Biomedical engineering researchers have developed an anti-cancer drug delivery method that essentially smuggles the drug into a cancer cell before triggering its release. The method can be likened to keeping a cancer-killing bomb and its detonator separate until they are inside a cancer cell, where they then combine to destroy the cell.
"This is an efficient, fast-acting way of delivering drugs to cancer cells and triggering cell death," says Dr. Ran Mo, lead author of a paper on the work and a postdoctoral researcher in the joint biomedical engineering program at North Carolina State University and the University of North Carolina at Chapel Hill. "We also used lipid-based nanocapsules that are already in use for clinical applications, making it closer to use in the real world."
The technique uses nanoscale lipid-based capsules, or liposomes, to deliver both the drug and the release mechanism into cancer cells. One set of liposomes contains adenosine-5'-triphosphate (ATP), the so-called "energy molecule." A second set of liposomes contains an anti-cancer drug called doxorubicin (Dox) that is embedded in a complex of DNA molecules. When the DNA molecules come into contact with high levels of ATP, they unfold and release the Dox. The surface of the liposomes is integrated with positively charged lipids or peptides, which act as corkscrews to introduce the liposomes into cancer cells.
Meanwhile, two other things are happening simultaneously. First, the ATP liposomes spill their ATP into the Dox liposomes, releasing the Dox from its DNA cage. Second, the walls of the Dox liposomes create an opening in the endosome, spilling their Dox-rich contents into the surrounding cell -- leading to cell death.
"This work is somewhat similar to previous research we've done with polymer-based nanogels -- but there is a key difference," says Dr. Zhen Gu, senior author of the paper and an assistant professor in the joint biomedical engineering program. "The difference is that this liposome-based technique allows us to introduce additional ATP into the cancer cell, releasing the drug more quickly.
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