Figure 3.

Various approaches have been taken to lipid-based siRNA delivery. While some groups use rational design and focus on specific delivery aspects, such as lipid polymorphism leading to membrane fusion (A), others have employed high-throughput methods to screen through a wide array of different molecules to empirically determine the best structures (B–C). Reprinted by permission from Macmillan Publishers Ltd: Nature Biotechnology,^{86, 94} copyright (2010) (A) and copyright (2008) (B–C).