How to make a very sticky glass printing bed without any additive

The problem I tried to solve was that my new perfectly flat printing bed in borosilicate glass was not sticky at all for PLA.

I didn't want to use the sticker papers anymore because the rendering of the surface of the objects in direct contact with the glass is so perfect !!!

I then had the idea to cross sand one of the faces of this glass sheet with 600 sand paper. If the thin scratches are almost invisible (and not visible at all on printed objects), it immediately appeared that the