Prof. Marina Tsianou (Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York)
「Biomimetic Mineralization via Designer Macromolecules and Environments」
Living organisms are able to form morphologically diverse minerals produced in a complex manner and in media of specified compositions. In most biomineralization processes many soluble biopolymers exist in minute quantities; these control the nucleation, growth, orientation, and polymorph selection, leading to the formation of minerals with diverse biological functions and distinct properties such as corals, shells, otoliths, bones and teeth (beneficial mineralization), as well as pathological processes, e.g., bone disease, dental calculus, and renal stone formation. This presentation will highlight our recent efforts in exploiting bio-inspired strategies toward the fundamental understanding of the factors that control the nucleation and growth of important biominerals such as calcium carbonate, calcium oxalate, and calcium phosphate. We establish that water-soluble macromolecules (polyelectrolytes, polypeptides, surfactants) mimic in an effective way the role of soluble biomineralization polymers and can control the final morphology and polymorphic occurrence by face-selective adsorption on crystals (thermodynamic regime) and/or by temporarily stabilizing ‘less stable’ polymorphs (kinetic regime). Furthermore, we investigate the role of organic matrix as mediator of the mineralization and as provider of a structural framework for mechanical support. We employ hydrogels which serve as excellent models of the extracellular matrix microenvironment. Hydrogels, through their 3D-network structure, provide many small crystallization compartments where nucleation and growth are mostly controlled by the diffusion of ions through the matrix, thus resulting in lower nucleation densities and control over the growth. By judicious selection of the conditions we can control the local supersaturation, the structural framework for growth, and the final morphology of crystals. Our findings provide insights into the formation of organic-inorganic composite materials with the same specialization and complexity as those in nature.