The possibility of engineering self-replicating nano-materials has emerged due to research into DNA (deoxyribonucleic acid), a self-replicating molecule whose component parts – nucleotides – have specific chemical interactions that allow for the design of self-assembled structures.
In biological systems, DNA replicates with the aid of proteins. A recent study conducted by Junghoon Kim, Junwye Lee, Shogo Hamada, Satoshi Murata, and Sung Ha Park of Sungkyunkwan University and Tohoku University led to the design of a controllable self-replicating system that does not require proteins.
The team demonstrated that nanoscale self-replication can occur using the thermodynamic properties of toehold-mediated strand displacement and self-assembly abilities of DNA motifs. Synthetic DNA T-motifs self-assembled into structures that enabled sequential reactions to occur, demonstrating the possibility of functionally programmable self-replicating nano-structures.
The team designed two DNA T-motifs – r1 and r2 – double-stranded DNA comprised of functional domains that were labelled alpha and beta, with “sticky” ends as connection points. In addition, they also designed an extension motif.
This allowed the DNA structures to form ring structures that could replicate, based on having fertilised and unfertilised component states. These structures reacted to different agents, with parts that broke off assembling into an identical ring structure. This process continues through two different replication pathways, with one growing exponentially and the other pathway growing according to a Fibonacci number sequence. … (read more)