A DNA tetrahedron–affibody–drug nanoparticle is a highly efficient tool to deliver doxorubicin (DOX) to HER2 overexpressing cancer cells specifically. It represents a highly efficacious agent for selectively inhibiting cancer cells which overexpress HER2 receptor.

A DNA tetrahedron having a single-strand DNA edge was used to detect a dengue virus RNA sequence. Novel tandem toehold-mediated displacement reactions (tTMDR) were developed to amplify the fluorescence signal from the DNA tetrahedron. Using an excess of the DNA tetrahedron each target RNA was recycled about 10³ times during the tTMDR process. This amplification process was used for the sensitive detection of dengue virus RNA in this study. As few as 6 copies of RNA per sample could be detected using a photon count technique with single molecule sensitivity.

Cisplatin is the most widely used anticancer drug, but its side effects limit the maximum systemic dose. To circumvent the side effects, a DNA tetrahedron–affibody nanoparticle was prepared by combination of a DNA chain with cisplatin via interstrand crosslinks or adducts. Each nanocarrier can bind ∼68 molecules of cisplatin. This cisplatin nanoparticle exhibited high selectivity and inhibition for breast cancer HER2 overexpressing cells BT474 and lower toxicity in MCF-7 cells with low HER2 expression. The nano-drug inhibited the growth of BT474 cells by 94.57% at 512 nM (containing 33.3 μM cisplatin), which was higher than that of cisplatin (82.9%, 33.3 μM).