Multifunctional Nanoprobe for MRI/Optical Dual‐Modality Imaging and Radical Scavenging

The development of novel nanomaterials for the diagnosis and/or treatment of human diseases has become an important issue. In this work, a multifunctional theranostic agent was designed by covalently binding hydroxyl‐ and amino‐bearing C 60 derivatives (C 60 O ∼10 (OH) ∼16 (NH 2 ) ∼6 (NO 2 ) ∼6 ⋅ 24 H 2 O) with gadolinium diethylenetriaminepentaacetic acid (Gd‐DTPA) to yield C 60 O ∼10 (OH) ∼16 (NH 2 ) ∼6 (NO 2 ) ∼6 ⋅ 24 H 2 O/(Gd‐DTPA) 3 ( DF 1 Gd 3 ). The obtained DF 1 Gd 3 shows more than fourfold contrast improvement over commercial Gd‐DTPA along with multiwavelength fluorescent emission for dual‐modality diagnosis. An inner‐ear magnetic resonance imaging (MRI) study was designed as a model of biological barriers, including the blood/brain barrier (BBB) for DF 1 Gd 3 to investigate its in vivo behavior. This revealed that the fabricated contrast agent dramatically increases the local contrast but can not cross the middle ear/inner ear barrier and endolymph/perilymph barrier in the inner ear, and thus it is also BBB‐prohibited in normal individuals. In vivo biodistribution studies suggested that 1)  DF 1 Gd 3 could circulate in vessels for a relatively long time and is mainly eliminated through liver and kidney, 2)  DF 1 Gd 3 may potentially function as a liver‐specific MRI contrast agent. Interestingly, DF 1 Gd 3 also shows an excellent quenching effect on hydroxyl radicals, as revealed by the DMPO spin trap/ESR method. The combination of enhanced MRI/FL imaging and local treatment of lesions is unique to DF 1 Gd 3 and potentiates the medical paradigm of “detect and treat/prevent” in combating human diseases related to reactive oxygen.