Fig. 6: In vivo distribution of CAR neutrophil-delivered R-SiO₂-TPZ nanoparticles (NPs).

a Schematic of intravenously administered Cy5-labeled CAR neutrophil@R-SiO₂ NPs and R-SiO₂ NPs for in vivo cell tracking study. 5 × 10⁵ luciferase (Luci)-expressing U87MG cells were stereotactically implanted into the right forebrain of NRG mice. After 4 days, mice were intravenously treated with PBS, 5 × 10⁶ Cy5-labeled CAR neutrophil@R-SiO₂ NPs and R-SiO₂ NPs. b Time-dependent biodistribution of Cy5+ neutrophils in whole body, brain, and other organs was determined and quantified by fluorescence imaging at the indicated hours. c Biodistribution of CAR neutrophil@R-SiO₂ NPs and R-SiO₂ NPs in mice at 24 h post-injection was analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES) based on Si element, and data was expressed as the percentage of injected dose per gram of tissue (%ID/g). n = 5 biologically independent samples. Data are represented as mean ± SD. Source data are provided as a Source Data file. d Representative fluorescence images of CD45 and SiO₂ in the indicated glioblastoma xenografts isolated from tumor-bearing mice were shown. Scale bars, 100 μm. Biological triplicates were performed independently.