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Teixeira LM, Strickland A, Mark SS, Bergkvist M, Sierra-Sastre Y, Batt CA. Entropically driven self-assembly of Lysinibacillus sphaericus S-layer proteins analyzed under various environmental conditions. Macromol Biosci 2010; 10:147-55. [PMID: 19637150 DOI: 10.1002/mabi.200900175] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
S-Layer proteins are an example of bionanostructures that can be exploited in nanofabrication. In addition to their ordered structure, the ability to self-assembly is a key feature that makes them a promising technological tool. Here, in vitro self-assembly kinetics of SpbA was investigated, and found that it occurs at a rate that is dependent on temperature, its concentration, and the concentration of calcium ions and sodium chloride. The activation enthalpy (120.81 kJ . mol(-1)) and entropy (129.34 J . mol(-1) . K(-1)) obtained infers that the incorporation of monomers incurs in a net loss of hydrophobic surface. By understanding how the protein monomers drive the self-assembly at different conditions, the rational optimization of this process was feasible.
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Song HZ, Usuki T, Ohshima T, Sakuma Y, Kawabe M, Okada Y, Takemoto K, Miyazawa T, Hirose S, Nakata Y, Takatsu M, Yokoyama N. Site-controlled quantum dots fabricated using an atomic-force microscope assisted technique. NANOSCALE RESEARCH LETTERS 2006; 1:160. [PMCID: PMC3246671 DOI: 10.1007/s11671-006-9012-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An atomic-force microscope assisted technique is developed to control the position and size of self-assembled semiconductor quantum dots (QDs). Presently, the site precision is as good as ± 1.5 nm and the size fluctuation is within ± 5% with the minimum controllable lateral diameter of 20 nm. With the ability of producing tightly packed and differently sized QDs, sophisticated QD arrays can be controllably fabricated for the application in quantum computing. The optical quality of such site-controlled QDs is found comparable to some conventionally self-assembled semiconductor QDs. The single dot photoluminescence of site-controlled InAs/InP QDs is studied in detail, presenting the prospect to utilize them in quantum communication as precisely controlled single photon emitters working at telecommunication bands.
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Affiliation(s)
- HZ Song
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - T Usuki
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - T Ohshima
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - Y Sakuma
- Nanomaterials Laboratory, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan
| | - M Kawabe
- Nanomaterials Laboratory, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan
| | - Y Okada
- Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, 305-8773, Japan
| | - K Takemoto
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - T Miyazawa
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - S Hirose
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - Y Nakata
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - M Takatsu
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
| | - N Yokoyama
- Nanotechnology Research center, Fujitsu Lab. Ltd., Morinosato-Wakamiya 10-1, Atsugi, Kanagawa, 243-0197, Japan
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