Bio-Rad Helios® Gene Gun System - Manual (Page 26)

6. Remove the Gold-Coat tubing from the Tubing Prep Station. Turn off the flow of nitro-
gen to the Tubing Prep Station using the knob on the flowmeter.
7. From the dried Gold-Coat tubing cut a 29–30" (~75 cm) length of tubing for each 3 ml sam-
ple of Microcarrier/DNA suspension. (Note: Cutting the tubing with a scissors may distort
the shape of the end; the tubing may be easier to insert into the tubing support cylinder if the
end is subsequently cut in the tubing cutter.) Insert one end of the Gold-Coat tubing into the
end of the adaptor tubing fitted to the 10 cc syringe (see Section 4.3, step 5).
8. Vortex the microcarrier suspension and, if necessary, sonicate briefly to achieve an even
suspension of gold. Invert the tube several times to resuspend the gold; immediately
remove the cap and quickly draw the gold suspension into the Gold-Coat tubing approx-
imately 22–24", approximately 58 cm, (6–8" (~17 cm) from the end). AVOID DRAWING
BUBBLES INTO THE GOLD-COAT TUBING: Do not vortex the microcarrier sus-
pension while drawing it into the tubing. Do not try to remove all of the liquid from the
container with the suspension. Remove the tubing from the suspension and continue draw-
ing the suspension into the tubing another 2–3" (~6 cm) to leave some space at each end.
9. Immediately bring the Gold-Coat tubing to a horizontal position and slide the loaded
tube, with syringe attached, into the tubing support cylinder in the Tubing Prep Station
until the tubing passes through the O-ring.
10. Allow the microcarriers to settle for 3–5 min. Detach the Gold-Coat tubing from the adap-
tor tubing and attach to the tubing on the peristaltic pump or on the 10 cc syringe.
(Be careful not to rotate the Gold-Coat tubing.) Remove ethanol at the rate of 0.5–1.0"/sec
(this should require 30–45 sec).
11. Detach the peristaltic pump or syringe from the Gold-Coat tubing. Immediately turn the
Gold-Coat tubing 180° while in the groove and allow the gold to begin coating the inside
surface of the tubing for 3–4 sec.
12. Turn the switch on the Tubing Prep Station to ON ( I ) to start rotating the Tubing Prep
Station. (Warning: Keep objects away from the gears of the Tubing Prep Station while in
operation.)
13. Allow the gold to smear in the tube for 20–30 sec, then open the valve on the flowmeter
to allow 0.35–0.4 LPM of nitrogen to dry the Gold-Coat tubing, while it continues to rotate.
14. Continue drying the Gold-Coat tubing while turning for 3–5 min.
15. Turn the motor on the Tubing Prep Station to OFF (O). Turn off the nitrogen by closing
the valve on the flowmeter. Remove the tubing from the tubing support cylinder.
Preparing 0.5" Cartridges Using the Tubing Cutter
This procedure requires only a few minutes and should be performed as soon after load-
ing the DNA/microparticle suspension into the tubing as possible. It is important to store the
coated tubes in a desiccated environment. Tubes stored at 4 °C are stable for at least 8 months.
Materials
Supplied
Tubing Cutter
Razor blade
Cartridge storage vial
Desiccant pellets
To be Supplied by User
Gold-Coat tubing coated with microcarriers from Section 5.2
Scissors
Marking pen
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