摘要Self-assembling carrier-free nanodrugs are attractive agents because they accumulate at tu-mor by an enhanced permeability and retention(EPR)effect without introduction of inactive substances,and some nanodrugs can alter the immune environment.We synthesized a peptidyl arginine deiminase 4(PAD4)molecular inhibitor,ZD-E-1M.It could self-assembled into nanodrug ZD-E-1.Using confocal laser scanning microscopy,we observed its cellular colocalization,PAD4 activity and neutrophil extra-cellular traps(NETs)formation.The populations of immune cells and expression of immune-related pro-teins were determined by single-cell mass cytometry.ZD-E-1 formed nanoflowers in an acidic environment,whereas it formed nanospheres at pH 7.4.Accumulation of ZD-E-1 at tumor was pH-responsive because of its pH-dependent differences in the size and shape.It could enter the nucleus and bind to PAD4 to prolong the intracellular retention time.In mice,ZD-E-1 inhibited tumor growth and metastasis by inhibiting PAD4 activity and NETs formation.Besides,ZD-E-1 could regulate the ratio of immune cells in LLC tumor-bearing mice.Immunosuppressive proteins like LAG3 were suppressed,while IFN-γ and TNF-α as stimulators of tumor immune response were upregulated.Overall,ZD-E-1 is a self-assembling carrier-free nanodrug that responds to pH,inhibits PAD4 activity,blocks neutrophil extracellular traps formation,and improves the tumor immune microenvironment.