Browsing by Author "Yoshikawa, Hiroshi Y."

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Bidirectional polymorphic conversion by focused femtosecond laser irradiation
(2020-06-01)
Wu, Chi-Shiun
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Yoshikawa, Hiroshi Y.
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Sugiyama, Teruki
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交大名義發表
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應用化學系
We present bidirectional polymorphic conversion of L-phenylalanine by focused femtosecond laser irradiation. When the femtosecond laser beam is focused at an air/solution interface of its unsaturated solution, the plate-like anhydrous crystals are generated from the laser focus. This crystal nucleation is realized by local concentration increase achieved by femtosecond laser trapping, which is the first demonstration of femtosecond laser trapping-induced crystallization. Furthermore, the whisker-like monohydrate crystals are produced by continuing the femtosecond laser irradiation on the surface of the plate-like crystals. On the contrary, when a focused femtosecond laser irradiation is applied to the whisker-like monohydrate crystals, the plate-like crystals are formed, meaning that an unstable phase is successfully produced from a stable phase. The dynamics and mechanism of the bidirectional polymorphic conversion are explained from the viewpoint of the nucleation rate theory considering solution concentration around the surface of laser-induced cavitation bubbles. (c) 2020 The Japan Society of Applied Physics
Growth Promotion of Targeted Crystal Face by Nanoprocessing via Laser Ablation
(2019-10-10)
Wu, Chi-Shiun
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Ikeyama, Jun
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Nakabayashi, Seiichiro
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Sugiyama, Teruki
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Yoshikawa, Hiroshi Y.
Control of crystal shape is an indispensable step for various applications of crystalline products. However, obtaining the desired crystal shape by conventionally tuning environmental conditions (temperature, additives, etc.) cannot always be reached. Recently, we have developed an innovative approach for spatiotemporal control of crystal growth of proteins and amino acids by locally modifying crystal structure (e.g., formation of screw dislocations) via femtosecond (fs) laser ablation. In this work, to clarify the appropriate laser condition for controlling the shape of single crystals with minimized damage, we first systematically investigated the dependence of pulse duration on laser ablation and crystal growth of L-phenylalanine (L-Phe). By using a laser system with tunable pulse durations from fs to nanoseconds (ns), we found fs laser ablation can offer nanometer-sized, sharp etching of which diameter was smaller than the diffraction limit. By utilizing such nanoprocessing via fs laser ablation for promoting the growth of a targeted crystal face, we successfully demonstrated the preparation of a bulky crystal of L-Phe, which is difficult to be obtained by conventional crystallization methods.
Laser ablation for protein crystal nucleation and seeding
(2014)
Yoshikawa, Hiroshi Y.
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Murai, Ryota
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Adachi, Hiroaki
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Sugiyama, Shigeru
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Maruyama, Mihoko
With the recent development in pulsed lasers with ultrashort pulse widths or wavelengths, spatially precise, low- damage processing by femtosecond or deep- UV laser ablation has shown promise for the production of protein single crystals suitable for X- ray crystallography. Femtosecond laser processing of supersaturated solutions can shorten the protein nucleation period or can induce nucleation at low supersaturation, which improves the crystal quality of various proteins including membrane proteins and supra- complexes. In addition to nucleation, processing of protein crystals by femtosecond or deep- UV laser ablation can produce single crystalline micro- or macro- seeds without deterioration of crystal quality. This tutorial review gives an overview of the successful application of laser ablation techniques to nucleation and seeding for the production of protein single crystals, and also describes the advantages from a physico-chemical perspective.
Plasmonic Manipulation of Sodium Chlorate Chiral Crystallization: Directed Chirality Transfer via Contact-Induced Polymorphic Transformation and Formation of Liquid Precursor
(2020-08-05)
Niinomi, Hiromasa
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Sugiyama, Teruki
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Tagawa, Miho
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Ujihara, Toru
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Omatsu, Takashige
The control of crystallization not only impacts the production of functional crystalline materials or pharmaceuticals but also provides profit to investigate the fundamental mechanism of crystallization. Recently, we have revealed that plasmonic optical tweezers (POT) can "manipulate" the crystallization of a pharmaceutical compound from its aqueous solution by optically trapping molecular clusters, offering a novel strategy to control crystallization. Here we report a variety of unique crystallization phenomena by applying POT to sodium chlorate (NaClO3) chiral crystallization from an aqueous microdroplet loaded on a plasmonic substrate. Plasmon excitation significantly promotes crystallization intermediated by an achiral metastable crystal as a precursor. Also, the direction of the creeping of the resulting chiral crystal can be controlled. By utilizing this phenomenon, we achieved the directed chirality transfer from the chiral crystal to the achiral crystal via a forced contact-induced polymorphic transformation by intentionally making creeping chiral crystal contact with an achiral crystal. Moreover, we captured, by in situ optical microscopic observation, a liquid precursor that intermediates the NaClO3 achiral crystallization for the first time. Our results highlight the plasmonic manipulation of crystallization opening a new door not only to control crystallization but also to investigate the unprecedented fundamental process of crystallization.
Spatially Precise, Soft Microseeding of Single Protein Crystals by Femtosecond Laser Ablation
(2012-09-01)
Yoshikawa, Hiroshi Y.
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Hosokawa, Yoichiroh
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Murai, Ryota
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Sazaki, Gen
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Kitatani, Tomoya
We developed a spatially precise, soft microseeding method for the production of single protein crystals that are suitable for X-ray crystallographic studies. We used focused femtosecond laser pulses to produce, via multiphoton absorption processes, seed crystals from small regions (similar to 1 mu m(2)) of crystals. Hen egg-white lysozyme seed crystals, produced in this manner, grew to be single crystals without any deterioration in their crystallinity. We also validated the technique using polycrystals for the membrane protein, acriflavine resistance protein B, for which single crystals are very difficult to obtain. In addition, we found that the shape of a tetragonal lysozyme crystal prepared from the seed could be controlled by altering the time interval between the initiation of crystallization and laser ablation. We also tried to comprehend the mechanism of femtosecond laser-induced microseeding. We visualized the ablated surfaces of the lysozyme crystals by atomic force microscopy and by laser confocal microscopy combined with differential interference microscopy. The results obtained in this study clearly demonstrate that femtosecond laser ablation of protein crystals is based on a photomechanical process, which ejects crystal fragments with little thermal damage. Femtosecond laser ablation is indeed very promising to produce high quality protein seed crystals from polycrystals or cracked crystals that are not suitable for X-ray diffraction studies.
Spatiotemporal Dynamics of Laser-Induced Molecular Crystal Precursors Visualized by Particle Image Diffusometry
(2019-12-05)
Hanasaki, Itsuo
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Okano, Kazuki
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Yoshikawa, Hiroshi Y.
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Sugiyama, Teruki
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交大名義發表
We have succeeded in label-free visualization of spatiotemporal dynamics of laser-induced crystal precursors in aqueous solutions. The tracking-free evaluation of the diffusion-coefficient field for the observation domain with tens of micrometers on a side from microscopy movie data is realized by particle image diffusometry (PID). PID revealed the time fluctuation of coverage composition with the nonuniform space distribution of diffusion coefficients by the prenucleation clusters. Furthermore, the results indicate the existence of a loose aggregation domain of prenucleation clusters where the order of viscosity corresponds to that of honey.