The Tiniest Doctors Have Arrived

Technology is making everything smaller and smarter these days, it seems – from cellphones and cars to computers and cameras. It makes sense that scientists would look for a way to make medicine smaller and more technologically advanced, too.

Imagine receiving a vaccine, taking an inhaler, or applying a topical cream that would release nano-sized particles specifically designed to seek out and stop cells harming the body. With the help of nanotechnology, scientists are well on their way to engineering new ways to study, diagnose, treat, and prevent both common medical conditions, as well as some of the leading causes of death.

“The beauty of the nanomedicine component is you're not only creating and designing what is potentially a very potent therapeutic … but you're also overcoming the delivery problem in some cases,” says Dr. Chad Mirkin, a chemistry professor at Northwestern University, and a member of the President's Council of Advisors on Science and Technology (PCAST).

Nanomedicine – the application of tailored nanotechnology in a healthcare setting – though still in its infancy, has particularly taken off within the last decade. Scientists across the world are branching off in new directions to use nanomedicine to treat a range of different conditions, from cardiovascular and pulmonary diseases (such as COPD) to psoriasis, diabetes, and even cancer.

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“With the Human Genome Project and all the different pathways that regulate how we function, we have an enormous number of targets we could go after,” Mirkin says of the possibilities for nanomedicine to expand.

The ability to restructure nanoparticles also gives them a sort of multifunctionality that wasn’t possible before.

“To particularize things such that they're efficiently delivering medicines or antigens or adjuvants, that's really what nano is able to do for us,” says Joseph DeSimone, a chemistry professor at the University of North Carolina at Chapel Hill and a recipient of the National Medal of Technology and Innovation.

Just over 10 years ago, DeSimone founded a company – Liquidia Technologies – that has been building on his work in nanomedicine. DeSimone’s work has primarily focused on three areas: developing nanoparticles used in inhalable therapeutics, those used in vaccines, and nanoparticles that could be used to treat cancer. The inhalable therapeutics could be used to treat major ailments of the airway, such as pulmonary hypertension (high blood pressure that affects the lungs and heart), and COPD (lung diseases that make it difficult to breathe).

In the area of vaccines, DeSimone and his colleagues have benefitted from working at the same scale as the virus, “nature’s vehicle for delivery.”

“You have to work at this length scale if you want to be able to efficiently deliver things,” DeSimone says.

DeSimone and his colleagues have been developing nanoparticles that are meant to stimulate the immune system to help people respond to infectious diseases like influenza, dengue (a viral infection transmitted by mosquitos), and even Zika.

While the vaccines for Zika and dengue are still in pre-clinical trial stages, several others (such as the flu vaccine) are in clinical trials, and could begin being released more widely in the next two to three years, DeSimone says.

DeSimone’s technology can also be used to engineer nanoparticles that can stimulate the immune system to respond to cancer.

With these nanoparticles, DeSimone says two substances to stimulate an immune system response: antigens (any foreign substance that prompts the production of antibodies) and adjuvants (a substance that enhances an immune response). Together, this helps certain cells more efficiently stimulate T-cell responses.

Mostafa El-Sayed,  a chemistry professor at the Georgia Institute of Technology and a recipient of the National Medal of Science, has also used nanotechnology in medicine to develop an alternative treatment for cancer. By delivering gold nanorods to cancer cells, El-Sayed’s treatment stops the cells from multiplying, and makes them easier to detect. And because the gold nanoparticles absorb light quickly, converting it to heat, the cells could be selectively killed by shining a light on them.

“Previously, we've shown that we can bring gold nanoparticles into cancer cells and by shining a light on them, can kill the cells,” El-Sayed said in an interview with the Journal of the American Cancer Society. “Now we've shown that if we direct those gold nanoparticles into the nucleus, we can kill the cancer cells that are in spots we can't hit with the light.”

Despite the wide range of possibilities for the ailments that could be treated with nanomedicine, there are still some skeptics – and ethical questions that have risen with the growth of nanomedicine. For example, some simply wonder whether the chemical composition of certain nanoparticles could have a negative toxic effect on the body. To ease those concerns, scientists like DeSimone have been working to make nanoparticles biodegradable and biocompatible. And Mirkin and his colleagues have shown that spherical nucleic acids – DNA and RNA – are naturally and actively taken up by cells, eliminating the concern for toxicity.

But other critics have questioned whether nanomedicine could open the door to unnecessary human enhancements, rather than just the treatment of disease and chronic medical conditions.

“The potential impact of nanomedicine on society is expected to be huge as the nanopharma market grows significantly in the coming years. Given this backdrop, nanomedicine is poised to add a profound and complex set of ethical and societal questions,” Raj Bawa of Rensselaer Polytechnic Institute, wrote in a paper on ethical concerns with nanomedicine. “Some of these are recurring themes in bioethics while others will be discussed in slightly new ways due to nanomedicine's interdisciplinary nature: privacy, confidentiality, risks and benefits, defining disease, and enhancement.”

Still, DeSimone says it’s important to keep the bigger picture in mind and look for solutions, rather than letting concerns derail the good that could come from nanomedicine.

“You have to be careful of being afraid of the word ‘nano,’ as opposed to the chemistries that are being used in the nanoparticles,” DeSimone says.

Overall, people will want proof, Mirkin says.