Silica-spider silk composites

Following nature's lead in designing materials with novel properties, researchers have prepared composites based on a combination of spider silk and silica (Proc. Natl. Acad. Sci. USA 2006, 103, 9428). Seashell, bone, and other naturally occurring composite materials derive their unique properties from the microscopic blend of the organic and inorganic building blocks from which they are composed. That materials synthesis strategy led Cheryl Wong Po Foo and David L. Kaplan of Tufts University and their coworkers to combine the structural and morphological properties of biological silica with the strength and self-assembling nature of silk. To prepare the new composites, the team joined a silica-controlling peptide derived from diatoms (algae with silica-impregnated cell walls) with a spider-silk protein to form fusion (chimeric) proteins. The synthetic proteins were then used to form films and fibers with silica precipitates that feature a narrow particle size distribution (shown). The composites' morphology, structure, and other properties can be tailored by controlling the processing conditions, the team says.