Babyproofing challenge - spiral floating staircase

The title describe the challenge I have. I need to make our spiral floating staircase safe. I do plan on installing the gate on top and bottom, but I was curious if I can put something underneath the stair to make sure that baby is not falling throught spaces between steps. Does something like this exist? Any ideas? This is our main staircase to the second floor and I am using it a lot. Gates are fine for the beginning but baby needs to learn to use it at some point and I am really nervious about safety.