Real-Time and In-Situ Monitoring of H 2 O 2 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 H 2 O 2 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/cm 2 /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 H 2 O 2 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.