Self‐Organized Spatiotemporal Mineralization of Hydrogel: A Simulant of Osteon

Abstract

Nature creates fascinating self‐organized spatiotemporal patterns through the delicate control of reaction‐diffusion dynamics. As the primary unit of cortical bone, osteon has concentric lamellar architecture, which plays a crucial role in the mechanical and physiological functions of bone. However, it remains a great challenge to fabricate the osteon‐like structure in a natural self‐organization way. Taking advantage of the nonequilibrium reaction in hydrogels, a simple mineralization strategy to closely mimic the formation of osteon in a mild physiological condition is developed. By constructing two reverse concentration gradients of ions from periphery to interior of cylindrical hydrogel, spatiotemporal self‐organization of calcium phosphate in concentric rings is generated. It is noteworthy that minerals in different layers possess diverse contents and crystalline phases, which further guide the adhesion and spread of osteoblasts on these patterns, resembling the architecture and cytological behavior of osteon. Besides, theoretical data indicates the predominate role of ion concentrations and pH values of solution, in good accordance with experimental results. Independent of precise instruments, this lifelike method is easily obtained, cost‐efficient, and effectively imitates the mineral deposition in osteon from a physiochemical view. The strategy may be expanded to develop other functional material patterns via spatiotemporal self‐organization.

Anisotropic Liesegang pattern for the nonlinear elastic biomineral-hydrogel complex

“…Although the biomineralized complex with HAP shell–inter-HD–HAP core structure was reported, the correlation between the anisotropic structure and mechanical property was not revealed; meanwhile, the bioactivity of patterned HAPs was proved through the selective growth of the preosteoblast cells ( 61 ). Here, rheological studies were performed to comprehend the correlation between the anisotropic Liesegang pattern and the nonlinear elasticity.…”

Bioinspired Multiscale Mineralization: From Fundamentals to Potential Applications

“…Wu et al used the reaction-diffusion process to control the distribution and morphology of CaP minerals on the hydrogel substrate through three-step mineralization. [84] Due to the existence of ion concentration gradient, calcium ions and phosphate ions diffuse from the outside of the hydrogel to the inside, and OH − flows in the opposite direction. After reaction-diffusion, CaP concentric rings with three-layered structures were formed in the hydrogel (Figure 5B).…”

“…B) CaP minerals of different morphologies were obtained by the reaction diffusion process in the PAM hydrogel matrix. Reproduced with permission [84]. Copyright 2021, John Wiley and Sons.…”

A novel CT-responsive hydrogel for the construction of an organ simulation phantom for the repeatability and stability study of radiomic features

“…Finally, by changing the temperature of external conditions, an ionic crosslinking network is established in the covalent crosslinking network. Among them, the secondary network cross-linked by calcium ions belongs to reversible dynamic cross-linking, and some calcium ions in the free state will be induced with sulfate ions in the initiator to generate calcium sulfate in situ, [28][29][30][31] which enables the hydrogel to accurately adjust the CT value through the intensity of calcium ions in the secondary network. This process allows accurate control of the CT value of the hydrogel, making it suitable for use as a model material with characteristics similar to human tissue for medical imaging and analysis purposes.…”