Fig. 5.

Representative H&E stained images of (a) vital organ small intestine section of BALB/c nude mice untreated and (b) after oral gavage with DCNP@PDA NPs at 7 days, respectively, and (c) major organs including heart, liver, spleen, lung, kidney, stomach, duodenum, large intestine, cecum and rectum collected from the untreated mice (Control) and NaYF₄:Yb³⁺,Er³⁺@NaYbF₄@NaYF₄:Nd³⁺ @PDA NPs perfused mice at 7 days. No obvious organ damage or lesion was observed for NaYF₄:Yb³⁺,Er³⁺@NaYbF₄@NaYF₄:Nd³⁺ @PDA NPs treated mice. Scale bar: 100 μm.