Supersmart
Multidisciplinary teams of scientists are joining forces to design materials with built in stimulus response. These smart materials can be customized with sensitivities to signals such as heat, light, impact, pulses of electric currents, and motion. While chemists research the realm of the supersmall with the mission to develop enzyme-like tools to construct supersmart self-assembling materials, tissue engineers are building polymer scaffolds that support the growth of human organs and tissues. Robert Langer from the Massachusetts Institute of Technology (MIT) and Jay Vacanti, from Harvard Medical School, initiated this burgeoning field of tissue engineering and have successfully synthesized new biodegradable polymer systems that have supported the growth of livers, cartilage (nose, ears), and nerves. The cells that are seeded on these structures are smart “natural” materials; they manage to recreate their respective tissue functions. At the University of Illinois at Urbana-Champaign, Scott White studies self-repairing plastics. He is an associate professor in aeronautical and astronautical engineering and takes his design inspiration from the rhinoceros horn. He and a multidisciplinary team of scientists designed a biomimetic polymer with embedded capsules full of “healing” liquid that, upon rupture, self-corrects cracks in plastic and fiberglass. According to White, this self-healing plastic can be used anywhere synthetic polymer is used now, from microchips to the wings on a full-size aircraft.
SELF-TIGHTENING (left). An image sequence of a thermoplastic shape-memory polymer developed by Andreas Lendlein shows the transition from the temporary shape of a straight rod to a self-tightening knot. It has use as a suture that ties itself during minimally invasive surgical procedures.
SELF HEALING (right). An optical microscope image of Scott White’s self-healing plastic. The microcapsules are colored red and the catalyst is black (the dark specs in the image). The healing agent has penetrated through the crack front, the solid red line across the center of the image.
