Gadolinium doped red-emissive carbon dots as targeted theranostic agents for fluorescence and MR imaging guided cancer phototherapy

As a new type of fluorescent agents, carbon dots (CDs) have revealed great potential in biomedical imaging applications attributed to their unique optical properties and good biocompatibility. However, engineering a versatile CDs nanoplatform integrating multifunctional imaging and therapeutic functionalities has always been an intractable challenge in targeted cancer treatment based on carbon nanomaterials. Herein, a gadolinium-doped CD conjugated with AS1411 aptamers (AS1411-Gd-CD) was prepared via facile solvothermal approach for targeted fluorescence (FL)/MR imaging guided photothermal therapy (PTT). The synthesized AS1411-Gd-CDs exhibited uniform nanostructure, good biocompatibility, strong red-fluorescence emission, significant MR contrast and efficient photothermal conversion. Benefiting from these outstanding properties, the AS1411-Gd-CDs were successfully employed in tumor-specific FL/MR dual-modal imaging in vitro and in vivo. Furthermore, under the guidance of FL/MR imaging, the AS1411-Gd-CDs demonstrated significant tumor inhibition effect owing to the outstanding photothermal effect. Thus, this study provided a versatile CDs nanoplatform as a multifunctional theranostic agent for synergistic FL/MR imaging and PTT in cancer treatment.