Hybridization chain reaction-based DNA nanoframeworks for biosensing and therapeutic applications.

Artificial DNA nanostructures, with their sequence programmability, precise molecular recognition and tunable stimuli responsiveness, bridge material chemistry and biomedicine. Here we detail the design and construction of hybridization chain reaction (HCR)-based DNA nanoframeworks, a class of DNA nanostructures with programmable sequences and customizable functions. HCR is an efficient, enzyme-free amplification strategy that isothermally produces nicked double-stranded DNA with periodically repeated modules via the assembly of two DNA hairpins, triggered by a DNA initiator. In contrast to other available assembly methods for the synthesis of DNA nanostructures, such as tile-mediated assembly, DNA origami and rolling circle amplification, the HCR method offers improved stability and efficiency under mild conditions, without reliance on enzymatic activity. The procedure uses radical polymerization to integrate DNA initiator into nanoframeworks, with overhangs complementary to functional sequences - termed linkers -which are amplified and incorporated through HCR. The linkers enable the incorporation of functional nucleic acid sequences. The HCR-based DNA nanoframeworks facilitate the loading capability of the delivered molecules, showing notable therapeutic efficacy and biosensing sensitivity. Preparation time for HCR-based DNA nanoframeworks ranges from 30 h to 45 h, depending on the payload.