Rare-earth-based polymeric nanobubbles as tri-modal imaging contrast agent

Medical imaging plays an important role in providing sufficient guidance for disease diagnosis and treatment. Among them, multimodal contrast agents can combine with a variety of imaging technologies to obtain comprehensive information on the lesion. It is an important development direction of medical imaging for accurate diagnosis of most diseases. In this study, we have designed and prepared a novel nanocomposite (i.e. NaGdF4:Eu@PLGA NBs) by combining sulfur hexafluoride (SF6) loaded polylactic acid-co-glycolic acid (PLGA) nanobubbles (NBs) with NaGdF4:Eu nanoparticles (NPs), which is the first research work on the composite assembly of ultrasound contrast bubbles with rare earth nanomaterials. Results show that NaGdF4:Eu@PLGA NBs with a diameter of appropriately 220 nm had uniform size and good in vitro stability. Combined with PLGA NBs’ superior ultrasound (US) imaging characteristics and NaGdF4:Eu NPs’ excellent magnetic resonance imaging (MRI) and computed tomography (CT) imaging characteristics, NaGdF4:Eu@PLGA NBs have exhibited significant and long-term in vitro US imaging, MRI and CT tri-modal contrast enhancement capability. Taken together, NaGdF4:Eu@PLGA NBs have great potential to be utilized in biomedical applications of US/MRI/CT tri-modal imaging.