Microchips release drugs on demand
NEW YORK, Jan 27, 1999 (Reuters Health) -- Pills and patches may someday
be replaced with a new drug delivery system --
a microchip that is implanted or swallowed, and then delivers drug doses
on demand, according to the professor who
invented the dime-sized prototype.
Professor Robert Langer of the Massachusetts Institute of Technology
(MIT) in Cambridge, told Reuters Health that the
little chip could be connected to a tiny battery and microprocessor so
that drugs would be delivered automatically
according to a preset schedule or when needed through some type of
manual operation or remote control.
``Picture a dish the size of a dime with 1,000 little wells,'' he said,
describing the prototype chip that he and two other
professors at MIT developed. ``The wells can be filled with drugs or
chemicals. This prototype has only 34 wells, but
there could just as well be 1,000.''
A research article on the implantable ``pharmacy-on-a-chip'' is
published this week in the journal Nature. The prototype, a
silicon microchip developed by Langer and his colleagues, is dotted with
34 wells, or reservoirs, the size of pinpricks. Each
can hold about 25 nanoliters of chemical in solid, liquid, or gel form.
Each reservoir is ``capped'' with a thin layer of gold
that serves as an anode in an electrochemical reaction. Other electrodes
on the surface of the microchip serve as
cathodes. To release the contents of a particular reservoir, an
electrical volt is applied between the anode covering that
reservoir and a cathode, which dissolves the thin, gold membrane.
Most implants and patches currently on the market deliver drugs
continuously. The ``controlled release'' microchip would
be able to deliver multiple drugs according to a complex schedule.
The new microchip was constructed at MIT's Microsystems Technology
Laboratory. According to a statement issued by
MIT, other potential uses of the chip include diagnostic tests,
cosmetics, jewelry programmed to release different scents
depending on the wearer's mood, or entertainment, such as in televisions
that could release different scents keyed to
broadcast scenes or advertisements.
SOURCE: Nature 1999;397:335-338.
--
Judith Richards, London, Ontario, Canada
<[log in to unmask]>
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