One advantage of a DNA tether is that its melting point is tunable. Longer strands and differently coded strands require different amounts of heat to break. This heat-sensitive tuneability makes it possible for a single particle to simultaneously carry many different types of cargo, each of which can be released at different times or in various combinations by applying different frequencies or durations of electromagnetic pulses.
To test the particles, the researchers implanted mice with a tumor-like gel saturated with nanoparticles. They placed the implanted mouse into the well of a cup-shaped electrical coil and activated the magnetic pulse. The results confirm that without the pulse, the tethers remain unbroken. With the pulse, the tethers break and release the drugs into the surrounding tissue.
The experiment is a proof of principal demonstrating a safe and effective means of tunable remote activation. However, work remains to be done before such therapies become viable in the clinic.
To heat the region, for example, a critical mass of injected particles must clump together inside the tumor. The team is still working to make intravenously injected particles clump effectively enough to achieve this critical mass.
Our overall goal is to create multifunctional nanoparticles that home to a tumor, accumulate, and provide customizable remotely activated drug delivery right at the site of the disease, said Bhatia.
|Contact: Elizabeth Thomson|
Massachusetts Institute of Technology