Redox potential is of key importance in the control and regulation of cellular function and lifecycle, and previous approaches to measuring the biological redox potential noninvasively in real time are limited to areas of hypoxia or normoxia. In this paper, we extend our previous work on nanoparticle-based intracellular nanosensors to cover a much wider redox potential range of −470 to +130 mV vs NHE, which includes the redox potential range occupied by cells in a state of oxidative stress. The nanosensors are rationally designed to target different areas of this redox potential range and are monitored by surface-enhanced Raman spectroscopy, which will permit noninvasive real-time imaging of cells undergoing oxidative stress.