Bio-Rad Mini Trans-Blot® Cell - Manual (Page 30)

24 Mini-Trans-Blot Electrophoretic Transfer Cell
Swirls or missing bands; diffuse transfers
1. Poor contact between the membrane and the gel. Air
bubbles or excess buffer remain between the blot and
gel.
• Use a test tube or pipet as a rolling pin, and roll
over the membrane carefully in both directions
until air bubbles and excess buffer are removed
from between gel and membrane, and complete
contact is established
• Use thicker filter paper in the gel/membrane
sandwich
• Replace the fiber pads. Pads will compress with
time, and will not hold the membrane to the gel
2. Power conditions are too high.
• Always check the current at the beginning
of the run. The current may be too high for a
particular voltage setting. If the buffer is prepared
improperly, the conductivity may be too high,
resulting in excessive power delivered to the cell.
See the power guidelines for specific applications
in Section 3
3. The membrane is not properly wet or has dried out.
• White spots on the nitrocellulose membrane
indicate dry areas where protein will not bind. If
wetting does not occur immediately by immersion
of the sheet in transfer buffer, heat distilled water
until just under the boiling point, and soak the
membrane until completely wet. Equilibrate in
transfer buffer until ready for use
• Because of the hydrophobic nature of PVDF, the
membrane must be prewet in methanol prior to
equilibration in aqueous transfer buffer. Do not let
membrane dry after wetting. Rewet in methanol if
necessary