Plasma‐Activated Saline Triggers Macrophage M1 Polarization by Inducing Tumor Cell Apoptosis

ABSTRACT Here, we investigated the effects of aqueous reactive oxygen species (ROS) in surface air plasma‐activated solution (PAS) on the bladder cancer cell line MB49 and their role in remodeling the polarization status of tumor‐associated macrophages (TAMs). The study reveals substantial ROS production by plasma within PAS. In vitro experiments showed that the PAS exhibited an activation time‐dependent and significant cytotoxic effect on MB49 cells. Further validation using a transwell coculture model demonstrated that pretreatment of MB49 cells with PAS promoted the polarization of RAW264.7 macrophages toward the antitumor M1 phenotype. Our study reveals the dual role of PAS in direct tumor killing and immune regulation.