Using a combination of polymers that respond to temperature, a research team at the University of Utah has developed a multifunctional nanoparticle that can image tumors using ultrasound and simultaneously deliver cell-damaging energy and anticancer drugs to those tumors. In addition, these nanoparticles appear to act specifically on tumors and not on healthy tissue.
Reporting its work in the journal Ultrasonics, a research team headed by Natalya Rapoport, D.Sc., describes its development of nanoparticles designed to turn into larger microscale bubbles at body temperature. These nanoparticles are made of perfluorocarbons, which interact strongly with ultrasound, and small amounts of two different biocompatible polymers derived from poly(ethyleneglycol) (PEG). By adjusting the relative amounts of the two PEG-based polymers, the investigators found that they could create nanoparticles that were stable at room temperature but that at body temperature would eventually combine to create ultrasound-responsive microbubbles. The researchers also demonstrated that they could load therapeutic doses of doxorubicin, a potent anticancer drug, into these nanoparticles and that the drug remained entrapped when the transition from nanoparticles to microbubbles occurred.