|
|
The field of nanomedicine
has the potential to end disease as we know it, but it's not without risk.
Back in December of 1959, Richard Feynman gave his
now-famous lecture titled There's Plenty of Room at the Bottom, during
which he essentially anticipated what we now call nanotechnology. Feynman
never mentioned the word "nanotechnology" in his talk, and it
wasn't until the 1980s that nanotech researchers began regularly citing his
lecture, but what he did do was posit the amazing possibilities afforded by
miniaturization.
While it's true that we don't yet have the
capabilities Feynman envisioned – of building "a billion tiny
factories, models of each other, which are manufacturing simultaneously"
from the bottom up, atom by atom – nanotechnology (the science of
things at the nanometer or molecular scale) is already a large part of our
modern economy. As fabrication techniques become more cost effective and
applications in more areas are discovered, the sky's the limit.
One of the biggest opportunities we see on the
horizon is in nanomedicine, which is simply the
application of nanotechnology to medicine; i.e., the diagnosis and treatment
of disease. According to the recent study Nanomedicine(s)
Under the Microscope by Ruth Duncan of Valencia, Spain's Polymer
Therapeutics Lab and Rogerio Gaspar of Lisbon,
Portugal's Nanomedicine & Drug Delivery Systems
Group, nanomedicine "encompasses the three
main nanotechnology areas being developed for healthcare applications:
- "Diagnostics, sensors and surgical tools
that are used outside the patient.
- "Innovative imaging agents and monitoring
technologies that can be used for diagnostic and sensing applications;
from cells to patients.
- "Innovative technologies and biomaterials
(sometimes combined with cell therapy) that are used for drug delivery,
for tissue engineering, and to promote tissue repair. Some applications
require only ex vivo manipulations, but most require patient
administration via any one of a number of different routes (e.g.,
topical, oral, parenteral, pulmonary, surgical implantation etc)."
The roots of modern nanomedicine
can be traced back to at least the 19th century – but
perhaps the most famous example is Paul Ehrlich, who coined the term
"magic bullet" and championed the concept of cell-targeted
therapies. And while more than 40 products have completed the journey from
the lab to routine clinical use, the science is still really in its infancy.
Thus, articles in the popular press often overhype it at both ends of the
spectrum – either as a technological revolution already able to address
countless unmet medical needs or a dangerous science that will end up
wreaking havoc on our health. In the decades to come there's no telling how
far nanomedicine will go (as optimists we're
betting it will be something closer to the former than the latter), but the
current state of the art lies between the two extremes.
Fears about the potential toxicity of nanomedicine, though often overblown, are not without
merit. Nanoparticles are so small they have virtually unrestricted access to
the human body and are able to evade detection by the body's immune system as
well as pass through the blood-brain barrier. While such traits are what make
nanoparticles so useful in medicine, it's also what makes them potentially
harmful if they are not biodegradable and therefore able to accumulate in
organs like the liver. Nevertheless, the benefits of nanomedicine
seem to outweigh the risks in many if not most scientists' eyes, which has resulted in huge advances in the area over the past
several years, particularly in drug delivery and diagnostic and imaging
techniques.
Nanomedicines on the market today comprise first-generation
technologies like liposomes (artificially prepared vesicles composed of the
same material as a cell membrane that can be filled with drugs) and PEGylated pharmaceuticals (drugs that have been altered
through the covalent attachment of polyethylene glycol polymer chains to mask
the agent from the host's immune system). Meanwhile, technologies such as
iron-oxide nanoparticles (which are well established magnetic-resonance
imaging agents) and various nanocrystals are finding
new indications in numerous late-stage clinical trials.
While these first-generation nanomedicines
have shown great promise in imaging and treating disease, they are not
without their drawbacks. For example, polymers like PEG are not
biodegradable, which may cause harm due to accumulation within lysosomes
(cellular organelles that contain enzymes to break down waste materials and
cellular debris) after high doses or chronic administration.
Despite the potential drawbacks and challenges to
overcome, the future of nanomedicine looks bright.
Although moving from lab to patient is a long and trying process, the fact
that labs around the world are announcing scientific breakthroughs on
virtually a daily basis speaks to the opportunities that lie ahead.
One new technique that is currently in the
development stage delivers anti-cancer drugs in packets or
"bubbles" of nanoparticles to the tumor, where they accumulate.
Ultrasound can then be directed at the target, popping the bubbles and
releasing the drug within a well-defined area. Another unrelated line of
research uses antibodies to deliver a packet of gold nanoparticles to the
cancer cell. An intense, focused laser beam is then used to explode the nanobubble, bursting the cell. And yet another oncological
effort is Kanzius RF Therapy, which aims to insert
metallic nanoparticles in or around cancerous cells and then excite these
particles using radio waves. The energy from the radio waves heats the metal,
which burns the cancerous cell cluster.
Some more of the recent lab breakthroughs include:
- Using polymer-coated gold nanoparticles to
enhance detection of circulating tumor cells (CTCs) and provide a means
of detecting cancer earlier.
- Using lipid-polymer nanoparticles to engineer a
formulation of docetaxel (a well-established
anti-mitotic chemotherapy drug) to improve the efficiency of chemoradiotherapy.
- Using nanofibers of
polyvinyl alcohol and polyethylene oxide to encapsulate antibiotics,
which gives them the ability to destroy even the most drug-resistant
bacteria so completely that scientists described the remains as mere
"ghosts."
- Using modified gold nanoparticles to develop a
leukemia-DNA biosensor capable of diagnosing the disease in less than 20
minutes.
- Using carbon nanoparticles to encapsulate chemotherapeutic
drugs for enhanced treatment of head and neck cancers.
Meanwhile, emerging materials like carbon nanotubes
and quantum dots are also entering the fray. The unique geometry and
electrochemical and thermal properties of carbon nanotubes make them
potentially well-suited as drug carriers, imaging agents, or even gene
delivery agents – although potential toxicity must still be considered,
especially given the fact that their physical form draws comparison to
carcinogenic asbestos fibers, according to Duncan and Gaspar. Quantum dots
are also some of the most widely investigated new biomedical nanomaterials for use in tumor imaging and in theranostics (the merger of therapeutics and
diagnostics).
The holy grail of nanomedicine
is, of course, in vivo nanorobots that would
have the ability to travel directly to problem cells and repair them on the
fly at the cellular level without trauma, pain, or disfigurement. In other
words, the end of disease as we know it. While we're still decades – if
not centuries – away from such a scenario, researchers at Harvard have
developed a nanorobotic device made from DNA that could seek out specific cell targets and
deliver molecular instruction… like telling cancer cells to kill themselves.
From an investor's point of view, a lot of the
interesting advancements in nanomedicine are coming
from early-stage private companies or academic labs. For example, innovative nanomedicine leaders like Cerulean Pharma,
Selecta Biosciences, and BIND Biosciences are all privately held,
venture-backed companies. But the coming years should bring IPOs of numerous nanomedicine firms as they advance their science and
therapeutics into clinical trials. In the meantime, one company that might be
worth a look is Arrowhead Research Corporation (NASDAQ:ARWR), a
clinical-stage nanomedicine company and majority
owner of Calando Pharmaceuticals, which developed a breakthrough
drug-delivery system called RONDEL (RNAi/oligonucleotide
nanoparticle delivery) that extends the reach of RNAi
therapy. While we're not formally recommending that you go out and buy shares
of ARWR, it may be worth some research on your part if you are looking to get
positioned in the burgeoning field of nanomedicine.
[Breakthroughs in biotechnology have opened up a new
world of investment opportunities, particularly in companies revolutionizing
cancer treatment. Learn which four firms are
especially worthy of a close look.]
|
|
