Ultrasound-Guided Nanodroplets Enable Precision Drug Delivery
Researchers have found a way to deliver drugs precisely where they’re needed in the body. The method uses ultrasound waves to trigger the release of drugs from tiny carriers circulating in the bloodstream. This targeted approach could dramatically reduce side effects by lowering the total dose required.
The carriers are nanoscale droplets, less than 1/200th the width of a human hair. They have a hollow outer shell made of polymer molecules surrounding an inner core of oily perfluorocarbon liquid mixed with the drug. The shell keeps the droplets separate and shields them from the immune system.
Ultrasound Activates Drug Release
To release the drug, the researchers use an ultrasound beam focused on the target area. The sound waves cause the perfluorocarbons to expand, stretching the droplet’s shell and allowing the drug to diffuse out. The beam can be steered in 3D to pinpoint delivery to a region just a few millimeters across.
The team tested the efficiency of drug release for three different perfluorocarbons. They found that perfluorooctylbromide (PFOB), which has a high boiling point of 142°C, provided the best balance of droplet stability and release efficiency when activated by low-frequency 300 kHz ultrasound.
Animal testing in a macaque monkey showed the PFOB nanodroplets were well-tolerated over six weekly doses, with no detectable side effects based on blood markers of liver, kidney, and immune function. The research protocol has been published openly so other groups can build on the findings.
The researchers believe this method could be applied to deliver drugs for a wide range of conditions. Psychiatric applications are one exciting possibility. According to study leader Dr. Jan Kubanek, “Localized delivery of propofol could be used as a diagnostic tool to identify brain regions causally involved in disorders for individual patients. For more lasting treatment, ketamine delivery could be a potent method to rewire neural circuits.”
The next step will be to replicate the safety results in human trials. If successful, this innovative delivery system could enable lower-dose, precision-targeted therapies for numerous diseases.
