Surface charge accumulation of functionalized carbonized polymer dots selectively induces lysosomal membrane permeabilization of breast cancer cells

•CPDs-PP showed ratiometric red-green fluorescence switching in cancer cells.•CPDs-PP protonated and aggregated in lysosome of breast cancer cells.•CPDs-PP induced lysosomal membrane permeabilization in breast cancer cells.•Autophagic degradation in breast cancer cells was suppressed by CPDs-PP. Lysosomal membrane permeabilization (LMP) has become an attractive strategy in tumor therapy. However, non-specific cytotoxicity caused by LMP remains a challenge; whether lysosomal-dependent autophagy process affected by lysosomal damage is still unclear. Here, we provide a carbonized polymer dots (CPDs)-based lysosomal targeted nano-strategy that mediates specific cytotoxicity to breast cancer cells by inducing LMP and disruption of autophagy degradation. CPDs functionalized via covalent conjugation with PpIX modified cathepsin D (CTSD) specific substrate peptide (CPDs-PP) were designed to achieve the selectivity to breast cancer cells. The effects and underlying mechanism of CPDs-PP on lysosomal membrane integrity and autophagic flux were determined. CPDs-PP with pH-dependent protonation and CTSD-responsive surface positive charge accumulation property at specific pH were obtained. Conversion of CPDs-PP to CPDs-P and ratiometric green–red fluorescence switching were observed in breast cancer cells with high expression of CTSD. It has been confirmed that CPDs-PP induced LMP and autophagic flux blockage of breast cancer cells. Lysosomal lipid accumulation was demonstrated to be the potential mechanism. CPDs-PP-induced LMP exhibited selective cytotoxicity to adherent tumor cells and tumor spheres, which was furtherly enhanced by spatiotemporal controlled lysosomal specific photodamage. This strategy offers promise for utilization of lysosome-targeting nanocarriers for anti-cancer pro-drugs and drug delivery systems.