Drug delivery is a crucial area of medical research and technology that more so than other fields must take convenience into account. As an example, pills are often preferable to injections because patients are more likely to comply with the former than the latter. There has been a lot of excitement about needle-free injection systems, nasal sprays, and transdermal patches – to name a few – but the holy grail of drug delivery is to fully restore and not just to replace. That is, the ideal system would empower the body to produce the needed drug endogenously. Genetic engineering is one such approach that still has a long way to go even with encouraging successes with diseases like hemophilia.
Reporting in Science, a team of researchers from the Rockefeller University has devised one of the more interesting approaches to drug delivery that we’ve seen in some time. Essentially, they combined tools from genetic engineering and nanotechnology to create “remote-controlled genes.” They took advantage of the fact that cells have many types of membrane channels that respond to different stimuli (e.g. voltage, concentration, etc). One such channel, TRPV1 (aka the capsaicin receptor), responds to temperature and opens up around 42 degrees Celsius, thus allowing calcium to rush into the cell. The genetic engineering aspect of the team’s work was in the modification of this receptor as well as the modification of the downstream path so that the influx of calcium would lead to increased insulin production.
But how did they get the TRPV1 channels selectively heated without harming neighboring cells? Enter iron oxide nanoparticles. These particles were conjugated to antibodies that selectively bind to the TRPV1 channel. When stimulated by low-frequency radio waves, the nanoparticles heated up, thus opening the TRPV1 channels and leading to the production of insulin. Though the experiments worked, the team’s principal investigator noted that
his team did not develop the method as a way of managing diabetes; insulin and blood sugar levels simply provide convenient physiological readouts for checking that the remote control is working. “There are many good treatments for diabetes that are much simpler,” he says. However, the system could potentially be engineered to produce proteins to treat other conditions.
Let’s just hope that if this becomes a reality, the ubiquitously present electromagnetic radiation would not inadvertently (or maliciously) cause the release of such drugs.
More at Nature News: Remote-controlled genes trigger insulin production…