Light-Activatable Theranostic Agents for Image-Monitored Controlled Drug Delivery.

A novel drug delivery vehicle using nanodroplets activated by light irradiation for drug release in a controlled manner has been developed. Drug encapsulated in the nanodroplets was released upon the phase-transition from liquid droplet-to-microbubbles (vaporization) by plasmonic photothermal heat from gold nanorods adsorbed on the surface of the nanodroplets. The nanodroplets were stable against aggregation and dissolution at 4 ºC over 3 months to date. The phase-transition was quantitatively analyzed by ultrasound imaging to examine the amount of drug release non-invasively. In vitro studies showed that cell death occurred only when light irradiation was performed with the drug-encapsulated nanodroplets. Ex vivo studies demonstrated a potential application of the nanodroplets for treating posterior eye diseases. Thus, it has been demonstrated that our gold nanorod-coated light-activatable nanodroplets can be a candidate for a controlled release and a dosage-monitored drug delivery system.