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Biomimetic synthesis of struvite with biogenic morphology and implication for pathological biomineralization.

Li H, Yao QZ, Wang YY, Li YL, Zhou GT - Sci Rep (2015)

Bottom Line: Recent studies have found that certain urinary proteins can efficiently inhibit stone formation.These discoveries are significant for developing effective therapies for stone disease, but the inhibition mechanism of crystallization remains elusive.Concentration-dependent experiments show that PASP can inhibit struvite growth and the inhibitory capacity increases with increasing PASP concentration, whereas aspartic acid monomers do not show a significant effect.

View Article: PubMed Central - PubMed

Affiliation: CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, P. R. China.

ABSTRACT
Recent studies have found that certain urinary proteins can efficiently inhibit stone formation. These discoveries are significant for developing effective therapies for stone disease, but the inhibition mechanism of crystallization remains elusive. In the present study, polyaspartic acid (PASP) was employed as a model peptide to investigate the effect of urinary proteins on the crystallization and morphological evolution of struvite. The results demonstrate that selective adsorption/binding of PASP onto the {010} and {101} faces of struvite crystals results in arrowhead-shaped morphology, which further evolves into X-shaped and unusual tabular structures with time. Noticeably, these morphologies are reminiscent of biogenic struvite morphology. Concentration-dependent experiments show that PASP can inhibit struvite growth and the inhibitory capacity increases with increasing PASP concentration, whereas aspartic acid monomers do not show a significant effect. Considering that PASP is a structural and functional analogue of the subdomains of aspartic acid-rich proteins, our results reveal that aspartic acid-rich proteins play a key role in regulating biogenic struvite morphology, and aspartic acid residues contribute to the inhibitory capacity of urinary proteins. The potential implications of PASP for developing therapeutic agents for urinary stone disease is also discussed.

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Relationship between PASP concentrations and weight (a) or length (b) of struvite obtained in the concentration-dependent experiments.
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f5: Relationship between PASP concentrations and weight (a) or length (b) of struvite obtained in the concentration-dependent experiments.

Mentions: Moreover, in order to better understand the effect of PASP on struvite crystal growth, mineralization experiments with different concentrations of PASP were also carried out, and a 2 h mineralization time was deliberately chosen because our time-resolved experiments indicated that the orientation aggregation/assembly of the struvite subunits occurs between 1 and 2 h (Figure 3, panels b1 and c1). In the absence of PASP, a large number of long penniform crystals was obtained, with a length of ca. 190 μm (e.g., Figure 3, panel c2). However, when 0.1 mM of PASP was added, the product had a large X-shape with a length of ca. 100 μm, and some attached grains forming two intersecting lines on the surface could also be seen (Figure 4a). If the PASP concentration was increased to 0.2 mM, the X-shapes still dominated the crystallization habits, but the lengths were reduced to 50 μm (e.g., Figure 3, panel c1). At a PASP concentration of 0.4 mM, both X-shaped and short tabular habits coexisted, with a length of ca. 30 μm and ca. 20 μm, respectively (Figure 4b). When the PASP concentration reached 0.8 mM, all of the crystals had a short tabular habit and the mean length was 20 μm (Figure 4c). However, further increasing PASP concentration to 2 mM did not lead to a remarkable change in the shape and size of struvite (Figure 4d), only a reduced output. In order to unambiguously demonstrate the dependence of the yield and dimensions of the mineralized struvite on PASP, all trials were conducted five times to calculate a mean yield, and 30 particles from the SEM images were measured in each case to determine an average length. As shown in Figure 5, either the yield or dimensions of struvite dramatically decreases with an increase in the PASP concentration. Although the inhibitory effect on the dimension was tested at saturation after the addition of 0.8 mM of PASP, the yield of struvite consistently and dramatically decreases. It appears that PASP not only significantly impacts the morphology of struvite but also effectively inhibits the nucleation and growth of struvite.


Biomimetic synthesis of struvite with biogenic morphology and implication for pathological biomineralization.

Li H, Yao QZ, Wang YY, Li YL, Zhou GT - Sci Rep (2015)

Relationship between PASP concentrations and weight (a) or length (b) of struvite obtained in the concentration-dependent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296295&req=5

f5: Relationship between PASP concentrations and weight (a) or length (b) of struvite obtained in the concentration-dependent experiments.
Mentions: Moreover, in order to better understand the effect of PASP on struvite crystal growth, mineralization experiments with different concentrations of PASP were also carried out, and a 2 h mineralization time was deliberately chosen because our time-resolved experiments indicated that the orientation aggregation/assembly of the struvite subunits occurs between 1 and 2 h (Figure 3, panels b1 and c1). In the absence of PASP, a large number of long penniform crystals was obtained, with a length of ca. 190 μm (e.g., Figure 3, panel c2). However, when 0.1 mM of PASP was added, the product had a large X-shape with a length of ca. 100 μm, and some attached grains forming two intersecting lines on the surface could also be seen (Figure 4a). If the PASP concentration was increased to 0.2 mM, the X-shapes still dominated the crystallization habits, but the lengths were reduced to 50 μm (e.g., Figure 3, panel c1). At a PASP concentration of 0.4 mM, both X-shaped and short tabular habits coexisted, with a length of ca. 30 μm and ca. 20 μm, respectively (Figure 4b). When the PASP concentration reached 0.8 mM, all of the crystals had a short tabular habit and the mean length was 20 μm (Figure 4c). However, further increasing PASP concentration to 2 mM did not lead to a remarkable change in the shape and size of struvite (Figure 4d), only a reduced output. In order to unambiguously demonstrate the dependence of the yield and dimensions of the mineralized struvite on PASP, all trials were conducted five times to calculate a mean yield, and 30 particles from the SEM images were measured in each case to determine an average length. As shown in Figure 5, either the yield or dimensions of struvite dramatically decreases with an increase in the PASP concentration. Although the inhibitory effect on the dimension was tested at saturation after the addition of 0.8 mM of PASP, the yield of struvite consistently and dramatically decreases. It appears that PASP not only significantly impacts the morphology of struvite but also effectively inhibits the nucleation and growth of struvite.

Bottom Line: Recent studies have found that certain urinary proteins can efficiently inhibit stone formation.These discoveries are significant for developing effective therapies for stone disease, but the inhibition mechanism of crystallization remains elusive.Concentration-dependent experiments show that PASP can inhibit struvite growth and the inhibitory capacity increases with increasing PASP concentration, whereas aspartic acid monomers do not show a significant effect.

View Article: PubMed Central - PubMed

Affiliation: CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, P. R. China.

ABSTRACT
Recent studies have found that certain urinary proteins can efficiently inhibit stone formation. These discoveries are significant for developing effective therapies for stone disease, but the inhibition mechanism of crystallization remains elusive. In the present study, polyaspartic acid (PASP) was employed as a model peptide to investigate the effect of urinary proteins on the crystallization and morphological evolution of struvite. The results demonstrate that selective adsorption/binding of PASP onto the {010} and {101} faces of struvite crystals results in arrowhead-shaped morphology, which further evolves into X-shaped and unusual tabular structures with time. Noticeably, these morphologies are reminiscent of biogenic struvite morphology. Concentration-dependent experiments show that PASP can inhibit struvite growth and the inhibitory capacity increases with increasing PASP concentration, whereas aspartic acid monomers do not show a significant effect. Considering that PASP is a structural and functional analogue of the subdomains of aspartic acid-rich proteins, our results reveal that aspartic acid-rich proteins play a key role in regulating biogenic struvite morphology, and aspartic acid residues contribute to the inhibitory capacity of urinary proteins. The potential implications of PASP for developing therapeutic agents for urinary stone disease is also discussed.

Show MeSH