The trick I recently heard from some players when they bend, they use the index finger from the fretting hand (most like to be Left) to mute the string above the actual string you are bending. You do this by bending the string with your middle and ring finger and have your index finger sticking out touching slightly to "deaden" the string above, hence no open string sound. But too late for me I've already grown accustomed to bending strings the traditional way so I stick with it.