Figure 7.

Co-challenge experiment with silica NP and TiO₂ NP sensitized to 2-deoxy urushiol. Mice were sensitized with 15% 2-deoxyurushiol in an acetone vehicle. The right ears were challenged with 15% 2-deoxyurushiol alone and the left ears were co-challenged with 15% 2-deoxyurushiol and (a) silica NP (20 nm) or (b) TiO₂ mixed in an acetone/olive oil vehicle. The silica NP inhibited the ear swelling response to 2-deoxyurushiol. Mean ± SEM, *p < 0.05, 2 Student’s tailed t-Test, paired with unequal variances, N = 3–4