Tufts University researchers, led by David L. Kaplan, a chair of biomedical engineering, have designed an interesting nanocomposite that demonstrates the strength of its ingredients: spider silk and silica.
Bioengineers at Tufts University have created a new fusion protein that for the first time combines the toughness of spider silk with the intricate structure of silica. The resulting nanocomposite could be used in medical and industrial applications, such as growing bone tissue…
Silica provides structural support to diatoms (single-celled organisms known for their remarkable nanostructural details) while silk proteins from spiders and silkworms are more flexible, stronger and able to self-assemble into readily defined structures. The Tufts researchers were able to design and clone genetic fusions of the encoding genes for these two proteins, and then generate these genetically engineered proteins into nanocomposites at ambient temperatures using only water. In contrast, high temperatures and harsh conditions are typically required by geochemical and industrial synthesis of silica in the laboratory.
Another remarkable detail about the spider silk-silica composite is its size. While past tests using silica have formed silica particles with a diameter between 0.5 and 10 nanometers, the silk-glass composite has a diameter size distribution between 0.5 and 2 nanometers. The smaller, more uniform size will provide better control and more options for processing, which would be “important benefits for biomedical and specialty materials,” according to the research.
Kaplan says this new chimeric protein could lead to a variety of biomedical materials that restore tissue structure and function, including bone repair and regeneration. Other likely applications involve more basic areas of materials science and engineering, including “green chemistry,” which will prevent or reduce pollution.