( nd some bridges form between the layers...)Secrets of the sea yield stronger artificial bone

"These characteristics contribute to the scaffolding's mechanical toughness. Cracks don't propagate as easily and more energy is needed to break the material," says Tomsia. "This makes the scaffolding four times stronger than the porous hydroxyapatite materials currently used in bone substitutes."

In the future, the Berkeley Lab scientists hope to tailor the scaffolding so that it fosters bone tissue regeneration. To do this, the space between the scaffolding's layers can be filled with an organic polymer that degrades over the span of several weeks, liberating antibiotics and compounds that stimulate bone growth.

The idea is to place this dense hydroxyapatite-polymer composite in the body where new bone needs grow. Over time, as the polymer degrades, the scaffolding becomes more porous and the growth factor activates, prompting bone cells to invade the newly created pores.

"Porosity will be created in situ to allow bone growth," says Tomsia. "When the polymer degrades, bone cells can proliferate into the porous ceramic scaffolding, allowing old bone to fuse with new bone. We provide the body with scaffolding, and the rest of the work is done by cells."

The Berkeley Lab scientists also hope to create samples that are large enough to work with artificial joints. Their ice-templated fabrication technique also holds promise for many applications in addition to artificial bone. The scaffolding can be made from any solution, not just hydroxyapatite, and the space between the layers can be infiltrated with a wide range of molten metals, polymers, and resins.

Ultimately, their technique may enable the fabrication of new materials with properties that cannot be achieved by nature or conventional processing techniques. It combines nature's sophisticated architectures, which are designed over a wide range of length scales, with scientist
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Source:DOE/Lawrence Berkeley National Laboratory