Real-time and in-situ monitoring of H₂O₂ release from living cells by a stretchable electrochemical biosensor based on vertically aligned gold nanowires

Traditional electrochemical biosensing electrodes (e.g., gold disk, glassy carbon electrode, etc.) can undergo sophisticated design to detect chemicals/biologicals from cells. However, such electrodes are typically rigid and nonstretchable, rendering it challenging to detect cellular activities in real-time and in situ when cells are in mechanically deformed states. Here, we report a new stretchable electrochemical cell-sensing platform based on vertically aligned gold nanowires embedded in PDMS (v-AuNWs/PDMS). Using H₂O₂ as a model analyte, we show that the v-AuNWs/PDMS electrode can display an excellent sensing performance with a wide linear range, from 40 μM to 15 mM, and a high sensitivity of 250 mA/cm²/M at a potential of -0.3 V. Moreover, living cells can grow directly on our stretchable high-surface area electrodes with strong adhesion, demonstrating their excellent biocompatibility. Further cell stimulation by adding chemicals induced H₂O₂ generation, which can be detected in real-time and in situ using our v-AuNWs/PDMS platform for both natural and stretched states of cells. Our results indicate the v-AuNWs/PDMS electrochemical biosensor may serve as a general cell-sensing platform for living organisms under deformed states.