In vitro and in vivo biocompatibility assessment of Pd@insulin clusters. A Blood glucose variation after Pd@insulin/insulin once administration (n = 5, * represents the significant difference between each time point and initial in Pd@insulin group, # represents the significant difference between Pd@insulin and insulin at one time point). B Survival curve of mice after once administrated by Pd@insulin/insulin (n = 5). C Long term blood glucose variation during Pd@insulin daily administration for 6 days (n = 3). D Liver and E renal functions evaluation (n = 3–4). F Representative electrocardiographs of Pd@insulin-treated mice and normal (Ctrl) mice. G Depression and anxiety-like behavior tests of Pd@insulin-treated mice and normal mice (Ctrl) via TST, FST, and SPT (n = 9). Data are all shown as mean ± SD. Statistical analysis of (A) was performed by one-way ANOVA with a Tukey post hoc test, and C–E and G were performed by unpaired Student’s t-test.