• Feel the attraction of zwitterionic Janu

    From ScienceDaily@1:317/3 to All on Wednesday, April 13, 2022 22:30:46
    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

    --- up 6 weeks, 2 days, 10 hours, 51 minutes
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)