Atomic water channel controlling remarkable properties of a single brain microtubule: Correlating single protein to its supramolecular assembly Satyajit Sahu a , Subrata Ghosh a , Batu Ghosh c , Krishna Aswani d , Kazuto Hirata b , Daisuke Fujita a , Anirban Bandyopadhyay a,n a Nano Characterization Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan b Vortex Dynamics Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan c Materials and Nano-architectronics, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan d Surface Characterization Group, Nano Characterization Unit Advanced Key Technologies Division, National Institute for Materials Science, 1-2-1 Sengen, Main Bldg, Room-815 Tsukuba, 305-0047, Japan article info Article history: Received 7 January 2013 Received in revised form 20 February 2013 Accepted 21 February 2013 Available online 15 March 2013 Keywords: Microtubule Tubulin protein Scanning tunneling microscopy Four probe electronic device Atomic force microscopy Resonance spectroscopy abstract Microtubule nanotubes are found in every living eukaryotic cells; these are formed by reversible polymerization of the tubulin protein, and their hollow fibers are filled with uniquely arranged water molecules. Here we measure single tubulin molecule and single brain-neuron extracted microtubule nanowire with and without water channel inside to unravel their unique electronic and optical properties for the first time. We demonstrate that the energy levels of a single tubulin protein and single microtubule made of 40,000 tubulin dimers are identical unlike conventional materials. Moreover, the transmitted ac power and the transient fluorescence decay (single photon count) are independent of the microtubule length. Even more remarkable is the fact that the microtubule nanowire is more conducting than a single protein molecule that constitutes the nanowire. Microtubule's vibrational peaks condense to a single mode that controls the emergence of size independent electronic/optical properties, and automated noise alleviation, which disappear when the atomic water core is released from the inner cylinder. We have carried out several tricky state-of-the-art experiments and identified the electromagnetic resonance peaks of single microtubule reliably. The resonant vibrations established that the condensation of energy levels and periodic oscillation of unique energy fringes on the microtubule surface, emerge as the atomic water core resonantly integrates all proteins around it such that the nanotube irrespective of its size functions like a single protein molecule. Thus, a monomolecular water channel residing inside the protein-cylinder displays an unprecedented control in governing the tantalizing electronic and optical properties of microtubule. & 2013 Elsevier B.V. All rights reserved. 1. Introduction In spite of incredible claims, the carbon nanotube could not revolutionize the industry due to complicacy in isolating metallic and semiconducting nanotube, and the DNA adventure (Dekker and Ratner, 2001; Fink and Schönenberger, 1999; Rakitin et al., 2001; Storm et al., 2001; Zhang et al., 2002) turned critical due to its extreme conformational-fluctuations on the atomic scale. The 25 nm wide and from 200 nm to 25 μm long microtubule nanotube stores cellular dynamics codes as doped drugs inside its main constituent tubulin protein similar to ATGC that stores DNA's genetic code. Nature has a catalog of microtubule's cellular code, in all eukaryotes, plants, animals, fungi and Protista kingdom for 3.5 billion years. It forms a complex network inside neurons and living cells controlling fundamental life functions via massively parallel and hierarchical information processing (Barabási and Albert, 1999; Butts, 2009; Gerhart et al., 1997; Moriya et al., 2001; Song et al., 2005; Strogatz, 2001). Since single tubulin and microtubule properties were never studied extensively, here we cater state-of-the-art technologies to unravel the electronics and information processing in these systems (Mange and Tomassini, 1998; Sipper, 2002; Teuscher et al., 2003; Zhang and Gao, 2012). As microtubules are dipped into an extremely noisy cellular soup (Braun et al., 2003; Roberts et al., 2011; Shibata and Ueda, 2008; Szendro et al., 2001a, 2001b), the properties studied therein contain artifacts, while noise-free bio-material studies are irrelevant to real bio-systems (Roberts et al., 2011). Yet, microtubule is a rigid elastic string unlike DNA and its composition of lattice mixtures is many folds more resourceful than carbon nanotube with no isolation issues—a prime candidate for the state-of-the-art inves- tigations to unravel its embedded nanotechnologies. The naturally produced drug molecules were automatically doped inside the tubulin protein to add unique properties to the Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/bios Biosensors and Bioelectronics 0956-5663/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.bios.2013.02.050 n Corresponding author. Tel.: þ81 298592167. E-mail addresses: anirban.bandyo@gmail.com, anirban.bandyopadhyay@nims.go.jp (A. Bandyopadhyay). Biosensors and Bioelectronics 47 (2013) 141–148