Fig. 2. Nanomotors as active self-powered sensors. (A) Changes in the swimming behavior of the artificial micromotor (microfish) as a function of concentration upon 2 min exposure to Hg, Cu, sodium azide and aminotriazole. The solution contains 5% sodium cholate (NaCh), and 2% hydrogen peroxide (H₂O₂). Reprinted with permission from ref. 41. Copyright 2013, American Chemical Society. (B) Influence of the concentration of DMSO, cysteine and serine on the velocities of the microjets. Tracking data were obtained for a timescale of 10 seconds from 5 independently running experiments in order to get the average speed. The solution contains 1% sodium dodecyl sulfate (SDS) and 9% hydrogen peroxide (H₂O₂). Both schematics on the right panels illustrate the poisoning of micromotors – either enzymatic or Pt-based – upon presence of particular analytes. Reprinted with permission from ref. 44. Copyright 2013, Royal Society of Chemistry.