Dynamic Chemistry of Disulfide Terminated Oligonucleotides in Duplexes and Double‐Crossover Tiles

Abstract

Designed nanostructures formed by self-assembly of multiple DNA strands suffer from low stability at elevated temperature and under other denaturing conditions. Here, we propose a method for covalent coupling of DNA strands in such structures by the formation of disulfide bonds; this allows disassembly of the structure under reducing conditions. The dynamic chemistry of disulfides and thiols was applied to crosslink DNA strands with terminal disulfide modifications. The formation of disulfide-linked DNA duplexes consisting of three strands is demonstrated, as well as a more-complex DNA double-crossover tile. All the strands in the fully disulfide-linked structures are covalently and geometrically interlocked, and it is demonstrated that the structures are stable under heating and in the presence of denaturants. Such a reversible system can be exploited in applications where higher DNA stability is needed only temporarily, such as delivery of cargoes to cells by DNA nanostructures.

Base‐Sequence‐Independent Efficient Redox Switching of Self‐Assembled DNA Nanocages

“…Over the past three decades, dynamic DNA nanotechnology has attracted extensive interest due to its great potential in nanomachinery, smart drug delivery, and biocomputing . Various chemical and physical stimuli have been introduced to trigger a dynamic DNA system, including protons, heat, light, enzymes, metal ions, and redox agents . Among these studies, redox‐responsiveness has been widely pursued, owing to its physiological relevance, which might generate important biotechnical applications .…”

“…Various chemical and physical stimuli have been introduced to trigger a dynamic DNA system, including protons, heat, light, enzymes, metal ions, and redox agents . Among these studies, redox‐responsiveness has been widely pursued, owing to its physiological relevance, which might generate important biotechnical applications . However, only a few successes have been reported so far.…”

“…Disulfide crosslinking has exhibited great potential in drug delivery and controlled release due to its responsiveness to versatile in vivo redox environments . Recently, redox‐responsive DNA nanostructures were realized by synthetic incorporation of disulfide linkages in DNA strands . This strategy has an impressive generality that can be adapted to different DNA structures.…”

“…This strategy has an impressive generality that can be adapted to different DNA structures. However, covalent modification of a redox‐responsive unit into a regular DNA sequence would add extra synthetic efforts, along with significantly increased costs . Therefore, an intrinsically different method toward the facile, universal, and reversible control of dynamic DNA assemblies based on redox chemistry is greatly anticipated.…”

Sequence-programmable covalent bonding of designed DNA assemblies

“…Researchers have therefore sought for ways to expand the range of conditions under which designed DNA objects remain stable. Additional covalent bonds have been introduced in exemplary structures between correspondingly modified strand termini via chemical ( 48 , 49 ) or enzymatic ligation ( 50 ). DNA nanostructures may also be further stabilized by the addition of cofactors such as 8-methoxypsoralen ( 51 ) or oligolysine and oligolysine–polyethylene glycol (PEG) copolymers ( 52 , 53 ).…”