Optical transparency and electrical conductivity of intermediate filaments in Müller cells and single-wall carbon nanotubes

Abstract

Presently we investigated the electrical conductivity and optical transparency of Müller cell intermediate filaments. For comparison, the same properties were also explored in the model system of single-wall carbon nanotubes. We report the method of separation and purification of porcine (Sus scrofa domestica) intermediate filaments, extracted from the retinal Müller cells. We also report experimental and theoretical methods of measurements and calculations of the resistivity and light transmission yield by the intermediate filaments and single wall carbon nanotubes. The measured resistivity values were (4.7 ± 0.3) × 10−4 and (2.8 ± 0.2) × 10−4 Ω⋅m−1⋅cm2 at 5 °C (278 K), for the intermediate filaments and single wall carbon nanotubes, respectively, being quite close to those of typical metals. We report a method for measuring the light energy transmission by these nanostructures. We found that they efficiently transfer excitation energy along their axis, with the light reemitted at their other end. The measured yields of transferred light energy were 0.50 ± 0.03 and 0.26 ± 0.02 for intermediate filaments and single wall carbon nanotubes, respectively (λexc = 546.1 nm; T = 288 K). The reported results are novel, providing a direct confirmation of the earlier proposed quantum mechanism of light energy transport in the inverted retina of vertebrates. Our data also show that Müller cell intermediate filaments, in addition to their cytoskeletal function, are capable of providing for the light energy transfer within the inverted retina. The data obtained enable a significant progress in our understanding of the high-contrast vision of the vertebrate eyes. The most important conclusion of the current study is the discovery of light energy propagation along natural biological nanofibers (intermediate filaments). This result is completely novel and unique, being reported for the first time.