Ultrasound-Triggered Nanoparticles Deliver Drugs Precisely, Reduce Side Effects

Stanford Medicine researchers have developed a noninvasive drug delivery system that uses ultrasound and sugar-based nanoparticles to release medications precisely where they’re needed—potentially reducing side effects and improving treatment outcomes. This breakthrough, published in Nature Nanotechnology, could transform how drugs are administered for conditions ranging from chronic pain to psychiatric disorders.

The challenge with many medications is that they circulate throughout the body, affecting not only the target area but also healthy tissues. This can lead to unwanted side effects—such as nausea from painkillers, dissociation from psychiatric drugs, or damage to healthy cells during chemotherapy. The Stanford team’s solution is a system that encapsulates drugs in ultrasound-sensitive nanoparticles and releases them only when triggered by a focused ultrasound beam.

In their latest study, researchers demonstrated the system’s effectiveness in rats by delivering ketamine to specific regions of the brain and painkillers to targeted nerves in the limbs. The key innovation lies in the nanoparticle design. Unlike earlier versions that required complex chemicals and ultra-cold storage, the new formulation uses a simple 5% sucrose (sugar) solution. This makes the nanoparticles more stable, easier to produce, and safer for clinical use.

The nanoparticles travel through the bloodstream but remain intact until exposed to ultrasound. A narrow beam of ultrasound—applied externally—pinpoints the target tissue and triggers the release of the drug. This allows for millimeter-level precision, maximizing therapeutic effects while minimizing off-target impacts.

Dr. Raag Airan, senior author and assistant professor of radiology at Stanford, has been refining this concept for nearly a decade. Earlier iterations of the system showed promise but were limited by poor stability and low drug-loading capacity. The new sugar-based design overcomes these hurdles, making the technology more viable for real-world applications.