By delivering chemotherapeutic messages in nanoscale bottles, researchers at Georgia Institute of Technology and Shandong University, China, seek to target cancer cells without impacting healthy tissue. The tiny silica Scanning electron microscopy image of nanocapsules formed after removal of the gold nanoparticles and polystyrene beads, leaving behind an opening that can be used to fill the capsules with a payload. Source: Jichuan Qiu/Georgia Institute of Technologyspheres are engineered for released control of drugs in specific parts of the body.

The 200 nm-wide biocompatible vials encapsulate a chemotherapy payload, fatty acids functioning as phase-change materials and a near-infrared dye. To release the medicine, a near-infrared laser is directed toward the device, allowing the temperature-sensitive dye to heat up and cause the fatty acids to melt. The chemo drug then exits through a small opening in the sphere to achieve both stable dispersion and controllable release.

To fabricate the drug delivery devices, polystyrene spheres with an embedded gold nanoparticle are coated with a silica material. Removal of the polystyrene and gold leaves hollow silica spheres with a small opening, the size of which can be tweaked by using bigger or smaller gold particles. The release profile can be controlled by varying the size of the hole and/or the duration of laser irradiation.