Hiroyuki Kawada

Kagawa University, Takamatsu-shi, Kagawa-ken, Japan

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Publications (4)6.98 Total impact

  • Yoshio Tanaka · Hiroyuki Kawada · Mitsuru Ishikawa · Hiroyuki Kitajima ·
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    ABSTRACT: Here we propose a collision-free sorting method for optically controlled dynamic micro-arrays. The beads forming a two-dimensional M×N lattice array can be sorted in arbitrary order by the collision-free cyclic shifts of four beads and six beads. A mathematical proof based on group theory and the experimental result with the time-sharing optical tweezers are described.
    01/2011; 46(4):253-255. DOI:10.9746/sicetr.46.253
  • Y. Tanaka · H. Kawada · S. Tsutsui · M. Ishikawa · H. Kitajima ·
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    ABSTRACT: Dynamic microarrays have great flexibility and potential as tools for advancing research in diagnostics and biomedical fields. In contrast with static microarrays such as DNA-chip using micro-spots of the bio-molecules, dynamic microarrays use a mobile substrate, usually micro-beads coated with bio-molecules. To realize the dynamic microarray, micro-bead handling techniques are essential, allowing us to transport the selected bead, and immobilize them for signal detection. Laser manipulation, known as optical tweezers, is one of the most suitable techniques for arranging and handling micro-beads. We have developed a multi-arm laser manipulation system with an excellent user-interface and realtime image processing functions. In this paper, we report a new approach for fully-automated assembly of a versatile dynamic micro-bead array. The beads, dispersed in a pipetted liquid on a cover glass, can be simultaneously trapped and sorted into a desired order, using multiple optical tweezers to transport the beads along collision-less paths guided by both computer vision and knowledge database techniques. Two typical examples are demonstrated. One is the fully-automated assembly of a 3x3 micro-bead array and its handling in 3D space. The other is the collision-free sorting of an array’s elements. We also describe the experimental apparatus used in these demonstrations. KeywordsOptical tweezers–Micromanipulation–Dynamic microarray–μ-TAS–Hough Transform
    01/2010: pages 5-7;
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    ABSTRACT: Dynamic micro-bead arrays offer great flexibility and potential as sensing tools in various scientific fields. Here we present a software-oriented approach for fully automated assembly of versatile dynamic micro-bead arrays using multi-beam optical tweezers combined with intelligent control techniques. Four typical examples, including the collision-free sorting of array elements by bead features, are demonstrated in real time. Control algorithms and experimental apparatus for these demonstrations are also described.
    Optics Express 12/2009; 17(26):24102-11. DOI:10.1364/OE.17.024102 · 3.49 Impact Factor
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    ABSTRACT: Automated optical trapping of non-spherical objects offers great flexibility as a non-contact micromanipulation tool in various research fields. Computer vision control enables fruitful applications of automated manipulation in biology and material science. Here we demonstrate fully-automated, simultaneous, independent trapping and manipulation of multiple non-spherical objects using multiple-force optical clamps. Customized real-time feature recognition and trapping beam control algorithms are also presented.
    Optics Express 10/2008; 16(19):15115-22. DOI:10.1364/OE.16.015115 · 3.49 Impact Factor