Adenosine triphosphate-responsive carbon dots nanoreactors for T1-weighted magnetic resonance imaging-guided tumor chemodynamic therapy

There are various strategies to conduct tumor microenvironment (TME) stimulus-responsive (e.g., acid, H2O2 or glutathione) nanoreactors for increasing the efficiency of chemodynamic therapy (CDT). Among these, the exploitation of adenosine triphosphate (ATP, another over-expressed biomarker in TME)-responsive nanoreactors for tumor CDT is still challenging. Herein, the ATP-responsive iron-doped CDs (FeCDs) were firstly prepared and then co-assembled with glucose oxidase (GOx) to obtain FeCDs/GOx liposomes as ATP-responsive nanoreactors. Under TME conditions, the nanoreactors initially released FeCDs and GOx. Subsequently, with the existence of ATP, iron ions were rapidly released from the FeCDs to trigger Fenton/Fenton-like reactions for generating <middle dot>OH. Meanwhile, the T1-weighted magnetic resonance imaging (MRI) was achieved due to the released iron ions. Moreover, the GOx converted endogenous glucose in tumor to gluconic acid and H2O2 to satisfy the requirement of <middle dot>OH generation. In vitro as well as in vivo experiments illustrated that the obtained ATP-responsive CD nanoreactors could be used as a versatile nanotheranostics for simultaneously T1-weighted MRI-guided tumor CDT. This work presents a new ATP-responsive nanoreactor with self-supplied H2O2 for multifunctional nanotheranostic applications.