Figure 3.

Structures of cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides (ODNs) consisting of entirely phosphodiester backbone. (A) Sequence and structure of CpG ODN with a dumbbell-like structure: the CpG ODN with a dumbbell-like structure has 30 nucleotides in both loops that contain three CpG dinucleotide motifs.^a (B) Structure of dendrimer-like DNA: Y-shaped DNA consists of three single-stranded DNA with 30 nucleotides containing CpG dinucleotide motifs; G1, G2, and G3 dendrimer-like structures were synthesized by ligation of Y-shaped DNA; the sizes of CpG ODNs with G1, G2, and G3 dendrimer-like structures were about 12, 20, and 36 nm, respectively.^b (C) Assembly of CpG bearing DNA tetrahedral nanostructure: the core tetrahedral nanostructure consists of assembly with four 55-mer ODNs. The CpG motif is linked to each ODN via a 7-mer oligothyamine spacer.^c

^aReproduced with permission from Schmidt et al;^{52 b}reproduced with permission from Rattanakiat et al³⁰; ^creproduced with permission from Li et al.⁵⁵