FIGURE 4.

Time‐dependent cytotoxicity of taPIT suggested the efflux of free BPD. Following 22‐h incubation with 250 nM BPD equivalent PIC and washing, 60 J/cm² light dose was administered at multiple time points. The cytotoxicity of taPIT decreased as the post‐wash incubation time increased. taPIT did not kill the EGFR‐negative cell line CHO‐K1 when the light dose was administered after 2 h of post‐wash incubation (A), while it killed the EGFR‐positive cell line OVCAR5 even when the light dose was administered after 4.5 h of post‐wash incubation (B). Treatments were performed in quadruplicate. Results are mean ± standard deviation.