Bio-Rad Sequi-Gen GT Sequencing Cell - Manual (Page 19)

Note on Gel Bubble Formation
• The following injection times (from the bottom of IPC to the top) were found to result
in bubble-free gels: for 50 cm gels with 0.4 mm spacers, between 40–45 seconds; for
50 cm gels with 0.25 spacers, between 50–65 seconds. Injection times of 10 seconds
or less can result in bubble formation in the gel.
• Bubbles can form at the gel front because of soiled areas or uneven siliconization or
coating of the glass plates.
• To achieve bubble free gels, thoroughly clean both plates and siliconize the outer glass
plate before each use.
• If bubbles begin to form at the gel front, hard tapping on top of the IPC assembly
(above the bubble formation) while slowly injecting the gel solution should eliminate
the bubble. Alternatively, the comb end of the IPC assembly can be momentarily
lifted at an angle to facilitate elimination.
10. Continue to slowly inject the gel solution until the gel solution emerges a few centimeters
from the top of the notched (shorter) glass plate (across the entire width of the gel).
Important: If pouring a 38 x 50 cm IPC, remove the support that created an incline and
lay the unit level on the benchtop (use the Leveling Bubble provided). An additional 2 cm
support will be needed to level the IPC assembly. Some users find it convenient to use two
1.5 ml tube racks as props.
When the gel is past the short plate, lay the syringe on top of IPC assembly until gel
polymerization is complete. Do not remove the luer taper from the precision caster base
injection port, or the gel solution will drain out of the plates. Do not adjust the syringe
plunger after the gel has been cast (Figure 4.8).
11. Insert the comb(s) between the plates to the desired depth.
• If a sharkstooth comb is used, insert the flat edge of the comb no more than 5 mm past
the short glass plate.
• Clamp the comb(s) in place with three large metal binder clamps.
Fig. 4.8. Syringe position for gel polymerization.
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