Módulo Mini Blot

For proteins larger than 100 kDa, we recommend pre-equilibrating the gel in 2X NuPAGE Transfer buffer (without methanol) containing 0.02-0.04% SDS for 10 minutes before assembling the sandwich and then transferring using 1X NuPAGE transfer buffer containing methanol and 0.01% SDS.

Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.

Here are possible causes and solutions:

- Presence of air bubbles between the gel and the membrane preventing the transfer of proteins. Be sure to remove all air bubbles between the gel and membrane by rolling a glass pipette over the membrane surface.
- Expired or creased membranes used. Use fresh, undamaged membranes.

Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.

The swirling and diffuse banding patterns are typical of molecules moving laterally before binding to the membrane during transfer. Here are possible causes and solutions:

- Poor contact between the gel and the membrane: The gel should be attached to the membrane through capillary action. To ensure that this happens, make sure that you roll over the surface of each layer of the gel/membrane sandwich with a glass pipette to ensure good contact between the gel and the membrane. It is helpful to use a disposable pipette to place some extra transfer buffer on the surface of each layer as the sandwich is being made. Also, the pads need to be fully saturated (push down with gloved hand when they are placed in transfer buffer to make sure there are no air bubbles.)
- Under-compression of the gel: The gel/membrane assembly should be held securely between the two halves of the blot module. Try adding another pad or replace any pads that have lost their resiliency with fresh ones.
- Over-compression of the gel: A good indication of over-compression is if the gel has been excessively flattened. In the event that the sandwich is over-compressed, remove enough pads so that the blotter can be closed without exerting excess pressure on the gel and membrane.
Note: The height of the uncompressed pads should be 0.5-1.0 cm above the level of the sealing gasket.

Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.

Here are possible causes and solutions:

- High ionic strength of the transfer buffer. Prepare the buffer as described in the manual.
- Power supply is operating at a current close to the current limit of the power supply. Use a power supply with higher limits.

Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.

Here are possible causes and solutions:

- Too short a transfer time: Increase the blotting time by 15 minute increments.
- Inappropriate gel type: Check the percentage of the gel used and switch to a higher percentage gel.
- Inappropriate amount of SDS: Add 0.01-0.02% SDS to the transfer buffer to facilitate migration of the protein out of the gel.
- Inappropriate methanol content: Decrease the amount of methanol in the transfer buffer.
Note: Higher molecular weight proteins usually do not transfer completely as compared to mid to low molecular weight proteins.

Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.