Genetically encoded biosensors measure living cells' charge in real time

Biological cells have many vital functions in the organism. For example, they produce proteins, carbohydrates and fats. But they are also responsible for detoxifying harmful molecules and transmitting signals and immune defense steps. A so-called redox potential is required to drive these processes. It depends on the ratio of NADPH (nicotinamide adenine dinucleotide phosphate in negatively charged, "reduced" form) to its oxidized form NADP⁺.