Nanites

Nanites (a.k.a. nanobots or nanomachines) are a form of technology available to terrans and protoss.

Overview
Medics have access to medical nanobots, which are programmed for cellular hyper-repair. Medivac dropships can likewise carry out healing functions via nanomachines.

Regenerative bio-steel is a material that uses internal nanobots to slowly repair hull damage. However, the rate of repair is much slower than that carried out by SCVs.

Simulant corruptors were equipped with self-replicating nanites that were programmed to function identically to the zerg corruptor's spores.

The protoss were able to develop anti-zerg nanites that could at least temporarily reverse the infestation process of terrans.