ROS-activated selective fluorescence imaging of cancer cells via the typical LDH-based nanozyme

The detection and treatment based on tumor microenvironment (TME) are essential in cancer therapy. Currently, nanomaterials with mimic-enzyme property have attracted tremendous interest and the regulation of the sensing and catalytical activity inside the living cells remains a challenge. Herein, a reactive oxygen species (ROS) driven nanozyme, with selective activated fluorescence imaging and multiple enzyme activity (including peroxidase, superoxide dismutase and catalase), was achieved via the confinement of CDs on the ultrathin CuAl-LDH (denoted as CDs/LDHzyme). This unique CDs/LDHzyme demonstrate H2O2-responsive turn-on fluorescence via the self-regulating electron transfer process between Cu2+ and CDs. Furthermore, generated Cu+ through this electron transfer process can be beneficial for the POD-like activity, resulting an outstanding catalytic efficiency with the maximum initial velocity (Vmax) as high as 2.002 × 10−7 M s−1, which is 229.9% higher than the natural peroxidase enzyme (Horseradish Peroxidase, HRP). Structure characterization and energy level calculation can further prove the mechanism of this self-regulating electron transfer process. These findings open an avenue to enable the utilization of nanozyme as a remedial nanoplatform to the selective fluorescence imaging and nanozyme-initiated chemodynamic therapy (NCDT).