Loading
What changed between revision 2 and revision 3, compared over the article's markdown source with its frontmatter — so a change to status, evidence or reversibility shows up as the edit it is.
Older · revision 2
Import
Re-import of content/dna-nanotechnology.md — the file changed after the initial import. Not an edit.
14.3 kB
Revision 2
Revision 3
lines 8–14 → 8–147 unchanged lines not shown
categories: ["nanomedicine", "genetics"]categories: ["nanomedicine", "genetics"]tags: ["nanomedicine", "dna origami", "self-assembly", "molecular machines", "drug delivery", "biosensing"]tags: ["nanomedicine", "dna origami", "self-assembly", "molecular machines", "drug delivery", "biosensing"]summary: "The use of DNA as a construction material rather than a carrier of genes, folding programmed sequences into nanoscale shapes, devices, and logic-gated containers."summary: "The use of DNA as a construction material rather than a carrier of genes, folding programmed sequences into nanoscale shapes, devices, and logic-gated containers."updated: "2026-08-23"updated: "2026-10-29"humanEvidence: "No DNA nanostructure has entered a human trial; the strongest results are logic-gated payload release on cultured human cells and thrombin-loaded tubes that slowed tumour growth in mice."humanEvidence: "No DNA nanostructure has entered a human trial; the strongest results are logic-gated payload release on cultured human cells and thrombin-loaded tubes that slowed tumour growth in mice."access: "Research use only: scaffolds and staple strands are ordinary laboratory reagents, and no DNA nanostructure is available as a medical product anywhere."access: "Research use only: scaffolds and staple strands are ordinary laboratory reagents, and no DNA nanostructure is available as a medical product anywhere."reversibility: "reversible"reversibility: "reversible"lines 21–27 → 21–276 unchanged lines not shown
"rows": [ "rows": [ { "label": "Founded by", "value": "Nadrian Seeman, 1982" }, { "label": "Founded by", "value": "Nadrian Seeman, 1982" }, { "label": "Key method", "value": "DNA origami (Rothemund, 2006)" }, { "label": "Key method", "value": "DNA origami (Rothemund, 2006)" }, { "label": "Feature resolution", "value": "About 3–6 nanometres" }, { "label": "Feature resolution", "value": "About 3-6 nanometres" }, { "label": "Typical scaffold", "value": "M13 phage genome, ~7,200 bases" }, { "label": "Typical scaffold", "value": "M13 phage genome, ~7,200 bases" }, { "label": "Assembly", "value": "Thermal annealing in one pot" }, { "label": "Assembly", "value": "Thermal annealing in one pot" }, { "label": "Medical use", "value": "Animal studies only" }, { "label": "Medical use", "value": "Animal studies only" },lines 35–49 → 35–497 unchanged lines not shown
## How it works## How it works The founding insight is that the double helix is not the only structure DNA can form. Branched junctions occur naturally during recombination, but they migrate. Nadrian Seeman proposed in 1982 that by designing sequences with no symmetry, a junction could be made immobile, and immobile junctions could be linked into a rigid lattice.[^seeman1982] That converts DNA from a linear molecule into a construction kit with a programmable connectivity.The field starts from the fact that DNA can form structures other than the double helix. Branched junctions occur naturally during recombination, but they migrate. Nadrian Seeman proposed in 1982 that a junction built from sequences with no symmetry could be made immobile, and that immobile junctions could be linked into a rigid lattice.[^seeman1982] The idea turns DNA from a linear molecule into a construction kit with programmable connectivity. DNA origami, introduced by Paul Rothemund in 2006, made the approach practical.[^rothemund2006] A single long scaffold strand — usually the genome of the M13 bacteriophage, around 7,200 bases — is folded into a target shape by roughly two hundred short synthetic "staple" strands, each designed to bind two or three distant regions of the scaffold and hold them together. Mixing scaffold and staples and annealing over a few hours yields the designed object in enormous copy number, with folding yields high enough that misassembled structures are usually the minor product; the excess staples are then removed by filtration or gel extraction. Extending the method into three dimensions produced honeycomb and square lattices, then DNA "bricks" that build shapes without a scaffold at all, then assemblies in the gigadalton range.DNA origami, introduced by Paul Rothemund in 2006, made the approach practical.[^rothemund2006] A single long scaffold strand, usually the genome of the M13 bacteriophage at around 7,200 bases, is folded into a target shape by roughly two hundred short synthetic "staple" strands, each designed to bind two or three distant regions of the scaffold and hold them together. Mixing scaffold and staples and annealing over a few hours yields the designed object in enormous copy number. Folding yields are high enough that misassembled structures are usually the minor product, and the excess staples are then removed by filtration or gel extraction. Extending the method into three dimensions produced honeycomb and square lattices, then DNA "bricks" that build shapes without a scaffold at all, then assemblies in the gigadalton range. The resolution is set by the helix: features are addressable at roughly 3 to 6 nanometres, and every position on the structure has a known sequence, so a chemical group, a fluorophore, a protein, or a nanoparticle can be attached at a chosen coordinate. That addressability is the field's real advantage over the self-assembling but unaddressable vesicles of [[lipid-nanoparticles]], and it is what distinguishes it from the mechanical construction proposed in [[molecular-assembler]].The helix sets the resolution. Features are addressable at roughly 3 to 6 nanometres, and every position on the structure has a known sequence, so a chemical group, a fluorophore, a protein, or a nanoparticle can be attached at a chosen coordinate. This addressability is the field's real advantage over the self-assembling but unaddressable vesicles of [[lipid-nanoparticles]], and it distinguishes the field from the mechanical construction proposed in [[molecular-assembler]]. ## Development history## Development history The field moved in two phases. Two decades of structural work established that designed sequences could be made to hold a shape at all, mostly on lattices and polyhedra assembled from strands of similar length. The second phase began when folding a long natural scaffold with cheap synthetic staples turned that into a one-pot procedure any molecular biology laboratory could run, after which the interesting question stopped being whether a shape could be built and became what to attach to it.The field moved in two phases. Two decades of structural work established that designed sequences could be made to hold a shape at all, mostly on lattices and polyhedra assembled from strands of similar length. The second phase began when folding a long natural scaffold with cheap synthetic staples turned that into a one-pot procedure any molecular biology laboratory could run. After that, the open question was no longer whether a shape could be built but what to attach to it. ```timeline```timeline[[lines 60–101 → 60–10110 unchanged lines not shown
## Devices and logic## Devices and logic Static shapes were the first product; dynamic ones followed. None of them swims: motion in DNA devices means a conformational change or a walker stepping along a track, not locomotion through tissue, which remains the province of the externally steered machines in [[microrobots-in-medicine]]. Toehold-mediated strand displacement, in which an incoming strand invades a partially paired duplex from a single-stranded overhang, gives a reliable primitive for state change. Chained together, displacement reactions implement logic gates and multi-layer circuits operating entirely in solution, with no enzymes and no external control. Bipedal DNA walkers move along tracks by the same chemistry.Static shapes were the first product, and dynamic ones followed. None of them swims. Motion in DNA devices means a conformational change or a walker stepping along a track; locomotion through tissue remains the province of the externally steered machines in [[microrobots-in-medicine]]. Toehold-mediated strand displacement, in which an incoming strand invades a partially paired duplex from a single-stranded overhang, gives a reliable primitive for state change. Chained together, displacement reactions implement logic gates and multi-layer circuits operating entirely in solution, with no enzymes and no external control. Bipedal DNA walkers move along tracks by the same chemistry. The medical application of this machinery is conditional release. In 2012 a Harvard group built an origami barrel held shut by two aptamer locks, each of which opens only on binding a specified cell-surface protein; the device carried antibody fragments and released them selectively onto target leukaemia cells in culture.[^douglas2012] The logic was genuinely AND-gated: both antigens had to be present.The medical application of this machinery is conditional release. In 2012 a Harvard group built an origami barrel held shut by two aptamer locks, each of which opens only on binding a specified cell-surface protein. The device carried antibody fragments and released them selectively onto target leukaemia cells in culture.[^douglas2012] The logic was genuinely AND-gated, since both antigens had to be present. The strongest in vivo result to date used a simpler trigger. Origami tubes were loaded with thrombin and closed with an aptamer that binds nucleolin, a protein displayed on tumour endothelium but not on normal vessels. Injected into tumour-bearing mice, the devices opened at the tumour vasculature, released their cargo, and induced local thrombosis, slowing tumour growth in several models.[^li2018] It remains the most cited demonstration that a programmable DNA device can produce a therapeutic effect in an animal.The strongest in vivo result to date used a simpler trigger. Origami tubes were loaded with thrombin and closed with an aptamer that binds nucleolin, a protein displayed on tumour endothelium but not on normal vessels. Injected into tumour-bearing mice, the devices opened at the tumour vasculature, released their cargo, and induced local thrombosis, slowing tumour growth in several models.[^li2018] It remains the most cited demonstration that a programmable DNA device can produce a therapeutic effect in an animal. > [!note] What "nanorobot" means here> [!note] What "nanorobot" means here> These devices contain no power source, no processor, and no means of locomotion. They circulate passively and change state when a specific molecule binds. Calling them robots is a convention of the field rather than a description of their capabilities, a distinction that matters when comparing them with the designs in [[medical-nanorobots]] — [[eric-drexler]]'s cell-repair machines and Freitas's [[respirocytes|respirocyte]] are specified with onboard sensing, computation, and actuation, none of which an origami device has.> These devices contain no power source, no processor, and no means of locomotion. They circulate passively and change state when a specific molecule binds. Calling them robots is a convention of the field rather than a description of their capabilities. The distinction matters when comparing them with the designs in [[medical-nanorobots]]: [[eric-drexler]]'s cell-repair machines and Freitas's [[respirocytes|respirocyte]] are specified with onboard sensing, computation, and actuation, none of which an origami device has. ## Limitations in the body## Limitations in the body DNA is a poor material for blood. Three problems dominate.DNA is a poor material for blood, for three main reasons. Structures assembled at 10 to 20 millimolar magnesium partially unfold at the roughly 1 millimolar free magnesium of extracellular fluid. Nucleases in serum degrade unprotected origami within hours. And unmethylated CpG motifs in bacterial-derived scaffold sequence are recognised by Toll-like receptor 9, provoking an innate immune response that is useful when the structure is meant to be a vaccine scaffold and unwelcome when it is meant to be a carrier.Structures assembled at 10 to 20 millimolar magnesium partially unfold at the roughly 1 millimolar free magnesium of extracellular fluid. Nucleases in serum degrade unprotected origami within hours. And Toll-like receptor 9 recognises unmethylated CpG motifs in bacterial-derived scaffold sequence, provoking an innate immune response that is useful when the structure is meant to be a vaccine scaffold and unwelcome when it is meant to be a carrier. Coatings mitigate the first two. Oligolysine conjugated to polyethylene glycol electrostatically wraps the structure, stabilising it at low salt and slowing nuclease attack by an order of magnitude or more.[^ponnuswamy2017] Lipid bilayer coatings and protein shells achieve similar effects. None of these has yet carried a DNA device through a human trial, whereas the two crude carriers it competes with — [[aav-vectors]] and lipid vesicles — have each delivered approved products.Coatings mitigate the first two. Oligolysine conjugated to polyethylene glycol electrostatically wraps the structure, stabilising it at low salt and slowing nuclease attack by an order of magnitude or more.[^ponnuswamy2017] Lipid bilayer coatings and protein shells achieve similar effects. None of these has yet carried a DNA device through a human trial, whereas the two crude carriers it competes with, [[aav-vectors]] and lipid vesicles, have each delivered approved products. Payload capacity is a further constraint. An origami barrel holds a handful of protein molecules; a liposome of comparable size holds thousands of small-molecule drugs. For most therapeutic purposes the cargo-to-carrier ratio is unfavourable, which is one reason the clinical successes of nanomedicine have gone to formulations rather than to structures, as described in [[targeted-drug-delivery]].Payload capacity is a further constraint. An origami barrel holds a handful of protein molecules, while a liposome of comparable size holds thousands of small-molecule drugs. For most therapeutic purposes the cargo-to-carrier ratio is unfavourable. That is one reason the clinical successes of nanomedicine have gone to formulations rather than to structures, as described in [[targeted-drug-delivery]]. Cost was a fourth constraint until recently. Synthetic staple strands are expensive at scale, and a route that produces both scaffold and staples biologically in bacteriophage-infected bacteria has reduced the price of bulk origami by orders of magnitude, moving gram-scale production from implausible to demonstrated. The same falling cost of writing DNA underpins [[synthetic-genomes]] and has made sequence screening at synthesis providers a standing item in [[dual-use-research]] policy.Cost was a fourth constraint until recently. Synthetic staple strands are expensive at scale, and a route that produces both scaffold and staples biologically in bacteriophage-infected bacteria has reduced the price of bulk origami by orders of magnitude, moving gram-scale production from implausible to demonstrated. The same falling cost of writing DNA underpins [[synthetic-genomes]] and has made sequence screening at synthesis providers a standing item in [[dual-use-research]] policy. ## Uses beyond therapy## Uses beyond therapy The field's most consistent value has been as a laboratory tool. Origami acts as a molecular breadboard: a rigid, addressable surface for placing molecules at defined distances. DNA-PAINT exploits transient strand binding to achieve super-resolution imaging below the diffraction limit. Origami rulers calibrate microscopes. Nanopore experiments use DNA structures as gates and adapters, connecting to the sensing methods described in [[nanoparticle-diagnostics]].The field has been most consistently useful as a laboratory tool. Origami acts as a molecular breadboard, a rigid, addressable surface for placing molecules at defined distances. DNA-PAINT exploits transient strand binding to achieve super-resolution imaging below the diffraction limit. Origami rulers calibrate microscopes. Nanopore experiments use DNA structures as gates and adapters, connecting to the sensing methods described in [[nanoparticle-diagnostics]]. Immunology has produced a distinctive application. Because antigen spacing on a surface strongly affects B-cell activation, origami scaffolds displaying antigens at controlled separations have been used to dissect that dependence and to design immunogens — a use of the technology as a precision instrument rather than as a delivery vehicle.[^veneziano2020]Immunology has produced a distinctive application. Because antigen spacing on a surface strongly affects B-cell activation, origami scaffolds displaying antigens at controlled separations have been used to dissect that dependence and to design immunogens. Here the technology is a precision instrument rather than a delivery vehicle.[^veneziano2020] DNA is also a storage medium, a line of work associated with [[george-church]] among others, and one that shares synthesis and sequencing infrastructure with the fabrication side of the field but little else.DNA is also a storage medium, a line of work associated with [[george-church]] among others, and one that shares synthesis and sequencing infrastructure with the fabrication side of the field but little else. ## Outlook## Outlook The obstacle to clinical translation is not design but pharmacology: an object made of nucleic acid must survive serum, avoid the liver, escape the endosome, and release cargo where intended, and the field has partial answers to each and a complete answer to none. The most likely first clinical entries are those where DNA's drawbacks matter least — vaccine and immunotherapy scaffolds, where immune recognition is the point, and topical or local applications, where circulation is not involved.The obstacle to clinical translation lies in pharmacology rather than design. An object made of nucleic acid must survive serum, avoid the liver, escape the endosome, and release cargo where intended, and the field has partial answers to each and a complete answer to none. The most likely first clinical entries are those where DNA's drawbacks matter least: vaccine and immunotherapy scaffolds, where immune recognition is the point, and topical or local applications, where circulation is not involved. > [!caution] The leading candidate is a vaccine, not a carrier> [!caution] The leading candidate is a vaccine, not a carrier> The furthest-advanced construct is DoriVac, a square origami sheet that spaces CpG adjuvant and antigen at controlled distances. In 2026 it matched the approved mRNA vaccines on antibody and T-cell responses in mice and activated dendritic cells in a human lymph-node-on-chip, which is as close to a person as any DNA nanostructure has been.[^zeng2026]> The furthest-advanced construct is DoriVac, a square origami sheet that spaces CpG adjuvant and antigen at controlled distances. In 2026 it matched the approved mRNA vaccines on antibody and T-cell responses in mice and activated dendritic cells in a human lymph-node-on-chip, which is as close to a person as any DNA nanostructure has been.[^zeng2026]> Its mechanism is the TLR9 recognition of bacterial CpG described above — the property that disqualifies origami as a circulating carrier. A vaccine that works because the immune system notices it therefore says nothing about whether a DNA device can cross a bloodstream intact, which only a first human pharmacokinetic study would establish.> Its mechanism is the TLR9 recognition of bacterial CpG described above, the same property that disqualifies origami as a circulating carrier. A vaccine that works because the immune system notices it therefore says nothing about whether a DNA device can cross a bloodstream intact, which only a first human pharmacokinetic study would establish. Whether the addressability advantage ever justifies the fragility is the open question. A structure that positions two proteins exactly seven nanometres apart can do things no liposome can. As of 2026 nobody has shown that this buys enough in a patient to outweigh a material that dissolves in blood, and the [[crispr-cas9]] era has meanwhile demonstrated how much can be achieved with delivery vehicles that have no internal architecture at all.Whether the addressability advantage ever justifies the fragility is the open question. A structure that positions two proteins exactly seven nanometres apart can do things no liposome can. As of 2026 nobody has shown that this buys enough in a patient to outweigh a material that dissolves in blood, and the [[crispr-cas9]] era has meanwhile demonstrated how much can be achieved with delivery vehicles that have no internal architecture at all. removed, struck through added, underlinedLine numbers count the serialised markdown of each revision, frontmatter included.
105 lines are the same in both revisions, and 51 of them are not shown. Neither revision here is necessarily the current article — read DNA nanotechnology for the text this wiki stands behind today.