Skip to main content
. Author manuscript; available in PMC: 2009 Mar 2.
Published in final edited form as: Nat Protoc. 2006;1(3):1517–1521. doi: 10.1038/nprot.2006.258

Figure 1.

Figure 1

Helios gene gun with the original accelerator chamber and associated spacer (boxed, and its replacement in the modified version). The spacer defines the minimum distance between the target and the accelerator channel cone. The cone is designed to spread the gold/DNA particles superficially over a wide area. The modified chamber is shown in the inset. The spacer has been eliminated, and the cone-shaped barrel is replaced with an external barrel with a reduced diameter. This allows deeper tissue penetration at lower gas pressures over a reduced area16.