As the particular GPCR the team worked with was an olfactory receptor, the test case for their nanotube device was to function as sensor for airborne chemicals.
"If there's something in the atmosphere that wants to bind to this molecule, the signal we get through the nanotube is about what fraction of the time is something bound or not. That means we can get a contiguous read out that's indicative of the concentration of the molecule in the air," Johnson said.
While one could imagine scaling up these nanotube devices into a synthetic nose making one for each of the approximately 350 olfactory GPCRs in a human nose, or the 1,000 found in a dog's Johnson thinks that medical applications are much closer to being realized.
"GPCRs are common drug targets," he said. "Since they are known to be very important in cell-environment interactions, they're very important in respect to disease pathology. In that respect, we now have a pathway into interrogating what those GPCRs actually respond to. You can imagine building a chip with many of these devices, each with different GPCRs, and exposing them all at once to various drugs to see which is effective at triggering a response."
Figuring out what kinds of drugs bind most effectively to GPCRs is important because pathogens often attack through those receptors as well. The better a harmless chemical attaches to a relevant GPCR, the better it is at blocking the disease.
The Penn team also made a technical advancement in stabilizing GPCRs for future research.
"In the past, if you take a protein out of a cell and put it onto a device, it might last for a day. But here, we embedded it in a nanoscale artificial cell membrane, which is called a nanodisc," Johnson said. "When we did that, they lasted for two and half months, instead of a day."
Increasing the lifespans of such devices could be beneficial to t
|Contact: Evan Lerner|
University of Pennsylvania