Abstract: The present invention relates to systems, devices, kits, and methods employing liquid activated devices and systems. In certain embodiments, the liquid activated devices comprise a base substrate and a chamber sealing system (CSS) and/or a sealed reservoir system (SRS). In some embodiments, the CSS is sealed inside the reservoir of the SRS by a liquid degradable membrane. In particular embodiments, a liquid (e.g., saliva) un-seals the reservoir exposing the CSS, which seals the micro-chamber therein upon exposure to the liquid (e.g., trapping some of the liquid in the micro-chamber for analysis).