Self-organization of complex structures: A matter of time

Date:
January 19, 2022
Source:
Ludwig-Maximilians-Universita"t Mu"nchen
Summary:
Researchers have developed a new strategy for manufacturing
nanoscale structures in a time- and resource-efficient manner.



FULL STORY ==========================================================================
LMU researchers have developed a new strategy for manufacturing nanoscale structures in a time- and resource-efficient manner.


========================================================================== Macromolecules such as cellular structures or virus capsids can emerge
from small building blocks without external control to form complex
spatial structures. This self-organization is a central feature of
biological systems.

But such self-organized processes are also becoming increasingly
important for the building of complex nanoparticles in nanotechnological applications. In DNA origami, for instance, larger structures are created
out of individual bases.

But how can these reactions be optimized? This is the question that LMU physicist Prof. Erwin Frey and his team are investigating. The researchers
have now developed an approach based on the concept of time complexity,
which allows new strategies to be created for the more efficient
synthesizing of complex structures, as they report in the journal PNAS.

A concept from the computer sciences Time complexity originally describes problems from the field of informatics. It involves investigating how
the amount of time needed by an algorithm increases when there is more
data to process. When the volume of data doubles, for example, the time required could double, quadruple, or increase to an even higher power. In
the worst case, the running time of the algorithm increases so much that
a result can no longer be output within a reasonable timeframe.

"We applied this concept to self-organization," explains Frey. "Our
approach was: How does the time required to build large structures change
when the number of individual building blocks increases?" If we assume
-- analogously to the case in computing -- that the requisite period
of time increases by a very high power as the number of components
increases, this would practically render syntheses of large structures impossible. "As such, people want to develop methods in which the time
depends as little as possible on the number of components," explains Frey.

The LMU researchers have now carried out such time complexity analyses
using computer simulations and mathematical analysis and developed
a new method for manufacturing complex structures. Their theory shows
that different strategies for building complex molecules have completely different time complexities - - and thus also different efficiencies. Some methods are more, and others less, suitable for synthesizing complex
structures in nanotechnology. "Our time complexity analysis leads to a
simple but informative description of self- assembly processes in order
to precisely predict how the parameters of a system must be controlled
to achieve optimum efficiency," explains Florian Gartner, a member of
Frey's group and lead author of the paper.

The team demonstrated the practicability of the new approach using a
well-known example from the field of nanotechnology: The scientists
analyzed how to efficiently manufacture a highly symmetrical viral
envelope. Computer simulations showed that two different assembly
protocols led to high yields in a short window of time.

A new strategy for self-organization When carrying out such experiments
before now, scientists have relied on an experimentally complicated method
that involves modifying the bond strengths between individual building
blocks. "By contrast, our model is based exclusively on controlling the availability of the individual building blocks, thus offering a simpler
and more effective option for regulating artificial self-organization processes," explains Gartner. With regard to its time efficiency, the
new technique is comparable, and in some cases better, than established methods. "Most of all, this schema promises to be more versatile and
practical than conventional assembly strategies," reports the physicist.

"Our work presents a new conceptual approach to self-organization,
which we are convinced will be of great interest for physics,
chemistry, and biology," summarizes Frey. "In addition, it puts
forward concrete practical suggestions for new experimental
protocols in nanotechnology and synthetic and molecular biology." ========================================================================== Story Source: Materials provided by
Ludwig-Maximilians-Universita"t_Mu"nchen. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Florian M. Gartner, Isabella R. Graf, Erwin Frey. The time
complexity of
self-assembly. Proceedings of the National Academy of Sciences,
2022; 119 (4): e2116373119 DOI: 10.1073/pnas.2116373119 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220119121343.htm

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