If you show symptoms of strep throat, your doctor will swab your throat, send the sample to a lab to culture the bacteria, and wait for the results before writing a prescription. The day when a sick person can self-administer a blood sample and receive a diagnosis in minutes will see patients receiving treatment faster and clinical costs cut dramatically. That day may be within reach thanks to Dr. Shana Kelley, a professor in U of T’s faculties of pharmacy and medicine.
The Kelley lab is developing nanotechnology that could diagnose early stage cancer and other infectious diseases ten times earlier and at a fraction of the cost than is current clinical practice. Their project consists of an electronic chip the size of a dime containing complementary genetic material, or the appropriate antibodies, that could generate an electronic readout to inform doctors of a patient’s immediate health.
DNA and RNA are composed of nucleotide bases, adenine (A), guanine (G), cytosine (C) and thymine (T). Complementary base pairing occurs in double-stranded DNA helices between A and T and C and G, and mismatched, absent or damaged nucleotides can result in genetic mutations.
Kelley has been acknowledged as a frontier scientist worldwide in MIT’s Technology Review Top 100 Inventors, named an Alfred P. Sloan Fellow for her promising research career, and awarded the prestigious Pittsburgh Conference Achievement Award for “significant contributions to electrochemical biomolecular detection” in 2007. In 2008 she was named among Canada’s Top 40 Under 40 by Caldwell Partners. Last month The Varsity sat down with Dr. Kelley to discuss her new technology and whether it could revolutionize health care delivery.
The Varsity: What happens in cases where there is mutation of the genetic code in viruses or bacteria you are testing?
Shana Kelley: That’s a tricky thing to deal with. The solution is to look at many possibilities at one time. This is called multiplexing. Currently, we can look at 42 different sequences. If you have a virus you suspect can mutate in 42 different ways, you would be able to test them all. We could easily do 400 sequences by adjusting the patterning on the chip.
TV: To make this applicable for use in hospitals, will the industry need to synthesize different combinations of sequences for different diseases?
SK: Yes. Currently we’re developing this technology in my lab. The next step would be a very small company that would develop the technology further and eventually get it out to hospitals. It needs to be packaged into an instrument, something that a hospital worker can use very easily.
TV: How soon do you think this would be available to the public?
SK: Realistically, we have another year’s work to do to make sure our chips are sensitive enough and instrumentation easy to use. We’re hopeful that within that year we would transfer the technology into a company, and it would take another year to get the product to market. Ideally, we’re maybe two years away from getting something close to clinical use. My lab has been working on this stuff since 2000, and now we are in the final stretch of making it practical.
TV: What about the accuracy? Are there chances for false positives, where a test indicates a positive result that doesn’t actually exist?
SK: There’s always chances for false positives, false negatives even. Another reason multiplexing is so useful is that you are building controls right under your chip. You would put some sequences on there that shouldn’t be binding to anything in your sample, and if they are, you know that there is something wrong somewhere so you would put that test aside and do it again. It’s a similar concept with false negatives.
TV: The government would probably save a lot of money with patients occupying fewer beds for less time. Is the government funding this project, as well as private companies?
SK: Absolutely. We have funding from CIHR (Canadian Institutes of Health Research), NSERC (Natural Sciences and Engineering Research Council of Canada), OICR (Ontario Institute of Cancer Research), OCE (Ontario Centre for Excellence), and Genome Canada. Many agencies have been very generous and recognize the value of this in terms of the impact on quality of treatment and also in terms of the economics of the health care system.
TV: What led you to study nanotechnology?
SK: I was educated with a very interdisciplinary approach, where you think of an interesting problem and go out and learn about all the methods that you can use to solve it. As a graduate student, what I became interested in and remained interested in was developing new tools for clinical diagnostics. I knew a lot about prior efforts and why they failed, and what were really needed were new kinds of materials to serve as platforms for clinical diagnostics. It turned out that nanomaterials, which are the size of biological molecules, have a significant advantage as sensors. You can start to think about matching the size of your sensing element to the size of the thing you are looking for. It makes it a little bit less like looking for a needle in a haystack.
TV: Do you see yourself continuing to work with nanotechnology after the completion of this project?
SK: Sure. We’ve just written some proposals for using this type of technology for tuberculosis. It’s a huge problem in the developing world, as it’s very difficult to diagnose people in remote areas. The kind of instrumentation that we envision are chips that don’t require a lot of power. It can be very small because it doesn’t take much to read out the signals from these chips. That’s a whole new area for us. If you think outside the box and what challenges [doctors] face, we’ll always be finding new problems to solve [and] new application areas that will keep pushing us to do better science.
TV: How would you transfer information onto the chip in countries without the resources or laboratories ready to analyze the samples?
SK: We would basically have a unit the size of a blackberry. It would have one of the chips in it with an injection port for the sample. There would also be components embedded in there to burst open the bacteria, for example, and a readout would be shown to the person doing the test indicating the diagnosis. There is going to be a lot of difficult engineering going into making the device, but we know that we can do it based on the parameters. This could have a huge impact on a very large number of people.
TV: How long would the readout take?
SK: I think we can push it to give us a readout in a few minutes. We have seen that in experiments in our lab and we think that can be done with clinical samples as well.
TV: So the whole idea could apply to people at home, instead of going over to the hospital and spending time in the emergency room?
SK: Exactly. We may get there someday.
TV: Do you believe this a revolution?
SK: I think so. We now live in an era where we know the sequence of the human genome, we know about most of the proteins that operate in human cells, we know what genes predispose people to cancer, we know what the markers are. We just need the technology to be able to analyze them. If we can find that technology and adapt it in the right way, it could be a revolution. It would make clinical medicine very different to have access to the kinds of tools we are talking about.
