Electrical Characterization of Actin Filaments and Gold Nanoparticles Functionalized Microtubules

Nowadays microtubules and actin filaments have aroused great interest due to their structural support abilities and their intracellular electrical signalling. Several studies have already been performed, providing experimental data on the tribological and electrical properties of these structures. The purpose of this work is to provide a better and broader characterization regarding the conductive aspect of these proteins, supplying the basis for a more precise and accurate use. Regarding the structure of microtubules, new impedance measurements were performed by coating these structures with gold nanoparticles, metal particles that were expected to have a significant contribution to conductivity. At the same time, regarding actin filaments, there are still no studies in literature that provide data on the electrical conductivity capacities of these structures; using the same techniques analysis performed on microtubules and considering the similarities between the two structural proteins, we gathered the same conductivity measurements for different concentrations of the filaments themselves, also verifying any differences between globular and polymerized actin. As first aspect, the results of these measurements showed how the photodeposited nanoparticles on the microtubules enhanced the ability of these proteins to conduct current; regarding the actin filaments, two relevant characteristics have been identified: the polymerized actin, arranged in filaments, has a lower impedance than its globular counterpart and, consistently with the initial hypotheses, at increasing concentrations higher conductivities correspond.