Nano Communication Networks 2 (2011) 16–24 Contents lists available at ScienceDirect Nano Communication Networks journal homepage: www.elsevier.com/locate/nanocomnet Design of self-organizing microtubule networks for molecular communication Akihiro Enomoto a,∗ , Michael J. Moore a , Tatsuya Suda a , Kazuhiro Oiwa b a Department of Computer Science, Donald Bren School of Information and Computer Sciences, University of California, Irvine, CA 92697-3435, United States b Kobe Advanced ICT Research Center, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan article info Article history: Available online 19 May 2011 Keywords: Biological computing and communication Molecular motor Microtubule Self organization Microtubule network abstract In this paper, we investigated approaches to form a self-organizing microtubule network. Microtubules are protein filaments naturally occurring in the aqueous environment of cells. A microtubule network connects multiple nano- or micro-scale objects (i.e., nanomachines). In the paper, we propose two approaches to form an in vitro microtubule network in a self-organizing manner. The first approach utilizes polymerization and depolymerization of microtubules. The second approach utilizes molecular motors to reorganize a microtubule network. In addition, we conducted preliminary in vitro experiments to investigate the feasibility of the proposed approaches. In the preliminary experiments, we observed that a few sender and receiver nanomachines were interconnected with the first approach, and that distinct topologies of microtubules were reorganized with the second approach. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction 1.1. Molecular communication system Molecular communication is a possible solution for nanomachines to communicate with other nanomachines, where the communication is performed by transmit- ting molecules representing information. Nanomachines are natural or artificially synthesized assemblies and are made of biological molecules that perform limited computation [25], sensing [5], or actuation [31] by us- ing chemical reactions. Molecular communication allows multiple nanomachines to cooperate and achieve com- plex functions that cannot be accomplished by a sin- gle nanomachine. In generic molecular communication, sender nanomachines encode a message (e.g., DNA code) onto biological molecules (e.g., mRNA), rather than encod- ing onto electrons, electromagnetic or acoustic waves. ∗ Corresponding author. Tel.: +1 949 824 4105. E-mail address: enomoto@ics.uci.edu (A. Enomoto). The sender nanomachines transmit information en- coded molecules (referred to as ‘‘information molecules’’) into the environment. These information molecules are then transported through the environment to the location of the receiver nanomachines with a certain probability. The receiver nanomachines then decode the message from the information molecules (e.g., Ribosome reads genetic instruction from mRNA and synthesizes a protein). Through communication at such a scale, creation of entirely new applications which require cooperation of multiple nanomachines can be performed. Such applica- tions may include distributed nanomachine computing [8], human health monitoring [15], bionano structure fabri- cation [28], programmable lab-on-a-chip [30], and bio- sensors [9]. Biological systems (e.g., biological cells) use several forms of molecular communication to exchange infor- mation. For example, biological systems have developed active and passive transport methods to transport informa- tion molecules [1] for molecular communication. In pas- sive transport, information molecules move by random 1878-7789/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.nancom.2011.04.002