Band smearing / streaking (Western Blot)

Question

Accepted Answer

Bands have blurred edges, show vertical smearing or the entire lane is hazy; background is fogged, making band intensity comparisons unreliable. Common causes: 1) Loading amount was too high (sample overloaded) 2) Sample was degraded; lysate contains too much salt or nucleic acid 3) Protein was not fully denatured or reduced before loading 4) Gel percentage was wrong, or electrophoresis overheated Solutions: 1) Reduce loading amount; run a loading-gradient pilot first 2) Spin lysate thoroughly post-lysis and add protease inhibitor; treat with DNase if viscous 3) Add SDS sample buffer correctly and boil 5–10 min 4) Choose appropriate gel percentage; lower voltage and avoid overheating during electrophoresis