Feel the attraction of zwitterionic Janus Particles
Date:
April 13, 2022
Source:
Institute of Industrial Science, The University of Tokyo
Summary:
Researchers have created a more accurate computer simulation of
double- faced nanoparticles that form self-assembled structures
based on electrostatic attraction. By including temporary charge
fluctuations, compact clusters are shown to be a possible outcome,
which may lead to new smart nanomaterials.
FULL STORY ========================================================================== Researchers from The Research Center for Advanced Science and Technology
and The Institute of Industrial Science at The University of Tokyo used
a new computer simulation to model the electrostatic self-organization
of zwitterionic nanoparticles, which are useful for drug delivery. They
found that including transient charge fluctuations greatly increased the accuracy, which may help lead to the development of new self-assembling
smart nanomaterials.
==========================================================================
In ancient Roman mythology, Janus was the god of both beginnings and
endings.
His dual nature was often reflected in his depiction with two faces. He
also lends his name to so-called Janus particles, which are nanoparticles
that contain two or more distinct physical or chemical properties on
their surface.
One promising "two-faced" solution uses zwitterionic particles, which
are spheres with a positively charged side and a negatively charged side.
Researchers hope to create self-organizing structures, which can be
activated by changes in a solution's salt concentration or pH. However,
this kind of "bottom-up" engineering requires more accurate computer simulations to implement.
Now, a team of researchers from The Research Center for Advanced
Science and Technology and The Institute of Industrial Science at The University of Tokyo have created a new computer model that incorporates transient fluctuations in the change distributions on the surface of
the particles that can give rise to a wider variety of structures,
compared with current software. "Simulating the dynamic dissociation
or association of ionization groups is inherently more challenging, and
must be iterated repeatedly until self-consistent results are obtained,"
first author Jiaxing Yuan says.
The researchers showed that the previous method of assuming each of the particles carries a constant charge can give inaccurate results. To
simulate the possible transition to compact clusters, instead of
exclusively producing elongated strands, the computer needed to include short-lived fluctuations in surface charge. These differences are
particularly noticeable at low salt concentration and high electrostatic coupling strength.
In living organisms, proteins fold into very specific shapes based
in large part on the attraction between the positively and negatively
charged regions.
In the future, artificially designed particles may be able to
self-assemble when triggered by a change in conditions. "With zwitterionic particles, we hope to create functional materials with tunable properties, similar to the self- organization of charged proteins," senior author
Hajime Tanaka says.
========================================================================== Story Source: Materials provided by Institute_of_Industrial_Science,_The_University_of_Tokyo.
Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. Jiaxing Yuan, Kyohei Takae, Hajime Tanaka. Impact of Charge
Regulation on
Self-Assembly of Zwitterionic Nanoparticles. Physical Review
Letters, 2022; 128 (15) DOI: 10.1103/PhysRevLett.128.158001 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/04/220413090957.htm
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