Injectable nanogel can monitor blood-sugar levels and secrete
insulin when needed. CAMBRIDGE, Mass. -- Ask John Santini,
Michael Cima, and Robert Langer about potential applications for
the microchip they're reporting in the January 28, 1999 issue of
Nature, and settle back for an enthusiastic tour of a future
that could include jewelry that emits different scents depending
on your mood, and "pharmacies" that could be swallowed or
implanted under the skin and programmed for the delivery of
precise amounts of drugs at specific times. The chip behind
their excitement is the first of its kind: it can store and
release different chemicals, on demand, from tiny reservoirs
built into its silicon structure. Apply a small electrical
voltage to a given reservoir, and the thin gold cap covering it
dissolves, releasing the chemical inside. "The Nature paper
shows that this basic concept works," said Dr. Cima, Sumitomo
Electric Industries Professor of Ceramic Processing. "The next
step is to do the engineering to make th