Figure 7.

Evaluation of delayed cytotoxicity effects. Cell viability has been tested by FDA staining assay, in presence and absence of P3HT NPs (± P3HT NPs, 0.2 OD, panel lines A–D respectively), and in presence or absence of polymer photoexcitation (± light, panel lines A–D, respectively), at fixed time points after plating and NPs administration. At 1 DIV, the same illumination protocol used for ROS generation was applied to samples treated by light (CW LED light illumination, peak emission wavelength λ = 540 nm, closely matching the polymer absorption spectrum; photoexcitation density P = 95 mW/mm²; overall duration of the photoexcitation protocol, 2 min). Viable cells were then stained at fixed time points, namely 6, 24, 48, 72 h after the illumination protocol, corresponding to a maximum of 4 DIV (from left to right panels, respectively). Scale bar, 100 μm.