Biologists at MIT have engineered a nano material that behaves like soap and could strip away grease more efficiently than conventional detergents. Shuguang Zhang, associate director of the Center for Biomedical Engineering, and his colleagues created the material from fragments of proteins called peptides, which self-assemble into different structures. In this case, the peptides formed nanotubes.Instead of using naturally occurring proteins, the researchers employed peptides synthesized from scratch-each with a hydrophobic (water-repelling) tail and a hydrophilic (water-attracting) head. When placed in water, the peptides formed rings, which then stacked on top of each other to form nanotubes 30 to 50 nanometers in diameter-about the size of a virus. While other research groups have made so-called surface-active agents-or “surfactants”-from organic materials, Zhang is the first to make a protein-based surfactant, which he calls a more gentle and less toxic material. Such protein structures could have other applications, as, for example, vesicles for delivering drugs to the body and scaffolds for building nanoscale electronic devices. Researchers could tailor the peptides to bind to semiconducting nanocrystals. The peptides could direct the nanoparticles into a desired configuration-say, a circuit-and, once removed, would leave behind the final device.