Jul 16, 2002
Nanomedicine makes it better
In 1966 the feature film Fantastic Voyage saw a team of scientists shrink a submarine - including its crew - and insert it into the bloodstream of a dying man. It being a Hollywood movie, the man was saved and the crew were successfully resized to live another day.
Roughly 40 years later, nanomedicine certainly hasn't brought us miniaturized doctors and nurses, but recent advances mean that inserting nanodevices (so-called nanobots) into blood vessels is almost out of the realms of science fiction. Cecilia Haberzettl, president of TechnoMed Strategic Partners, gives Liz Kalaugher an update.
LK: We've heard a lot about the promise of nanomedicine. What will it actually bring us?
CH: The advantages of nanomedicine are two-fold. In the short term we're looking at advances in drug discovery and drug delivery, as well as the continued miniaturization of analytical/ diagnostic procedures.
In the long term we're looking at the ability to do in vivo diagnostics coupled with much more targeted, focused therapy. Now we just do general drug therapy: sometimes it works and sometimes it doesn't, and some medications produce significant side-effects. If the promise of nanomedicine holds true, we'll be able to avoid those side-effects and we'll have better response to therapy because we'll know who to give it to and how to give it.
So how can nanotechnology aid drug discovery?
Nanotechnology gives us the ability to do analytical procedures in the lab on a much smaller scale. We can look for drug targets on a cellular basis as opposed to a multicellular or tissue basis, as we do now. Advances in biosensors and molecular probes will allow for more detailed examination of cellular processes. You will then be more effective in identifying molecular targets for drug development.
And what about drug delivery? What's the status there?
That's already happening. For example, you can take a drug and put it inside a nanoparticle. The nanoparticle could be any number of formulations - a carbon nanotube, a nanotube made out of something other than carbon, a structure like a silicon wafer with antibodies on it, or some other molecule that will bind the drug. That potentially allows you to give the drug in a smaller dose because you will be able to deliver it directly to the tissue of interest. Various nanoparticle drug formulations are under investigation in animal models and in early-stage human clinical studies.
Can you give some examples of nanomedicine that's under development?
Nanomedicine is well under way in oncology. One example is radiation therapy - Memorial Sloan-Kettering has developed what it calls a nanogenerator, where it actually injects the generator of radioactivity and targets it to the tissue. The device, a type of nanobot, goes directly to the tissue and gives small doses of radiation right at the site of the cancer, so you don't have all of the side-effects of radiation therapy.
At Ohio State University they've developed a mechanism to encapsulate pancreatic cells so that they remain live and continue to secrete insulin. You put these encapsulated cells into the bloodstream where they secrete insulin, and the antibodies can't get to them because they're inside a nanoparticle. You're not able to cure diabetes, but you can at least provide insulin to the body in a natural way without all of the problems of giving injections.
Advectus Life Sciences announced just recently that it has formally started animal studies for nanoparticles that cross the blood-brain barrier to treat brain tumours. In theory, provided that no negative data come up and regulatory approvals are granted, it could be ready to do human studies within 18-24 months.
What other areas will find nanomedicine of use?
Space travel. NASA is looking at the ability to do remote diagnostics and delivery of therapy to astronauts on the Space Shuttle. For example, when astronauts leave the Earth's atmosphere, they're subjected to radiation. NASA is working with universities to develop nanobots that would circulate through the blood and be able to detect radiation-damaged cells.
When a cell is damaged by radiation it expresses different proteins on its surface. The nanobot would detect those proteins and then repair the cell, either by giving it antioxidants or by enhancing the natural mechanisms of DNA repair by some technique yet to be defined. Or, if the damage is severe, the nanobot could trigger the cell to die. All of that could happen while the astronauts are up in space, while avoiding communication delays due to the distance from the Earth.
So what do you think is the timescale for seeing healing through nanobots?
It is difficult to predict the timescale - the realization of nanobots is an evolving process and advances continue on several fronts. You can have a technology that you've demonstrated through clinical or preclinical studies, but then for medical applications you've got to go through the whole regulatory process, and that adds significant time.
People say that nanobots will never happen. I think they will and that the process of getting there will add to our understanding and knowledge of medicine.
What are the implications of nanomedicine for pharmaceutical and biotechnology companies?
It's happening, and if you're a pharmaceutical or biotech company you need to know about it. Pharmaceutical companies have put a lot of drugs on the shelf because they didn't pass solubility tests. If you could put a drug inside a nanoparticle you might overcome solubility problems. You wouldn't have to keep making new drugs because you've got this whole closet full of ones that you've put aside.
And if you could target delivery, it's likely that you could overcome toxicity issues. Wouldn't it be great if when you're trying to do a cardiac drug you don't have to worry about kidney or liver toxicity? That's the promise of nanomedicine. It remains to be seen how much of the promise gets delivered.
• Cecilia Haberzettl, founder and president of TechnoMed Strategic Partners, recently wrote a paper on nanomedicine in Nanotechnology. You can contact her at firstname.lastname@example.org.
About the author
Liz Kalaugher is editor of nanotechweb.org.