Higher sample volumes and protein amounts can be applied with paper bridges that are placed between the anodic or cathodic end of the Immobiline® DryStrip gel and the electrode strip. A large sample volume requires a large paper pad applied at the opposite end to absorb excess water.
Paper bridges and electrode pads are cut from 1-mm-thick CleanGel electrode strips (see ordering information) to a size of 15 × 25 mm and with an arrowhead as shown in Figure 1. The rehydrated Immobiline® DryStrip gel is positioned directly on the glass bottom of the Immobiline® DryStrip tray. Up to four Immobiline® DryStrip gels can be run simultaneously on the Multiphor II Electrophoresis System. The arrow-headed paper, to which 375 µl sample solution has been added, is then positioned at the anodic or the cathodic end of the Immobiline® DryStrip gel.
To hold the paper bridge and Immobiline® DryStrip gel in place, press a sample cup positioned on the sample cup bar down on top of the arrowhead. A solution containing up to 10 mg protein (in 850 µL sample solution applied to a 15 × 50 paper bridge) can be loaded on an 18-cm-long, narrow-pH-range Immobiline® DryStrip gel under favorable conditions (74). The application point (anodic or cathodic) is of key importance for obtaining good results.
Figure 1.Setup for sample application via a paper bridge