Thermal driven selfassembly diffusion speed slowdown blockade
With increasingly larger structures/parts/building-blocks the diffusion speeds increasingly drop.
This eventually makes thermally driven selfassembly impractical.
So why not just keep adding small parts to big parts then?
The problem with that idea is that the space of potential binding site gets too large.
The places that newly added small parts need selectively bind to gets too numerous.
At some point there is no way around going for some workaround
which eventually involved positional assembly.
In the diagram the blockade occurs when going only to the right to where it states "too big to diffuse".
Complementary blockade
Attempting to go to the other side (the left side in the diagram) leads right away
into to the complementary blockade here on this wiki called "positional assembly redundancy blockade"
which is present in the context of the incremental path.
This complementary blockade is not present for the direct path context
but there the struggle of scaling up (convergent assembly)
is strictly beyond the very hard problem to first go to positional assembly stage 2 or 3 to the left,
unless eventually following a mixed path.
Thus this diagram makes limited sense for the pure direct path context.
Workarounds
- hierarchical selfassembly making all parts grow in size
- tether assisted assisted self assembly (also mechanosynelf assembly)
- nonthermal self assembly
- Positional assembly
Bottlenecks assumed to be already taken care of here
Note that this is all beyond more basic problems that
are here assumed to be already optimized so far possible / feasible.
One example in the case of structural DNA nanotechnology:
When going to too many free floating parts
(oglionucleotide staple strands, aka DNA bricks, acting like vocels filling a roughly cuboid 3D canvas)
then one starts incurring significant slowdown in self-assembly since
the parts have an increasingly hard time finding their respective (increasingly dilute) binding partners.
One approach to accelerate selfassembly is using a long templating strand. Incresing effective concentration. Assing some self folding to self finding.
Protenins have mostly pure self folding.