A Network of Networks to Reproduce the Electrical Features of an Aptamer-ligand Complex : What an Electrical Network Tells about Affinity

The increasing interest in the production and selection of aptamers for therapeutic and diagnostic applications yields many studies in recent years. Most of them investigated the production techniques, usually performed in vitro, but also the possibility of an in silico selection. Due to their specific ability of target-inhibition, some aptamers are under clinical trials, and some other were just patented by several pharmaceutical companies. However, the mechanism of aptamer-ligand formation is not completely understood. In this paper we explore the possibility to describe some topological and electrical features of the aptamer TBA alone and complexed with thrombin, its specific ligand, by using a network consisting of two different networks. The results are quite intriguing, confirming some conjectures about the different role of two cations, i.e. Na+ and K+, in stabilizing the compound. Furthermore, this study suggests the use of resistance measurements to discriminate among different affinities.