Difference between revisions of "Circumsembly"

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if up to (n-1) paths between A & B are blocked by irreversible assembly errors, self-assembly can still proceed from A all the way to B.<br>
 
if up to (n-1) paths between A & B are blocked by irreversible assembly errors, self-assembly can still proceed from A all the way to B.<br>
 
In practice much less than (n-1) paths should ever be blocked and the wole product assembled.
 
In practice much less than (n-1) paths should ever be blocked and the wole product assembled.
Minus the few irreversible assembly errors which can be tolerated in a good design.
+
Minus the few irreversible assembly errors which can be tolerated in a good design.<br>
 +
{{wikitodo|add a sketch}}
  
 
== Relation to yield in the synthesis of chain molecules ==
 
== Relation to yield in the synthesis of chain molecules ==
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But a stiff rod made from several parallel sub-strands can circumvent irreversible errors.
 
But a stiff rod made from several parallel sub-strands can circumvent irreversible errors.
  
== Prerequisites ==
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== Prerequisites for circumsembly ==
  
 
* selfassembly at multiple spots simultaneously
 
* selfassembly at multiple spots simultaneously
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* sufficient stiffness of selfassemblies such that the same spot can be reached via multiple (at least two) pathways
 
* sufficient stiffness of selfassemblies such that the same spot can be reached via multiple (at least two) pathways
  
== Benefits ==
+
== Benefits of circumsembly ==
  
 
*  A much reduced dropoff in yield of product. <br>Especially for 2d and 3D structures where the number of paths for circumvention grows quadratically/cubically respectively.
 
*  A much reduced dropoff in yield of product. <br>Especially for 2d and 3D structures where the number of paths for circumvention grows quadratically/cubically respectively.

Revision as of 16:39, 13 May 2022

This article defines a novel term (that is hopefully sensibly chosen). The term is introduced to make a concept more concrete and understand its interrelationship with other topics related to atomically precise manufacturing. For details go to the page: Neologism.

Circumsembly (or redundant access self-assembly) is selfassembly where
different parts A and B of the product-to-self-assemble are reachable by n (n being at least two) possible pathways, such that
if up to (n-1) paths between A & B are blocked by irreversible assembly errors, self-assembly can still proceed from A all the way to B.
In practice much less than (n-1) paths should ever be blocked and the wole product assembled. Minus the few irreversible assembly errors which can be tolerated in a good design.
(wiki-TODO: add a sketch)

Relation to yield in the synthesis of chain molecules

artificial synthesis of chain molecules by iterative addition of monomers to the reactive end
suffers from exponential/geometric drop-off in yield.
With every added monomer a probability smaller one of failure is multiplied.

An artificial selfassembled rod of de-novo proteins can suffer the same.
But a stiff rod made from several parallel sub-strands can circumvent irreversible errors.

Prerequisites for circumsembly

  • selfassembly at multiple spots simultaneously
  • sideward assembly crossing sub-strands is possible
  • sufficient stiffness of selfassemblies such that the same spot can be reached via multiple (at least two) pathways

Benefits of circumsembly

  • A much reduced dropoff in yield of product.
    Especially for 2d and 3D structures where the number of paths for circumvention grows quadratically/cubically respectively.

The math for how the drop-off in yield is reduced exactly in not entirely nontrivial.
(wiki-TODO: check out the math more closely) Minimal problem:

  • Given A rod of n parallel rows of 2D-squares starting out empty adding to the right only.
  • Successive addition at the growth front – this needs to accounting for sideward additions – nontrivial
  • What is the average blocknumber till all paths are blocked

This is likely easy for n=2 analytically.
For bigger n this might be easiest answered with a simulation.

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