Bio-Rad Helios® Gene Gun System - Manual (Page 47)

3. Raise the arm up and away from the base.
4. The Tubing Cutter may be cleaned with soap and water and /or with 70% or 100% ethanol.
Do not autoclave the Tubing Cutter.
5. Assembly is the reverse of disassembly. With the spring in place, lay the cutting arm, correctly
oriented, on top of the base. With the index and middle fingers of your left hand, press down
on the left side of the arm to compress the spring about 3/16”. Simultaneously, with the index
and middle fingers of your right hand, push the arm to the left to engage the cutting arm
under the stainless steel pivot pin on the left side of the base and under the stainless steel
retaining pin on the right side of the base.
10.5 Cleaning and Sterilizing the Helios Gene Gun
In situations where sterility is a concern, such as in vitro targeting, the spacer may be
brought as close to the target surface as possible without actually touching the surface.
Alternatively, by wiping down the end of the barrel liner with 70% alcohol or dilute bleach
followed by a rinse with distilled water, the spacer may touch the target surface.
It is possible to sterilize certain parts of the instrument by autoclaving. The following
parts may be autoclaved:
Barrel liner
Cartridge holder
Cartridge extractor tool
The following items should never be autoclaved or imersed in liquid:
Gene Gun
Tubing Prep Station
Helium Regulator
These parts, along with the Tubing Cutter, may be cleaned using a cloth and a mild soap
solution. Do not autoclave the Tubing Cutter.
Although Gold-Coat tubing may be autoclaved, this is not recommended since it may
result in water condensation inside the tubing which will lead to poor quality cartridges.
10.6 Testing Cartridges for Microcarrier Penetration and Density
(Optional)
Either of these procedures may be used to roughly determine the quality of the cartridge
preparation. These procedures give only qualitative results and are therefore best when they
can be compared against cartridges that have been shown to produce positive results in a bio-
logical assay. The results are very dependent on the size of the microcarriers and on the amount
of PVP used in loading the microcarriers into the Gold-Coat tubing.
Fig. 25. Representative bombardment showing penetration of 1.6 µ gold particles into Parafilm at
(left to right) 100, 200, 300, 400, 500, and 600 psi using the Helios Gene Gun.
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