Making Tiny Plastic Particles to Deliver Lifesaving
Medicines

Justin Hanes |
'Technology Review' picks Justin Hanes as one of top 100
young innovators
By Phil Sneiderman Homewood
Many medications such as therapeutic DNA, insulin and
human growth hormone must enter the body through painful
injections, but a Johns Hopkins researcher is seeking to
deliver the same treatment without the sting.
Justin
Hanes wants to pack the drugs inside microscopic
plastic spheres that can be inhaled painlessly. Inside the
lungs, the particles should dissolve harmlessly, releasing
the medicine at a predetermined pace.
"We've made significant progress," said Hanes, an
assistant professor in the Whiting School's
Department of
Chemical and Biomolecular Engineering, "especially when
you consider all of the challenges we've faced in designing
and synthesizing these new biomaterials."
For one thing, the polymer used in making such
particles must dissolve slowly in the body, releasing the
medicine inside over a prescribed period of hours, days or
even weeks. Also, this material must be strong and
flexible, so that the particles do not crack or crumble
before delivering their treatment. At the same time, the
particles must not stick together, forming clumps that will
prevent proper travel through the air passages. Once the
particles deposit in the lungs, some therapies will require
that they cross the thick mucus lining of air passages
prior to releasing their medicinal cargo. Finally, the
material must not trigger a strong immune response, in
which the body's natural defense system attacks a particle
before it has delivered its dose.
Hanes and his lab colleagues have overcome many of
these hurdles, publishing their research results in
peer-reviewed journals. Last year, in an issue of
Biomaterials, Hanes' team, including associate
research scientist Jie Fu and Ph.D. candidate Jennifer
Fiegel, reported that it had synthesized a new type of
porous polymer particles capable of releasing drugs in an
environment resembling the deep lungs. Importantly, the
components used to create these plastic microspheres were
FDA-approved materials for other medical applications,
making it more likely they will pose no health hazards to
humans in their new polymeric form. Recent works by Hanes,
Ph.D. candidate Michelle Dawson and associate professor
Denis Wirtz has focused on understanding how to alter the
design of drug-carrying particles so that they can more
efficiently cross the mucus lining in the lungs to reach
their cell targets underneath. This work will appear
shortly in the Journal of Biology Chemistry, Biotechnology
Progress and the Journal of Aerosol Medicine.
Earlier this year, in Proceedings of the National
Academy of Sciences, Hanes, Wirtz and Junghae Suh, a
doctoral candidate, reported that their nanoscopic
particles appear to be able to efficiently deliver
therapeutic genes by carrying DNA directly to the cell
nucleus. Someday, Hanes said, this technique also may prove
useful in delivering toxic cancer-fighting drugs only to
cells affected by the disease.
For his research accomplishments, Hanes is being
recognized in the October issue of MIT's Technology Review
as one of the world's top 100 young innovators. The TR100,
chosen by the publication's editors and an elite panel of
judges, consists of 100 individuals under age 35 whose
innovative work in technology has a profound impact on
today's world. Nominees are recognized for their
contributions in transforming the nature of technology in
industries such as biotechnology, computing, energy,
medicine, manufacturing, nanotechnology, telecommunications
and transportation.
Hanes has focused much of his attention on the lungs
because they possess several advantages over other drug
delivery routes. When medicine is swallowed, it must pass
through the stomach, where it may be degraded by digestive
acids. Injections may avoid this problem, but they also are
painful and may be difficult for some patients to
administer to themselves. Inhalation, however, as smokers
and asthmatics know, is generally a quick and painless
method of getting a drug into the body. Still, Hanes noted,
"the lungs are pretty sacred ground. You have to be very
conservative about what you put in there."
As a doctoral student at MIT, Hanes played a leading
role in developing porous polymer drug delivery particles
coated with a special surfactant native to the lung. The
surfactant is designed to fool the body into thinking these
particles belong in the lungs, warding off an immune
response. In 1999, Hanes and his colleagues received a U.S.
patent for this invention; Hanes currently holds eight U.S.
patents for advanced drug delivery applications.
At Johns Hopkins, he is building upon this research by
synthesizing improved inhalation particles, each about a
10th of the diameter of a human hair. He soon hopes to
begin testing their safety and effectiveness in animal
models and eventually in human trials. Hanes also is trying
to produce even smaller particles that could be used to
deliver powerful medications directly into diseased cells,
while leaving normal tissue unharmed.
Hanes' early research has been supported by several
grants and awards, including one from the Whitaker
Foundation.
Related Web Sites:
Justin Hanes
Johns Hopkins Department of Chemical and Biomolecular
Engineering
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2003
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