DNA origami nanorobots selectively eliminate tumor cells while protecting normal tissue. Researchers from Sweden’s Karolinska Institutet engineered a DNA-based nanorobot capable of destroying cancer cells without substantially harming healthy surrounding tissue. This microscopic device transports a potent cytotoxic molecule that stays concealed until it reaches the acidic conditions typical of many solid tumors. Upon detecting the lower pH, the nanorobot uncovers its lethal payload and initiates targeted destruction of malignant cells. Laboratory tests confirmed that the weapon stays dormant at physiological pH yet activates strongly in the acidic milieu associated with tumors. In mouse models of breast cancer the active nanorobot curtailed tumor expansion by roughly 70 percent relative to an inert control version. Construction relies on DNA origami, a method that precisely folds DNA strands into nanoscale architectures programmed for defined functions. The integrated safety mechanism aims to minimize collateral injury to healthy cells, addressing a persistent limitation of conventional anticancer therapies. Still at an early developmental stage, the platform has not undergone human trials. Future work will examine performance in more complex cancer models and refine tumor-type specificity. Successful progression could enable a novel class of precision cancer treatments. ["Nanorobot with hidden weapon kills cancer cells." Karolinska Institutet]