The function of biological molecules is inherent in their structure. The most famous example of this is genomic DNA, made up of extravegant sequences of nucleotides, which are used as a template to create RNA- the instruction manual for building all the proteins used in your cells. But, there are far more examples, as well. For instance, some proteins called transcription factors attach to DNA at specific spots and act as a "switch" to turn on (activate) or off (repress) the production of other important molecules. The presence or absence of these proteins on the DNA can be indicators for a wide variety of disease, including various forms of cancer.
In our lab, we are using a new system called solid-state nanopores to gain insight into the fine structure of molecules on an individual basis. The concept of this system is simple: a small (nanometer scale) hole is formed in a thin membrane, which is then used as a barrier between two basins of salt solution. When a voltage is applied across the membrane, a strong electrical field is created through the fabricated hole, resulting in a measurable ionic current. By placing charged molecules (like DNA) on one side of the membrane, the electric field is able to pull the molecules through the hole one at a time and on to the opposite side. When this happens, the temporary presence of the molecule inside the hole blocks the measured ionic current by a certain amount that is related to the size of the molecule (see figure at left).
We are working to expand this measurement platform to allow the detection of local structures along a single molecule and their relative positions. Imagine a device that could tell you whether you are prone to a specific type of disease, allowing the earliest possible preventative care. Or, even more intriguing, imagine the ability to have your own personal genome sequenced. We believe this is the future of medicine and strive to make it a reality through nanotechnology.
You can find out more about these efforts at our publications page, or by contacting Adam.