(A) Using reconfigurable DNA tetrahedron to detect intracellular ATP in living cells (adapted from Pei et al. 91). (B) Probing the functionality of a DNA nanomachine in coelomocytes of C. elegans (adapted from Surana et al.123). (C) Overview of single-cell gene silencing assay (adapted from Toriello et al.129). (D) Oligonucleotides directing the synthesis of 3-dimensional multicellular structures (adapted from Gartner et al.132). (E) Synthetic DNA membrane channels (adapted from Langecker et al.134).