The groups of Baoquan DING and colleagues at the National Center for Nanoscience and Technology (NCNST) in Beijing and of Hao YAN at Arizona State University have constructed DNA origami decorated with a DNA aptamer which specifically binds to nucleolin, a protein expressed on tumor-associated endothelial cells. The DNA origami contains thrombin which coagulates blood, thus inhibiting blood supply. When such vectors were i.v. injected to tumor-bearing mice, they were shown aggregate within 1 hour at the tumor, generated tumor tissue damage within 24 hours. Most of the nanorobots were cleared and degraded from the mouse body after 24 hours. By two days, there was evidence of advanced thrombosis, and after 3 days, thrombi in all tumor vessels were observed. in a melanoma mouse model, 3 out of 8 mice receiving the nanorobot therapy showed complete regression of the tumors. The median survival time more than doubled, extending from 20.5 to 45 days. The nanorobot proved to be safe and immunologically inert for use in normal mice and in mini pigs, showing no detectable changes in normal blood coagulation or cell morphology. There was no evidence of the nanorobots spreading into the brain (exclusion of stroke risks).
CAS news release, February 13, 2018