A study published by researchers at the Georgia Institute of Technology reports that silica bottles filled with medicine and a temperature-sensitive material could be used for drug delivery to kill malignant cells in certain parts of the body.
The research team created silica-based hollow spheres, 200 nanometers in size, each containing a small hole in the surface. According to a spokesperson for Georgia Tech, the size of the tiny silica bottles is “five-hundredth of the diameter of a hair.”
The spheres are capable of holding a range of payloads that could be released at specific temperatures.
Fatty acids, near-infrared dye, and anticancer drugs are packed inside the spheres, with an infrared laser, which is absorbed by the dye, used to quickly melt the fatty acids in the sphere and thereby release the therapeutic drug into the body. Without the use of the laser, the medicine remained encapsulated.
Jichuan Qui, a postdoctoral fellow in the Xia group that conducted this study, stated, “This controlled release system enables us to deal with the adverse impacts associated with most chemotherapeutics by only releasing the drug at a dosage above the toxic level inside the diseased site.”
The Georgia Tech spokesperson explained that chemotherapy causes side effects as the drugs travel throughout the body and kills normal, healthy cells, in addition to cancer cells. The tiny bottle system enables the drug to be released at a dosage above the toxic level but only once inside the diseased site therefore not affecting healthy cells.
“This approach holds great promise for medical applications that require drugs to be released in a controlled fashion and has advantages over other methods of controlled drug release,” Qui said.
According to the researcher’s findings, the size of the hole in the sphere could be changed to enable nanocapsules to release payloads at different rates.
The spheres are fabricated out of polystyrene with a small gold nanoparticle embedded in the surface and then coated with a silica-based material covering everything but the embedded gold nanoparticle. The gold and polysytyrene are then removed, leaving a hollow silica sphere with a small opening that could be used for this type of delivery.
To load the spheres with each individual payload, the bottle was soaked in a solution containing the mixture, removing any trapped air, and washing away excess material and payload with water. As a result, the nanocapsules contained an even mixture of temperature-sensitive material, the therapeutic, and the near-infrared dye.
