DOX-conjugated CQD-based nanosponges for tumor intracellular pH-triggered DOX release and imaging

Novel tumor nanotheranostics were designed by conjugating doxorubicin (DOX) onto the hydrazine-functionalized crosslinked carbon quantum dots (CQDs)/polyethylene glycol bisacrylate (PEGBA) (C-CQDPEGBA-Hy) nanosponges via an acid-labile imine bond for the tumor intracellular real-time imaging and pH-triggered DOX release. The proposed prodrug nanotheranostics with a DOX content of 14.57 % and a mean hydrodynamic diameter around 116 nm showed excellent pH-triggered drug release performance, with a cumulative release of 52.71 % in the simulated tumor intracellular microenvironment in 4 days, while a premature drug leakage of 7.09 % in the simulated normal physiological medium. Besides, the fluorescence could be recovered during the drug release, indicating the potential application for tumor intracellular real-time imaging.