title: Control of microtubule trajectory within an electric field by altering surface charge density.
abstract: One of challenges for using microtubules (MTs) driven by kinesin motors in microfluidic environments is to control their direction of movement. Although applying physical biases to rectify MTs is prevalent, it has not been established as a design methodology in conjunction with microfluidic devices. In the future, the methodology is expected to achieve functional motor-driven nanosystems. Here, we propose a method to guide kinesin-propelled MTs in multiple directions under an electric field by designing a charged surface of MT minus ends labeled with dsDNA via a streptavidin-biotin interaction. MTs labeled with 20-bp or 50-bp dsDNA molecules showed significantly different trajectories according to the DNA length, which were in good agreement with values predicted from electrophoretic mobilities measured for their minus ends. Since the effective charge of labeled DNA molecules was equal to that of freely dispersed DNA molecules in a buffer solution, MT trajectory could be estimated by selecting labeling molecules with known charges. Moreover, the estimated trajectory enables to define geometrical sizes of a microfluidic device. This rational molecular design and prediction methodology allows MTs to be guided in multiple directions, demonstrating the feasibility of using molecular sorters driven by motor proteins.
authors.affiliation: Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Isozaki
authors.affiliation: Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan.
authors.forename: Suguru
authors.initials: S
authors.lastname: Ando
authors.affiliation: Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan.
authors.forename: Tasuku
authors.initials: T
authors.lastname: Nakahara
authors.affiliation: Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Shintaku
authors.affiliation: Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Kotera
authors.affiliation: Department of Mechanical and Biomedical Engineering, University of Michigan, Ann Arbor 48109, Michigan, USA.
authors.forename: Edgar
authors.initials: E
authors.lastname: Meyhöfer
authors.affiliation: 1] Department of Micro Engineering, Kyoto University, Kyoto 615-8540, Japan [2] Precursory Research for Embryonic Science and Technology from the Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Yokokawa
mesh_terms: D001710:Biotin / Q000737:chemistry / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004560:Electricity; D005464:Fluorobenzenes / Q000737:chemistry; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism; D046210:Microfluidic Analytical Techniques; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000737:chemistry* / Q000378:metabolism; D019809:Streptavidin / Q000737:chemistry / Q000378:metabolism
chemical_list: C513915:AlexaFluor 488 carboxylic acid tetrafluorophenyl ester; D005464:Fluorobenzenes; D001710:Biotin; D004247:DNA; D019809:Streptavidin; D016547:Kinesins