September 26, 2006 at 4:59 pm (Sam's Posts)

The majority of the information gathering in my head the past couple weeks has been directly related to my research project. I am reading a cool book entitled Blood: An Epic History of Medicine and Commerce, but for now I am going to talk about what I am doing in the lab. I know that the theory behind the project is not front end global health, but as Sarah thankfully reminds me, there is lab research behind every product that goes out into the world to improve lives, and that makes me feel useful.

I have repeated the gist of my work multiple times to friends and family since I’ve started, and I’m getting better and better at it. I think my explanation can now be called ‘functional’, although there is still much room for improvement. The big picture is this: DNA tells the cell which proteins to build. The proteins do the cell’s (and thus the body’s) work. If your body’s not working correctly, there probably is something wrong with the DNA in addition to the proteins. So scientists think many diseases announce themselves through changes in DNA sequences. If we can fully identify the DNA content in a given sample, then we can compare DNA in diseased cells and normal cells and figure out which DNA sequences are responsible for the disease.

So the challenge lies in knowing the exact DNA content of a sample. We figure out what’s in a sample by mixing it with a probe that is complementary to only one specific DNA sequence. Only DNA that has a code complementary to the probe will bind to that probe. If we label the sample DNA beforehand, either with magnetic beads, or radioactive particles, or with molecules that can fluoresce, then we can measure magnetic field, radioactivity, or light emission, respectively, in order to know how much of a certain DNA sequence is in the sample.

I don’t do any of that.

What I do is figure out how we can raise the detection limit of the DNA analysis. The more fluorescent molecules you can bind to a piece of DNA, the brighter the light will be and the easier it will be to detect. This is where nanotubes come in; we think we can load a whole boatload of light-emitting molecules onto a nanotube and use it as a label. Then even if only a couple copies of a certain DNA sequence are present, we might still be able to detect it. And that gets us closer to knowing exactly what’s in the DNA and thus what’s causing the disease.

So it’s pretty far removed from widescale disease prevention. But it’s something. I’m thinking about the eventual arrival of a cheap and straightforward mechanism for rapid, full analysis of ones DNA. You know, one that can be done every year for every patient, just take a sample, toss it into a DNA purifier, throw it onto a chip with thousands of probes, and then slide it into a luminometer to measure the light and figure out what’s there and how much of it there is. I think some people are calling it a “lab-on-a-chip”. That would be pretty amazing.

I wonder what infectious disease research is like. Ideally I’d feel closer to the need, and to the actual advent of a technology. i guess I’ll take what I got right now though. It’s a good start.


1 Comment

  1. msoule said,

    I think that the work you’re doing is amazing. Improvements in labelling are incredibly important and useful on a very basic level. The ability to treat is based on the ability to detect what needs treatment. Advances in lab detection methods increase the ability to detect and thus the ability to treat. You aren’t far off from the treatment level of things, my friend. If you were looking at the role of certain proteins or transcription factors, that would be a little farther removed, but you’re designing lab technology that practitioners will use directly. If what you’re working on works out (which I hope it does), the effects on global health will ripple outwards. As the technology gets more widespread, it’ll get more advanced and also less costly, so labs in needy places may ultimately be touched by your work. Thus, I think, the biotech people do more than they can immediately see, but they really do a lot. Rock on!

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