An Fe-organic framework/arginine-glycine-aspartate peptide-modified sensor for electrochemically detecting nitric oxide released from living cells.

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.

Rapid real-time monitoring of NO released from living cells using multi-walled carbon nanotube-7,7,8,8-tetracyanoquinonedimethyl-polylysine sensors.

Nitric oxide (NO) is an important but short-lived signaling molecule that is released from living cells. Real-time monitoring of NO release is useful for understanding normal cellular physiology and pathology. Herein, a convenient and efficient NO sensor was developed using multiwalled carbon nanotubes (MWCNTs)-7,7,8,8-tetracyanoquinodimethan (TCNQ)-polylysine (PLL) modified screen-printed electrode (SPE). The construction of the sensor (MWCNTs/TCNQ/PLL/SPE) was based on the synergic effect of the good conductivity of TCNQ and the high surface area of MWCNTs. The introduction of the cell-adhesive molecule PLL significantly enhanced the cytocompatibility, resulting in excellent cell attachment and growth. The resulting MWCNTs/TCNQ/PLL/SPE was successfully used for the real-time detection of NO released from living human umbilical vein endothelial cells (HUVECs) cultured on it. The MWCNTs/TCNQ/PLL/SPE was further used to detect NO release from oxidative-injured HUVECs with and without resveratrol to also preliminarily assess the effect of resveratrol against oxidative damage. The sensor developed in this study showed good performance for the real-time detection of NO released by HUVECs under different conditions and has potential applications in the diagnosis of biological processes and the screening of drug treatment effects.