Fig. 2. The investigation of biobehavior in vivo (n = 4 for each group): blood circulation (a) and urinary excretion (b) of SPNS-PEG and Pd@Au-PEG; biodistribution of SPNS-PEG (c) and Pd@Au-PEG (d) in rats with the orthotopic liver tumor model. Asterisks suggest statistically significant differences (*P < 0.05, **P < 0.01, and ***P < 0.001).