Cobalt carbide-based theranostic agents for in vivo multimodal imaging guided photothermal therapy

Development of multifunctional theranostics is of great significance for cancer management. Herein, we develop polyethylene glycol (PEG) modified cobalt carbide nanoparticles (Co2C-PEG NPs) as cancer photothermal theranostic agents for multimodal imaging and photothermal therapy (PTT). Co2C NPs are synthesized by a high-temperature thermal decomposition method. Afterwards, the morphology, photothermal effect, multimodal imaging capacities, biocompatibility, and PTT efficacy of Co2C-PEG NPs are carefully investigated. The as-prepared Co2C-PEG NPs exhibit high photothermal conversion efficiency (PCE, η = 35.7%) and good photostability. Through photoacoustic (PA), magnetic resonance (MR), and photothermal (PT) tri-modal imaging, in vivo pharmacokinetics and tumor temperature elevation could be monitored during the PTT process. Meanwhile, the Co2C-PEG NPs also show good PTT efficacy both in vitro and in vivo. Our findings suggest that Co2C-PEG NPs are effective for cancer photothermal theranostics.