒体靶向近红外荧光共聚焦成像、3D 和多色成像，并结合 9.4 T MR 扫描仪上的加权 MRI，弛豫率（）高达 180.7 mM s。生物相容、非细胞毒性、超高亮度 NIR 轮烷封端的超顺磁超小单分散 FeO NPs 可能是一种有前途的靶向多模态成像应用的造影剂。
