A DNA molecule is a genetic material composed of a double helix. Inspired by its unique characteristics, scientists have exploited DNA strands for engineering nanostructures. The development of DNA origami, which has enabled the customized production of DNA nanostructures, has been of crucial significance. Ever since, various DNA nanostructures have been proposed, promising the effective treatment of diverse diseases. In particular, we introduce the key strategies and technological advances of a range of DNA nanostructures, including DNA-based drug delivery systems and DNA nanorobots.