An Fe-organic framework/arginine–glycine–aspartate peptide-modified sensor for electrochemically detecting nitric oxide released from living cellsElectronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3bm00923h

Nitric oxide (NO) is a crucial cell-signaling molecule utilized in numerous physiological and pathological processes. Monitoring cellular levels of NO requires a sensor with sufficient sensitivity, transient recording capability, and biocompatibility. Owing to the large surface area and high catalytic activity of the metal–organic framework, Fe–BTC was used for the modification of screen-printed electrodes (SPEs). This study investigates the electrochemical sensing of NO on modified SPEs. Additionally, the introduction of a cell-adhesive molecule, arginine–glycine–aspartate peptide (RGD), considerably improved the cytocompatibility, resulting in superior cell attachment and growth on the SPE. The Fe–BTC/RGD-modified SPE (Fe–BTC/RGD/SPE) exhibited electrocatalytic NO oxidation at 0.8 V, demonstrating a linear response with a detection limit of 11.88 nM over a wide concentration range (0.17–47.37 μM) and a response time of approximately 0.9 s. Subsequently, the as-obtained Fe–BTC/RGD/SPE was successfully utilized for the real-time detection of NO released from human endothelial cells cultured on the electrode. Therefore, the study undertaken shows remarkable potential of Fe–BTC/RGD/SPE for practical applications in biological processes and clinical diagnostics.