For more than two decades, gene delivery has been accomplished by using engineered viruses as a vehicle to get into diseased cells and 70 percent of clinical trials worldwide continue to use this method. But, the viruses used for gene delivery occasionally evoke severe immune responses, so scientists continue to search for non-viral delivery vehicles.
Reporting in an article to appear in the March 29 print edition of the Journal of the American Chemical Society (published on-line on March 8), the authors describe the synthesis of the new lipid molecule.
Lipid DNA complexes are attracting increasing attention as non-viral DNA delivery vehicles. They have been described as one of the "hottest new technologies" for gene therapy, accounting for nearly 10 percent of ongoing clinical trials.
Lipids are molecules with two parts, a water-liking "headgroup" and oily tails that assemble together to avoid water. Lipids, along with carbohydrates and proteins, constitute the main structural material of living cells.
The novel lipid molecule created at UC Santa Barbara has a tree-shaped, nanoscale headgroup and displays unexpectedly superior DNA-delivery properties. "It generates a honeycomb phase of lipid DNA complexes," said Cyrus R. Safinya, a professor of materials; of molecular, cellular and developmental biology; and of physics at UCSB. The new molecule was synthesized in Safinya's laboratory by first author Kai K. Ewert, a synthetic chemist who is a project scientist in the research group.