A new study published in the journal Proceedings of the National Academy of Sciences suggests a novel way to locally deliver chemotherapy drugs as and when needed rather than using the current drug delivery systems that release a constant dose of the drug over time.
Led by David J. Mooney, Ph.D., a Core Faculty member at Harvard's Wyss Institute for Biologically Inspired Engineering and the Robert P. Pinkas Family Professor of Bioengineering at the Harvard School of Engineering and Applied Sciences (SEAS), the team loaded a biocompatible hydrogel with a chemotherapy drug and used ultrasound to trigger the gel to release the drug.
Like many other injectable gels that have been used for drug delivery for decades, this one gradually releases a low level of the drug by diffusion over time. To temporarily increase doses of drug, scientists had previously applied ultrasound -- but that approach was a one-shot deal as the ultrasound was used to destroy those gels.
This gel was different. The team used ultrasound to temporarily disrupt the gel such that it released short, high-dose bursts of the drug - akin to opening up a floodgate. But when they stopped the ultrasound, the hydrogels self-healed. By closing back up, they were ready to go for the next "on demand" drug burst - providing an innovative way to administer drugs with a far greater level of control than possible before. That's not all. The team also demonstrated in lab cultures and in mice with breast cancer tumors that the pulsed, ultrasound-triggered hydrogel approach to drug delivery was more effective at stopping the growth of tumor cells than traditional, sustained-release drug therapy. "Our approach counters the whole idea of sustained drug release, and offers a double whammy," said Mooney. "We have shown that we can use the hydrogels repeatedly and turn the drug pulses on and off at will, and that the drug bursts in concert with the baseline low-level drug delivery seems to be particularly effective in killing cancer cells."