Bioinspired Control of Calcium Phosphate Liesegang Patterns Using Anionic Polyelectrolytes.

Young Shin Cho,István Lagzi,Sung Ho Yang,Miyoung Moon,Gábor Holló

doi:10.1021/acs.langmuir.1c02980

Abstract

The Liesegang phenomenon is a spontaneous pattern formation, which is a periodic distribution of the precipitate discovered in diffusion-limited systems. Over the past century, it has been experimentally attempted to control the periodicity of patterns and structures of precipitates by varying the concentration of the hydrogel or electrolytes, adding organic or inorganic impurities, and applying an electric or pH field. In this work, the periodic patterns of calcium phosphate were manipulated with an anionic macromolecular additive inspired by bone mineralization in which various noncollagenous proteins are involved in the formation of a polymer-induced liquid precursor. The periodic patterns were systematically controlled by adjusting the amount of poly(acrylic acid), and they were numerically simulated by adjusting the threshold concentration of nucleation. The change of the pattern is explained by improved stability and directional diffusion of the intermediate.

Highlights

The spontaneous self-organization and self-assembly of components into controllable microstructures and periodic patterns have gained growing interest in the field of material science.[1−4] The Liesegang phenomenon is one of the spontaneous pattern formation, which is a periodic distribution of the precipitate discovered in diffusion-limited systems
In the early stage of mineralization, it is generally postulated that amorphous calcium phosphate (ACP) stabilized by noncollagenous proteins (NCPs) has a liquidlike property called the polymer-induced liquid precursor (PILP).[35,36]
Eq 3 was an essential step to simulate the asymmetric microstructure of a single band, and k2 is much smaller than other reaction rate constants, which means that the aggregation of intermediates is a rate-determining step and that the overall precipitation patterns mainly result from eq 3.21 In this work, the Liesegang pattern varied by a function of PAA additives was successfully simulated by applying a threshold concentration (α*) in eq 4 and introducing a reversible step describing the interaction between Ca2+ and PAA (Figure 5)

Summary

■ INTRODUCTION

The spontaneous self-organization and self-assembly of components into controllable microstructures and periodic patterns have gained growing interest in the field of material science.[1−4] The Liesegang phenomenon is one of the spontaneous pattern formation, which is a periodic distribution of the precipitate discovered in diffusion-limited systems. It was demonstrated that the single-diffusion system in which the Ca(NO3)2·4H2O solution was overall structure of each band was dependent on the diffusive properties of ACP precursors.[21] anionic polymers have been used in biomimetic approaches to generate poured into the preformed gelatin gel mixture. The previous reports, soluble organic molecules have been added to control polymorphs, composition, and hierarchical organization of CaCO3 and BaCO3.39,40 generated periodic spatiotemporal development of a single band was obtained from the setup for a cylindrical hydrogel, which was used in our previous work.[21] Three-dimensional (3D) curves were recorded using a camcorder (HDR-CX360, Sony, Japan) and processed with the line patterns were formed only at the surface of a single crystal, and profile function of MATLAB (R2017a, The Mathworks, Inc., USA). The morphology of CaP precipitates was investigated by field periodic patterns of the Liesegang bands can be precisely controlled by adopting the role of NCPs that stabilize the intermediates during biomineralization.

■ RESULT AND DISCUSSION

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES