Biomimetic Materials by Freeze Casting

Abstract

Natural materials, such as bone and abalone nacre, exhibit exceptional mechanical properties, a product of their intricate microstructural organization. Freeze casting is a relatively simple, inexpensive, and adaptable materials processing method to form porous ceramic scaffolds with controllable microstructural features. After infiltration of a second polymeric phase, hybrid ceramic-polymer composites can be fabricated that closely resemble the architecture and mechanical performance of natural bone and nacre. Inspired by the narwhal tusk, magnetic fields applied during freeze casting can be used to further control architectural alignment, resulting in freeze-cast materials with enhanced mechanical properties.

Structure and mechanical properties of selected protective systems in marine organisms

“…Given its presence in the bones and teeth of humans, it has garnered a significant amount of research in the biomedical field, producing a number of bioinspired designs with a focus on biomedical materials and implants [9,[57][58][59][60][61]. Biogenic hydroxyapatite often forms around a collagen scaffold that directs growth (Fig.…”

“…• Crush resistant, high toughness ceramics based upon the tough and highly mineralized shells of abalone [9,108]: the nacre-inspired brick-and-mortar structure of these ceramics are fabricated through an ice templating process called "freeze casting" [57] followed by compression and infiltration with a second phase. They can be infiltrated with polymers or metals to form composites whose toughness is significantly greater than that of their base constituents.…”

Reproducibility of ZrO2-based freeze casting for biomaterials

“…The freeze casting process has been greatly researched over the past decade as an attractive method to fabricate bioinspired materials and composites [1][2][3][4][5][6][7][8][9]. The process itself is carried out in four steps: (1) a slurry of solid loading (e.g.…”

“…water) is prepared, (2) the slurry is directionally frozen in a controlled manner, causing the liquid freezing agent to template the solid loading, (3) the frozen scaffold is freeze dried in order to remove the freezing agent and create a green body, and (4) the green body is sintered in order to form a final, porous scaffold where the ice crystals have been converted into aligned pores [1,3,4,8]. Once these porous scaffolds have been fabricated, they can be infiltrated with polymers or metals in order to create two-phase interpenetrating composites [5,[10][11][12].…”

New functional insights into the internal architecture of the laminated anchor spicules of Euplectella aspergillum

“…structure-property relationship | structural biomaterial | biocomposite | variational analysis B iological structural materials such as nacre, tooth, bone, and fish scales (1-9) often exhibit remarkable mechanical properties, which can be directly attributed to their unique structure and composition (10)(11)(12)(13)(14)(15). Through the detailed analysis of these complex skeletal materials, useful design lessons can be extracted that can be used to guide the synthesis of synthetic constructs with novel performance metrics (16)(17)(18)(19)(20). The complex and mechanically robust cage-like skeletal system of the hexactinellid sponge Euplectella aspergillum has proved to be a particularly useful model system for investigating structure-function relationships in hierarchically ordered biological composites (21)(22)(23)(24)(25).…”