Structure gel is a black, liquid substance possibly originally manufactured by Carthage Industries, with the WAU administering the substance all over PATHOS-II in order to perform maintenance and construction work, seemingly being the only other producer of the substance other than Carthage Industries.
In SOMA, structure gel is seen in various roles throughout the game, most notably being encountered around structural damage where excessive leakage can start forming large amounts of debris in the affected area.
Structure gel is a highly proteinated, cross-linked lubricant, and a conductor, and a signal medium, with aligned graphene in a petroleum monosubstrate, polysaturated matrix, containing fuel oils. The gel is encodable and can be calibrated with instructions to accomplish a specific function. The gel can only function for a limited duration if no external sources of electricity provides power.
The substance is very useful in technology, able to connect different forms of machinery and even increase the functionality of basic machines immensely. The gel can reboot any offline machine and repair any structural or electrical damage. It can even bring biological life back to a "sleepwalking" reanimated state, using electrical impulses both to guide the pseudo-organism and to prevent the gel from hardening. Even human bodies can be "revived" this way. Personnel often treated the pre-WAU robots with the gel to maintain them.
Structure gel is harmless to humans in small doses but large doses cause nausea and possibly a state of coma, there is no treatment for over-exposure.
All of the structure gel in PATHOS-II was linked to the WAU, which gave the A.I. complete control of any machine or structure infused with the gel.
In 2103, the WAU calibrated the structure gel in such a manner that doesn't necessarily make sense, it acted as a cancerous growth when used. The WAU then caused the gel to overflow Pathos-II; bursting through pipes in walls or floors or ceilings and covering machinery.
- On the bottle of structure gel is a label denoting hazards, production number, and a QR code. If scanned, the QR code says "structure gel 023343".
- Although structure gel is black in color, it often has blue-tinted lights coming from small nodes in it. This is similar to how certain aquatic organisms can exhibit bio-luminescence.
- At one point, Simon comes across a deceased rat inside a specimen chamber with a structure gel dispenser. Infusing the rat corpse with gel causes it to reanimate, squirming and squeaking unnaturally. Simon remarks: "It came back to life... or at least something like it."