Snap I.D. Protein Detection System From Millipore

Any researcher that works with proteins knows how tedious and time consuming running Western blots can be. Although the reagents involved have evolved over time, the basic protocol has remained the same. The Snap I.D. from Millipore has revolutionized this process, cutting the time it takes to do a Western blot from six hours to twenty-two minutes.

I usually run at least two protein gels a day for Western blots. The Snap I.D. is a very useful tool to detect proteins in less than half an hour after transfer. The system does have its downsides. For one, it does require the use of disposable blot holders. I have found that they are reusable, provided that it is for the same antibody, if the membrane is thoroughly washed with ddH₂O; however, I would not recommend using them more than three or four times. Another issue that we have encountered is that even a new blot holder may become clogged during the blocking step if the milk has not been dissolved properly. To prevent this from happening, make sure that the half percent milk solution has plenty of time to dissolve, at least an hour.

We have also had some issues with comparing relative concentrations of some proteins when using the Snap I.D., particularly when using a monoclonal antibody or low total protein concentrations. In those instances, the primary antibody incubation should be done using traditional methods. The blocking step, secondary antibody staining and washing steps can still be done on the Snap I.D., saving a total of two hours from the traditional protocol.

There is an upside to the lowered sensitivity that we have been noticing. On the Snap I.D. the amount of non-specific binding is greatly reduced. We have been able to get relatively dirty polyclonal antibodies to yield useful blots when the non-specific bands are relatively faint. Because of this lowered sensitivity, it is recommended that you use a two and a half times greater concentration of antibody in your buffer. This does not translate to a higher volume of antibody requirement because the total volume of buffer needed per mini blot is only three mls. Increasing the antibody concentration has not resulted in an increased sensitivity.

This system does allow for great versatility in the number of blots that can be simultaneously run. This makes it a great system for testing new antibodies. The blot holders come in one, two, and three well formats. This allows me to run up to six blots at a time using six different antibodies. Since each well is smaller in the three well blot holder then in the single or double blot holders, I can use a third less antibody when testing its quality.

The bottom line is that the Snap I.D. is a great and cost effective addition to any lab that does high throughput protein work using a diverse array of antibodies. The sensitivity, however, can stand to be a bit better.