The manufactured modern medicine requires the development of miniaturized devices that can access hard-to-reach areas in the human body to complete therapeutic drug delivery or surgical procedures in less invasive and more effective manners. In this talk, I will discuss the challenges associated with operation of untethered small scale mobile soft robots with an important result in the development of miniaturized and mechanized tools that can be used to biopsy tissue and delivery drugs. Further, I will demonstrate highly sensitive and selective shape change in hydrogels that can be induced by specific DNA molecules by successive extension of crosslinks. Finally, I will discuss the design, fabrication, control, and applications of untethered mobile soft robots using remote magnetic fields in enclosed spaces.