Nature has many examples of self-assembly, and bioengineers are interested in copying these systems to create useful new materials or devices. Amyloid proteins, for example, can self-assemble into the tangled plaques associated with Alzheimer's disease -- but can also form very useful materials, such as spider silk, or biofilms around living cells. Researchers have now come up with methods to manipulate natural proteins so that they self-assemble into amyloid fibrils.