To survive and prosper, living cells continually respond and adapt to changes in their environment. To this end, they have developed sensing systems that rival the best man-made sensing devices. Yet, how accurately these systems can measure chemical concentrations remains poorly understood. Researchers from AMOLF have now developed a theory that predicts the optimal design that maximizes the sensing precision of these systems. An analysis of experimental data revealed that the sensing system of the bacterium E. coli obeys the design principles as predicted by their theory. The AMOLF team presented their work in the journal eLife.