New nanocomposite combines strength of spider silk and toughness of silica

Filed in archive Materials on June 20, 2006

Scientists in the US have combined spider silk with biological silica to make an extremely strong composite nanomaterial that could be used in industrial and medical applications. The new nanomaterial boasts the flexibility and tensile strength of silk and the toughness of silica, according to a report at physicsweb:

Silica is widely found in biological systems, where it supports and protects single-celled organisms, such as diatoms. It also exists in the skeletons of some higher animals and even in plants. Spider silk, meanwhile, is a highly flexible material that has a high tensile strength. What's more, it can self assemble to produce well-defined sheet-like structures.

The new composite was made by David Kaplan at Tufts University in Massachusetts and his colleagues, who used genetic engineering to make a cloned spider silk protein that can form films and fibers. By mixing this material with biosilica - from the proteins of diatoms - in aqueous solution, the researchers were able to create a composite nanomaterial with exceptional mechanical properties. The researchers found that the elliptically shaped silica particles attached themselves to the protein fibers, which as a result became "sticky".

According to Kaplan and co-workers, the new material could be used in industrial and biomedical applications, and to make new composites. An example is novel biomaterials for making artificial bone.

The researchers say that their technique might allow the production of other tough materials and composites that are difficult to fabricate using traditional industrial methods. (photo physicsweb.org)