Since very weak interactions are sufficient to significantly decohere a quantum system, quantum systems can potentially be used as very sensitive force sensors if their decoherence is monitored. This monitoring can take the form of interferometric measurements in which the fringe visibility is measured as a function of time or some experimental parameter. The main challenge would presumably be to isolate the system well enough from all the other interactions which also cause decoherence but which you don't want to measure.
A google search for "decoherence microscopy" will bring up some proposals. Another good starting point are the papers of the group of Markus Arndt, e.g. "Quantum interference of clusters and molecules" in Rev.Mod.Phys., in particular the section on "interference-assisted measurements".