Strategy of pH induced reversible assemble of DNA wrapped SWCNTs. The mixture of Two SWCNT-DNA conjugates (SWCNT-G4 and SWCNT-C4) formed 3D aggregates at pH 8.0 through hybridization of G4 and C4. While the pH of buffer solution was adjusted to 5.0, G4 and C4 are formed and SWCNTs were dispersed. This assembly and disassembly process was reversible by adjusting the pH. Sequence of C4 DNA:(GT)20 –TTT TTT TTT TCC CAA TCC CAA TCC CAA TCC C. Sequence of G4 DNA: (GT)20 –TTT TTT TTT TGT GAT TGT GAT TGT GAT TGT G.