The University of Osaka · Physics and Astronomy
Professor Mihoko Maruyama's research lab specializes in the fundamental mechanisms of crystal growth and polymorphism control, with a focus on understanding and manipulating the selective crystallization of metastable phases in pharmaceuticals and biominerals. The lab employs advanced in-situ analytical techniques—such as phase-shift interferometry, laser irradiation, ultrasonic stimulation, and confocal microscopy—to investigate the role of molecular chirality, solution dynamics, and external stimuli in directing crystal morphology and phase selection. Their work bridges materials science, physical chemistry, and biomedicine, particularly in applications related to kidney stone pathology and the development of stable, high-purity drug polymorphs.
Figures are computed from collected data and may differ slightly.
The regulation of calcite mineralization by chiral biological molecules is one of the fundamental unresolved issues at the interface between biological, geological, and physical sciences. Here we address the role of chirality of l-aspartic acid (l-Asp), a model additive, in the regulation of the growth of calcite crystals. We apply phase-shift interferometry to nonintrusively monitor in-situ the morphology of the surface and quantify the velocity of propagation of the edges of the unfinished cry
A new method for selective crystallization of the metastable phase (form II) of acetaminophen is described. To obtain form II, we prepared a highly supersaturated solution (σI = 3.7) and then applied ultrasonic irradiation at different frequencies. Without ultrasonic irradiation, spontaneous crystallization did not occur within one month in the highly supersaturated condition (σI = 3.7). When ultrasonic irradiation at 28 kHz was applied, form II preferentially crystallized. Therefore, we conclud
We describe a new method for the selective crystallization of the metastable phase (α-form) of indomethacin. To obtain the α-form, we prepared a highly supersaturated solution and then introduced forcible nucleation techniques, namely, laser irradiation and magnetic stirring. When the laser irradiated near the side wall, the α-form crystallized within 24 h. The α-form crystals showed temporal stability for at least 8 months in air ambient at room temperature. We conclude that control of the lase
The pathogenesis of kidney stone formation includes multi-step processes involving complex interactions between mineral components and protein matrix. Calcium-binding proteins in kidney stones have great influences on the stone formation. The spatial distributions of these proteins in kidney stones are essential for evaluating the in vivo effects of proteins on the stone formation, although the actual distribution of these proteins is still unclear. We reveal micro-scale distributions of three d
The selective crystallization of aspirin form II is exceedingly difficult, because the similarity of the crystal structures of form I and form II enable them to intergrow. We succeeded in crystallizing a pure form II crystal by laser irradiation with a precise condition control. The crystal was identified by Raman spectroscopy and in situ observation of the phase transformation from form II into form I. Accordingly, we conclude that this laser-induced crystallization would be applicable to a var
To grow protein crystals of better quality, there still exists an open question whether a solution flow should be suppressed or intentionally introduced. To obtain a comprehensive understanding of the effects of a solution flow, we directly measured the velocities of individual elementary steps (on {110} faces of tetragonal lysozyme crystals) under a forced solution flow, for the first time, by laser confocal microscopy combined with differential interference contrast microscopy. When we used cr
Abstract We report a new method of obtaining the metastable phase form II crystals of acetaminophen. Solution-mediated phase transformation (SMPT) from trihydrate into form II is utilized to obtain form II crystals. SMPT is triggered by seeding form II crystals into a saturated solution including trihydrate crystals, which are less stable than form II crystals. Form II seed crystals gradually grew at the expense of the dissolving trihydrate crystals, and finally, all the trihydrate crystals in s
We report a novel method for crystallizing the metastable polymorph form II of acetaminophen by using a plastic ball during ultrasonic irradiation. The presence of a plastic ball during ultrasonic irradiation of aqueous acetaminophen solution effectively increased the probability and reduced the induction time of form II crystallization. This method facilitated both laboratory- and large-scale production of form II crystals. Our method has significant advantages for practical application of form
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