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Spirulina-templated metal microcoils with controlled helical structures for THz electromagnetic responses.

Kamata K, Piao Z, Suzuki S, Fujimori T, Tajiri W, Nagai K, Iyoda T, Yamada A, Hayakawa T, Ishiwara M, Horaguchi S, Belay A, Tanaka T, Takano K, Hangyo M - Sci Rep (2014)

Bottom Line: Spirulina varies its diameter, helical pitch, and/or length against growing environment.Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils.A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.

View Article: PubMed Central - PubMed

Affiliation: 1] Iyoda Supra-Integrated Material Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), 4259 Nagatsuta-Cho, Midori-Ku, Yokohama, Kanagawa 226-8503, Japan [2] Research Society for Biotemplate Technology, 4259 Nagatsuta-Cho, Midori-Ku, Yokohama, Kanagawa 226-8503, Japan.

ABSTRACT
Microstructures in nature are ultrafine and ordered in biological roles, which have attracted material scientists. Spirulina forms three-dimensional helical microstructure, one of remarkable features in nature beyond our current processing technology such as lithography in terms of mass-productivity and structural multiplicity. Spirulina varies its diameter, helical pitch, and/or length against growing environment. This unique helix is suggestive of a tiny electromagnetic coil, if composed of electro-conductive metal, which brought us main concept of this work. Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils. Structural parameters of the microcoil can be controlled by the cultivation conditions of Spirulina template and also purely one-handed microcoil can be fabricated. A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.

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Related in: MedlinePlus

Left-handed (LH) Spirulina-templated microstructures.The Spirulina basically forms LH helix but its structural parameters such as helical pitch, length, number of turns, and handedness are of variety based on a kind of strains. Sensitive strain, NIES-46, gradually tightens the helical pitch as the cultivation proceeded with stronger light intensity and higher temperature. The systematic adjustment of the helical pitch, Lfree/N, can be demonstrated; (a)-(e), LH template-1 to -5. (f) Linear strain was prepared by the pure cultivation of laboratory-derived single trichome. The biotemplating process was successfully carried out to generate the copper μcoils whose structures are followed by those of LH templates: (coil number, Lfree/N); (g) LH μcoil-1, 77 μm; (h) LH μcoil-2, 55 μm; (i) LH μcoil-3, 27 μm; (j) LH μcoil-4, 20 μm; (k) LH μcoil-5, 16 μm. (l) The straight copper wire was also properly templated from the linear strain.
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f2: Left-handed (LH) Spirulina-templated microstructures.The Spirulina basically forms LH helix but its structural parameters such as helical pitch, length, number of turns, and handedness are of variety based on a kind of strains. Sensitive strain, NIES-46, gradually tightens the helical pitch as the cultivation proceeded with stronger light intensity and higher temperature. The systematic adjustment of the helical pitch, Lfree/N, can be demonstrated; (a)-(e), LH template-1 to -5. (f) Linear strain was prepared by the pure cultivation of laboratory-derived single trichome. The biotemplating process was successfully carried out to generate the copper μcoils whose structures are followed by those of LH templates: (coil number, Lfree/N); (g) LH μcoil-1, 77 μm; (h) LH μcoil-2, 55 μm; (i) LH μcoil-3, 27 μm; (j) LH μcoil-4, 20 μm; (k) LH μcoil-5, 16 μm. (l) The straight copper wire was also properly templated from the linear strain.

Mentions: The LH helix of Spirulina is a common structure found in nature and easily obtained as the stock strain from culture collections. Under the conventional cultivation condition10, average feature size of the LH Spirulina (Fig. 2a) were 6 μm in wire diameter (d), 43 μm in coil diameter (D), 174 μm in free length of coil (Lfree), 74 μm in coil pitch (Lfree/N), 2.4 in turn number (N), and 29 ° in pitch angle (α) (for graphical illustration of the symbols, see Fig. S1). The number of Spirulina in 1 mL increased from 102 to 105 within one week (Methods and Fig. S2). During the cultivation, the d, D, and Lfree/N remained with narrow size distributions (around 5–15% of relative standard deviation, RSD), while the Lfree had a higher RSD around 20% because Spirulina grows along the long axis direction (Fig. S3). It has been known that the Spirulina forms various helical features and even linear shape under different environments. In this study, the Lfree/N was systematically controlled by varying cultivation temperature and light intensity (Methods and SI-II)11. The series of LH Spirulina with five different helical features in Fig. 2 are numbered as LH template-1 to -5. Linear Spirulina often found in laboratory cultivation of regular helical strains was obtained in pure culture (Fig. 2f). Such flexible morphologies against the environment can achieve distinction as microstructured-materials separately from commonly-used genetic control.


Spirulina-templated metal microcoils with controlled helical structures for THz electromagnetic responses.

Kamata K, Piao Z, Suzuki S, Fujimori T, Tajiri W, Nagai K, Iyoda T, Yamada A, Hayakawa T, Ishiwara M, Horaguchi S, Belay A, Tanaka T, Takano K, Hangyo M - Sci Rep (2014)

Left-handed (LH) Spirulina-templated microstructures.The Spirulina basically forms LH helix but its structural parameters such as helical pitch, length, number of turns, and handedness are of variety based on a kind of strains. Sensitive strain, NIES-46, gradually tightens the helical pitch as the cultivation proceeded with stronger light intensity and higher temperature. The systematic adjustment of the helical pitch, Lfree/N, can be demonstrated; (a)-(e), LH template-1 to -5. (f) Linear strain was prepared by the pure cultivation of laboratory-derived single trichome. The biotemplating process was successfully carried out to generate the copper μcoils whose structures are followed by those of LH templates: (coil number, Lfree/N); (g) LH μcoil-1, 77 μm; (h) LH μcoil-2, 55 μm; (i) LH μcoil-3, 27 μm; (j) LH μcoil-4, 20 μm; (k) LH μcoil-5, 16 μm. (l) The straight copper wire was also properly templated from the linear strain.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4017220&req=5

f2: Left-handed (LH) Spirulina-templated microstructures.The Spirulina basically forms LH helix but its structural parameters such as helical pitch, length, number of turns, and handedness are of variety based on a kind of strains. Sensitive strain, NIES-46, gradually tightens the helical pitch as the cultivation proceeded with stronger light intensity and higher temperature. The systematic adjustment of the helical pitch, Lfree/N, can be demonstrated; (a)-(e), LH template-1 to -5. (f) Linear strain was prepared by the pure cultivation of laboratory-derived single trichome. The biotemplating process was successfully carried out to generate the copper μcoils whose structures are followed by those of LH templates: (coil number, Lfree/N); (g) LH μcoil-1, 77 μm; (h) LH μcoil-2, 55 μm; (i) LH μcoil-3, 27 μm; (j) LH μcoil-4, 20 μm; (k) LH μcoil-5, 16 μm. (l) The straight copper wire was also properly templated from the linear strain.
Mentions: The LH helix of Spirulina is a common structure found in nature and easily obtained as the stock strain from culture collections. Under the conventional cultivation condition10, average feature size of the LH Spirulina (Fig. 2a) were 6 μm in wire diameter (d), 43 μm in coil diameter (D), 174 μm in free length of coil (Lfree), 74 μm in coil pitch (Lfree/N), 2.4 in turn number (N), and 29 ° in pitch angle (α) (for graphical illustration of the symbols, see Fig. S1). The number of Spirulina in 1 mL increased from 102 to 105 within one week (Methods and Fig. S2). During the cultivation, the d, D, and Lfree/N remained with narrow size distributions (around 5–15% of relative standard deviation, RSD), while the Lfree had a higher RSD around 20% because Spirulina grows along the long axis direction (Fig. S3). It has been known that the Spirulina forms various helical features and even linear shape under different environments. In this study, the Lfree/N was systematically controlled by varying cultivation temperature and light intensity (Methods and SI-II)11. The series of LH Spirulina with five different helical features in Fig. 2 are numbered as LH template-1 to -5. Linear Spirulina often found in laboratory cultivation of regular helical strains was obtained in pure culture (Fig. 2f). Such flexible morphologies against the environment can achieve distinction as microstructured-materials separately from commonly-used genetic control.

Bottom Line: Spirulina varies its diameter, helical pitch, and/or length against growing environment.Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils.A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.

View Article: PubMed Central - PubMed

Affiliation: 1] Iyoda Supra-Integrated Material Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), 4259 Nagatsuta-Cho, Midori-Ku, Yokohama, Kanagawa 226-8503, Japan [2] Research Society for Biotemplate Technology, 4259 Nagatsuta-Cho, Midori-Ku, Yokohama, Kanagawa 226-8503, Japan.

ABSTRACT
Microstructures in nature are ultrafine and ordered in biological roles, which have attracted material scientists. Spirulina forms three-dimensional helical microstructure, one of remarkable features in nature beyond our current processing technology such as lithography in terms of mass-productivity and structural multiplicity. Spirulina varies its diameter, helical pitch, and/or length against growing environment. This unique helix is suggestive of a tiny electromagnetic coil, if composed of electro-conductive metal, which brought us main concept of this work. Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils. Structural parameters of the microcoil can be controlled by the cultivation conditions of Spirulina template and also purely one-handed microcoil can be fabricated. A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.

Show MeSH
Related in: MedlinePlus