Mimicking the Biomolecular Control of Calcium Oxalate Monohydrate Crystal Growth: Effect of Contiguous Glutamic Acids

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• 作者：Bernd Grohe ; Susanna Hug ; Aaron Langdon ; Jari Jalkanen ; Kem A. Rogers ; Harvey A. Goldberg ; Mikko Karttunen ; Graeme K. Hunter
• 刊名：Langmuir
• 出版年：2012
• 出版时间：August 21, 2012
• 年：2012
• 卷：28
• 期：33
• 页码：12182-12190
• 全文大小：557K
• 年卷期：v.28,no.33(August 21, 2012)
• ISSN：1520-5827

文摘

Scanning confocal interference microscopy (SCIM) and molecular dynamics (MD) simulations were used to investigate the adsorption of the synthetic polypeptide poly(l-glutamic acid) (poly-glu) to calcium oxalate monohydrate (COM) crystals and its effect on COM formation. At low concentrations (1 渭g/mL), poly-glu inhibits growth most effectively in 001 directions, indicating strong interactions of the polypeptide with {121} crystal faces. Growth in 010 directions was inhibited only marginally by 1 渭g/mL poly-glu, while growth in 100 directions did not appear to be affected. This suggests that, at low concentrations, poly-glu inhibits lattice-ion addition to the faces of COM in the order {121} > {010} 鈮?{100}. At high concentrations (6 渭g/mL), poly-glu resulted in the formation of dumbbell-shaped crystals featuring concave troughs on the {100} faces. The effects on crystal growth indicate that, at high concentrations, poly-glu interacts with the faces of COM in the order {100} > {121} > {010}. This mirrors MD simulations, which predicted that poly-glu will adsorb to a {100} terrace plane (most calcium-rich) in preference to a {121} (oblique) riser plane but will adsorb to {121} riser plane in preference to an {010} terrace plane (least calcium-rich). The effects of different poly-glu concentration on COM growth (1鈥? 渭g/mL) may be due to variations between the faces in terms of growth mechanism and/or (nano)roughness, which can affect surface energy. In addition, 1 渭g/mL might not be adequate to reach the critical concentration for poly-glu to significantly pin step movement on {100} and {010} faces. Understanding the mechanisms involved in these processes is essential for the development of agents to reduce recurrence of kidney stone disease.