Tough, Strong, and Sticky
Some of the year’s coolest new materials were made possible by mimicking the nanoscale features of natural structures. For years, researchers have been trying to make materials that are as tough as nacre, the material that lines abalone shells, with limited success. This year, materials scientists created a new ceramic that’s better than nacre; it could eventually be used as a structural material for buildings and vehicles. Like nacre, the new ceramic is a composite of a hard material and a gluey one. Researchers have also finally outdone the gecko, which uses arrays of nanoscale hairs on its paws to scale walls and ceilings. Arrays of carbon nanotubes with two layers–one vertically aligned, the other tangled–mimic gecko-foot structures but are 10 times as sticky.
Super-Resolution Imaging and a $10 Microscope
Metamaterials are usually lauded for their potential to direct light around an object, completely hiding it. This year brought the first designs for acoustic metamaterials, which will shield objects from sound. But the earliest application of metamaterials, usually made up of metals carefully structured on the nano- or microscale to tailor their interactions with light, is likely to be in super-resolution imaging. Light microscopes with resolutions on the scale of biological molecules will help biologists understand not just what proteins are at work in diseased cells, but also how they interact with other molecules to cause disease. Nicholas Fang of the University of Illinois is using metamaterials made up of metals structured on the nanoscale to make superlenses, which increase the resolution of biological light microscopes by an order of magnitude.
Other groups are taking a different approach to super-resolution imaging, developing new fluorescent probes and new optical systems to make the inner workings of cells visible. The highest-resolution 3-D light microscope ever made allowed researchers to see the inner workings of the metabolizing mitochondria, the subcellular organelle that powers cells, for the first time.
Meanwhile, a $10 microscope developed this year at Caltech uses cheap starting materials, including microfluidics and the same light-sensing chips found in digital cameras. Its imaging quality equals that of conventional microscopes. If integrated into a PDA, it could bring sophisticated imaging technology to rural doctors.
This year, researchers at Tufts University demonstrated that they can use proteins from silkworm cocoons to make biodegradable optical devices. They hope that their devices will eventually be implanted during surgery and used to monitor patients for signs of recovery.
The year also saw advances in materials for tissue engineering. It’s been difficult to mimic the structures of the heart, liver, and other tissues in the lab. A stretchy polymer developed at MIT can withstand the mechanical stresses of beating heart tissue, and its honeycomb structure encourages heart-muscle cells to orient naturally, which makes for heart-tissue patches that contract like real heart muscle.