TLR9 and periodontitis: Based on the aforementioned correlation of cfDNA and periodontitis, and the participation of TLR9 activation in the periodontitis immune response10, we synthesized nanoparticulate cfDNA scavenger, namely G3@SeHANs by coating the cationic dendrimer PAMAM-G3 on the surface of SeHANs (Fig. 2a).