Al-Rho particles remain in brain and may induce inflammation. a) Al-Rho nanomaterial detected in brain by rhodamine fluorescence (upper row and emission spectrum at 560 nm) remains associated with Al as assessed by Morin stain (middle row and emission spectrum at 520 nm); b) Al-Rho nanomaterial detected in the brain by PIXE. Al coating colocalizing with Gd core assesses the integrity of Al-Rho nanohybrid after translocation; c) In mice with i.m. co-injection of Al-Rho and rCCL-2, particle incorporation into neural cells was associated with immunohistochemical expression of IL1beta; d) Stereotactic injection of Al-Rho into the striatum was associated with no translocation to cervical LNs (CLN) at d4, contrasting with conspicuous translocation to popliteal LNs (PLN) observed when the same particle amount was injected in TA muscle; e) Stereotactic injection of Al-Rho into the striatum, compared to similar injection into muscle, was associated with very little translocation to spleen at both d4 and d21. (histograms: n = 3 per group, mean ± SD, * P <0.05, ** P <0.01, *** P <0.005; bar in c: 10 μm). Al(OH)3 rhodamine nanohybrid; d, day; LN, lymph nodes; n, number; PIXE, particle induced X-ray emission;TA, tibialis anterior.