Maybe this is a silly question to ask, but I am still curious. The sandwich was made correctly but at the moment of putting it into the transfer box, the cassette was in the wrong direction (i.e. transparent side of the sandwich facing black side of the box), this way the proteins will run towards the filter and not to the membrane. Is it possible to transfer them back to the gel and then to the membrane if you just turn around the cassette or the damage is done?