DNA Origami-enabled Nanofabrication And Its Application In Message Encryption

DNA origami-enabled nanofabrication can be used to organize nanoparticles or molecules like nucleic acids,proteins,quantum dots et al.into well-defined order,which has been extensively exploited in fields including nano-photonics,bio-imaging,catalysis and drug delivery.DNA origami is typically prepared by co-anneal of a scaffold strand with about 7000 nucleotides and over 2000 short staple stands.The high density of crossovers inside DNA origami brings it decent rigidity.Besides,every staple strand can be used individually as a pixel,which provides excellent addressability to DNA origami.A high concentration of salt(typically 12.5 mM or higher c(Mg²⁺))is essential for stable preservation of DNA origami.However,such a harsh condition is unavailable in physiological or other environments.What's worse,high concentrations of salt render the nanoparticles susceptible to aggregation.To overcome the problem,we transferred the DNA patterns concerning nanofabrication from DNA origami to gold nanoparticles?AuN Ps?and then conducted a template-free self-assembly of complicated nanostructures with the AuNP dictating the geometry.Besides,we developed a unique cryptosystem with DNA origami self-assembly due to the abundent information on DNA origami.The cryptosystem based on nanofabrication on DNA origami is highly secure and informative.At last,for the limitations on the geomerey and components of metal nanoparticles,we used DNA origami as the template to guide the synthesis of asymmetric metal nanoparticles with controllable shapes.Control over the components of metal nanoparticles will be further explored.Our work can be divided into four sections:1.Firstly,AuNPs were immobilized on DNA origami for assembly of a chiral gold pyramid with template.Then we written DNA patterns on AuNPs through message transfer from DNA origami to AuNPs and constructed a template-free gold pyramid with similar chirality.In this way,DNA origami was no longer needed for maintenance of gold nanostructures,which greatly expanded their application range.Theoretically,any nanoobject which can be joint with DNA can be functionalized with this method for self-assembly of complicated structures without template.2.The AuNPs carrying the DNA from a DNA origami cannot only be used for construction of template-free structures,but also used for assembly of another DNA origami if the transferred DNA contains a staple sequence.We call this inherited assembly since the assembly features of the first DNA origami are inherited to the second one.In this assembly process,the donor of DNA is called parent DNA origami while the acceptor is referred to as child DNA origami which has the same AuNP decoration as the parent.The DNA on the AuNPs acts as "gene" to rule the process.3.We further developed a new method for nanofabrication on DNA origami based on the self-assembly of DNA origami and turned it into an encrypted message transfer strategy.We encoded the message into a pattern and divided it into segments along the scaffold.A staple library key is necessary for folding of DNA origami to organize the segments and an indicator was then essential for uncovering the pattern.Finally decoding key was needed for reading plaintext.Other security strategies such as stitching keys and captchas were also involved.Multiple protection was provided in the process,which made it superior to existing chemical or biological methods.4.Finally,we synthesized shape-controlled nanoparticles by metallization with the single-strand DNA patterns on DNA origami as the template.It's rather difficult to achieve exquisite control over three-dimensional shapes,especially sophisticated and asymmetric shapes of nanoparticles with currently available methods.We arranged single-strand DNA patterns on DNA origami and conducted a metallization process in solution.The growth of metal nanoparticles was directed by the single-strand DNA patterns,which indicated that the geometry of the nanoparticles could be controlled simply through rearrangement of the single-strand DNA patterns.Since the patterns instead of DNA origami itself were used as template for metallization,the geometry of metal nanoparticles is not restricted by the available shapes of DNA origami.Even hollow structures can be fabricated with this method.What's more,stepwise growth of different metals could be achieved by successive opening of DNA hairpins.