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New geometries: Researchers create new shapes of artificial microcompartments

Date:
December 12, 2012
Source:
Northwestern University
Summary:
Researchers have figured out how to mimic the different shapes of microcompartments found in nature. The findings could have implications in materials research, targeted drug delivery, and more.
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n nature, biological functions are often carried out in tiny protective shells known as microcompartments, structures that provide home to enzymes that convert carbon dioxide into energy in plant cells and to viruses that replicate once they enter the cell.

Most of these shells buckle into an icosahedron shape, forming 20 sides that allow for high interface with their surroundings. But some shells -- such as those found in the single-celled Archaea or simple, salt-loving organisms called halophiles -- break into triangles, squares, or non-symmetrical geometries. While these alternate geometries may seem simple, they can be incredibly useful in biology, where low symmetry can translate to higher functionality.

Researchers at Northwestern University have recently developed a method to recreate these shapes in artificial microcompartments created in the lab: by altering the acidity of their surroundings. The findings could lead to designed microreactors that mimic the functions of these cell containers or deliver therapeutic materials to cells at specific targeted locations.

"If you want to design a very clever capsule, you don't make a sphere. But perhaps you shouldn't make an icosahedron, either," said Monica Olvera de la Cruz, Lawyer Taylor Professor of Materials Science and Engineering, Chemistry, and (by courtesy) Chemical and Biological Engineering at Northwestern's McCormick School of Engineering and one of the paper's authors. "What we are beginning to realize is maybe these lower symmetries are smarter."

To create the new shell geometries, the researchers co-assembled oppositely charged lipids with variable degrees of ionization and externally modified the surrounding electrolyte. The resulting geometries include fully faceted regular and irregular polyhedral, such as square and triangular shapes, and mixed Janus-like vesicles with faceted and curved domains that resembled cellular shapes and shapes of halophilic organisms.

The research was conducted by three McCormick faculty members: Olvera de la Cruz, Lawyer Taylor Professor of Materials Science and Engineering, Professor of Chemistry, and (by courtesy) Chemical and Biological Engineering; Michael J. Bedzyk, professor of materials science and engineering and (by courtesy) physics and astronomy; and Samuel I. Stupp, Board of Trustees Professor of Materials Science and Engineering, Chemistry, and Medicine.

Other authors of the paper include lead co-authors Cheuk-Yui Leung, Liam C. Palmer, and Bao Fu Qiao; Sumit Kewalramani, Rastko Sknepnek, Christina J. Newcomb, and Megan A. Greenfield, all of Northwestern; and Graziano Vernizzi of Siena College.


Story Source:

The above post is reprinted from materials provided by Northwestern University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Cheuk-Yui Leung, Liam C. Palmer, Bao Fu Qiao, Sumit Kewalramani, Rastko Sknepnek, Christina J. Newcomb, Megan A. Greenfield, Graziano Vernizzi, Samuel I. Stupp, Michael J. Bedzyk, Monica Olvera de la Cruz. Molecular Crystallization Controlled by pH Regulates Mesoscopic Membrane Morphology. ACS Nano, 2012; 121203090056009 DOI: 10.1021/nn304321w

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Northwestern University. "New geometries: Researchers create new shapes of artificial microcompartments." ScienceDaily. ScienceDaily, 12 December 2012. <www.sciencedaily.com/releases/2012/12/121212130903.htm>.
Northwestern University. (2012, December 12). New geometries: Researchers create new shapes of artificial microcompartments. ScienceDaily. Retrieved September 4, 2015 from www.sciencedaily.com/releases/2012/12/121212130903.htm
Northwestern University. "New geometries: Researchers create new shapes of artificial microcompartments." ScienceDaily. www.sciencedaily.com/releases/2012/12/121212130903.htm (accessed September 4, 2015).

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