University of Pennsylvania Researchers Develop "Onion" Vesicle Drug Delivery System

Researchers at the University of Pennsylvania have announced that they have developed “onion” shaped vesicles for drug delivery. A vesicle is a membrane structure that is used to keep each cell’s DNA and proteins safe from damage and toxins. The UP researchers have developed a kind of dendrimer, which is a molecule that has “tree like” branches. The dendrimers allowed the research team to determine the diameter and thickness of their vesicles, and they were designed to self-assemble with layers of membranes similar to what one would see with an onion.

Because researchers can control the number of layers and the diameter of the dendrimers, they can also release drugs over longer periods of time, or release a new dose — or a even a cocktail of drugs in a sequence— with each layer. The concept could be valuable for pharmaceutical companies looking for efficient drug delivery systems for clinical drug development projects.

The study was published in the Proceedings of the National Academy of Sciences journal, and was headed by Virgil Percec, a professor in UP’s Department of Chemistry. Percec talked about some of the results of his research. “The problem is that once you remove the proteins and the other elements of a real biological membrane, they are unstable and don't last for a long time. It's also hard to control their permeability and their polydispersity, which is how close together in size they are. The methodologies for producing them are also complicated and expensive.”

Percec added that the dendrimer structures have helped the researchers to find a more stable drug delivery method. He noted that the structures’ ability to self-assemble made them that much more useful in research and development settings, especially since the researchers can control the number of layers and the drugs contained.