Fig. 3.

NIR-enhanced reduction capability of active hydrogen released from PdH_0.2 nanocrystals. a, b Hydrogen release in stimulated body fluid (a) and in HeLa cells (b), which was detected using MB as an oxidative probe for active hydrogen. P values were calculated by two-tailed Student’s t-test (*P < 0.05). c, d The effect of PdH_0.2 nanocrystals on intracellular ROS levels in cancer (HeLa cells, c) and normal (HEK-293T cells, d) cell models in the presence and absence of NIR irradiation (n = 6). In a, the treatment of MB with the H₂-rich water was used as the blank control without PdH_0.2 and NIR irradiation. Mean value and error bar are defined as mean and s.d., respectively