Proceedings

EPJ E - Electric charge disorder: A key to biological order?

Strong attraction that arises between biological objects with random patches of electric charge on an otherwise neutral surface may partly explain pattern recognition in biology.

Theoretical physicist Ali Naji from the IPM in Tehran and the University of Cambridge, UK, and his colleagues have shown how small random patches of disordered, frozen electric charges can make a difference when they are scattered on surfaces that are overall neutral. These charges induce a twisting force that is strong enough to be felt as far as nanometers or even micrometers away. These results, just published in EPJE, could help to understand phenomena that occurr on surfaces such as those of large biological molecules.

To measure the strength of the twist that acts on a randomly charged surface, the authors used a sphere which was mounted like a spinning top next to a randomly charged flat substrate. Because small amounts of positive and negative charges were spread in a disordered mosaic throughout both surfaces, they induced transient attractive or repulsive twisting forces. This was regardless of the surfaces’ overall electrical neutrality, thus making the sphere spin. Using statistical averaging methods, the authors studied the fluctuations of these forces.

The authors found that the twisting force, created by virtue of the disorder of surface charges, is expected to be much stronger and far-reaching than the remnant forces. The latter are always present, even in the absence of charge disorder, and are due to fluctuations at the atomic and molecular levels.

This could have implications for large randomly charged surfaces such as biological macromolecules, which may be exposed to strong electrostatic forces, inducing attraction and/or repulsion, even if they carry no overall net charge. For instance, this phenomenon could partly explain biological pattern recognition, such as lock and key phenomena. In that context, the twisting force could explain the attraction between biological macromolecules that lead to pre-alignment prior to their interaction.

Sample-to-sample torque fluctuations in a system of coaxial randomly charged surfaces.
A. Naji et al., Eur. Phys. J. E (2012) 35: 24, DOI 10.1140/epje/i2012-12024-y

In the last years, I contributed to organize different scientific events with the University of Messina and the Bonino-Puleio foundation and with the support of the INFN. In the most of cases, we decided to publish the proceedings in the EPJ Web of Conferences. The main reasons of this choice are: the cost of the publication is very competitive with respect the other publisher (important to justify the expense with the own administration), the quality of the services are excellent from different points of view: the publishing editor and Collaborators are kind to furnish very soon all information and to process all requests, they are able to publish the proceedings in very short time and with high quality. The journal provides also citation indexing via ISI Web of Knowledge and Scopus, very important for the visibility of the articles and the authors.

Giuseppe Mandaglio, University of Messina, Italy
Co-editor EPJ Web of Conferences vol. 142 (2017)

ISSN: 2100-014X (Electronic Edition)

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