You may very well have prepared a nearly perfect gel, and would have a difficult time improving upon the product. If that is so, then by all means gloat about it! If you didn't do such a hot job don't despair. All good scientists learn from their mistakes, in fact, without making mistakes most of us wouldn't learn much at all!
The "Hall of Shame" presents examples of some of the worst gels students (and instructor) have run in past labs, with an example or two from a research lab. They represent many of the ways one can mess up a gel (but not all of them - we're still finding new ways!). See what features of your own gel(s) were unsatisfactory - or at least less than perfect - and use the illustrations to figure out what you might do to improve your technique.
To critique your own work identify your symptoms and use the gallery to select appropriate example(s). Each example is linked to a full sized image with suggessted explanations for the symptoms. From this "hall of shame" you should be able to determine what can be done to correct the problem(s). If you wish you may browse by descriptions of symptoms, listed below the gallery.
Symptoms 1—Smears
Smeared gels – example 1
Smearing can have a variety of causes, but most commonly it is due to an unevenly poured acrylamide mixture or due to gross overloading of protein.
In this example the gel was not properly poured, so that the lower half had begun to polymerize before the upper part was poured. The first gel mix began to polymerize too quickly. Rather than prepare a new gel cassette, the students simply stopped pouring, prepared a new mix, and poured it on top of the old. Obviously, the bond wasn't particularly good.
Smeared gels – example 2
In this example a lot of protein was loaded in each of the wells, all the way across. Most of the lanes can still be interpreted, but smearing is particularly evident in lanes 3 and 4. Those lanes contained primarily one protein (hemoglobin subunit), as did lanes 9 and 10. However, the group that loaded 3 and 4 underestimated the protein concentrations in their red cell lysate and red cell cytoplasm fractions. Those fractions contained so much protein that samples had to be diluted prior to preparing a protein assay tube. The students forgot to take the dilution factor into consideration when determining protein concentration.
The capacity of a mini-gel for a mixed protein sample is 20 to 40 micrograms/well, depending on the resolution needed and number individual polypeptides in the mix. However, if a pure protein is loaded, one single band will contain all 20-40 micrograms, and the result is a mess.
Smeared gels – example 3
Here is another example of gross overloading, and it appears these students made the same mistake as in example 2. It looks as though there was some inconsistency in the gel also.
