One of the most asked and experimented with in the alcohol ink communities is all about sealing tiles and YUPO paper.
From my personal experience the sealant I have found to be working well for tiles is Krylon Triple Thick Crystal Glaze. I may use several coats. Spray lightly from about 12 inches away. Let each coat dry thoroughly before adding another coat. Once I have put on 3 coats I let the art cure for about a week before letting anything touch it.
Many artist swear by Krylon Kamar for at least a first coat. I personally have not tried this YET but a lot of artists seem to love it.