DNA has been extensively studied for supramolecular self-assembly towards structural control at the nanometer scale. The essential concept is to construct well-defined structures by integration of stiff branched DNA motifs and predictable intermolecular interactions. DNA conformational changes provide means for introduction of nanomotions. Building on previous works, we have designed and assembled a various DNA nanomachines, and started to explore their potential applications. Our works contain four sections:

i)                    an autonomous DNA machine;

ii)                   a proton-fueled DNA machine;

iii)                 a pair of molecular gears;

iv)                 switching chemical reactions by a DNA machine.