Electrochemical Sensing of Nitric Oxide in Biological Systems

Nitric oxide (NO) is a ubiquitous signalling molecule that regulates cardiovascular function, immune responses and neurotransmission. Electrochemical sensors afford direct, real-time detection of NO by oxidising or reducing the molecule at a suitable electrode surface, converting chemical activity into measurable current. Key considerations include sensitivity to sub-nanomolar concentrations, selectivity against interferents such as nitrite or ascorbate, rapid response times and biocompatibility for in vitro or in vivo deployment. Advances in electrode materials—ranging from carbon-based substrates and noble-metal nanoparticles to two-dimensional nanomaterials—have driven improvements in electrocatalytic efficiency and surface stability. Surface modification strategies, including covalent or non-covalent functionalisation with catalytic moieties (for example metalloporphyrins) or conductive polymers, enhance electron transfer kinetics and suppress fouling. Miniaturised designs, such as microelectrode arrays and fibre-based probes, enable spatially resolved measurements in tissues and single cells. Ongoing efforts focus on integrating point-of-care platforms, wireless telemetry and multiplexed detection of NO alongside other redox mediators to elucidate dynamic signalling networks in health and disease.

Research from Nature Portfolio

A novel approach utilises a standard acupuncture needle modified with a graphene–iron-porphyrin composite to monitor NO release in living rats. A thin gold film on the needle enhances conductivity, while electrochemical deposition of the functionalised graphene composite confers high electrocatalytic activity toward NO oxidation. Amperometric measurements reveal a detection limit below 5 nM and swift response times, with excellent selectivity in physiological buffer. In vivo insertion into specific acupoints permits direct observation of NO transients elicited by pharmacological stimulation, demonstrating the potential for repurposing traditional medical tools as minimally invasive electrochemical probes.

Electrochemical Sensing of Nitric Oxide in Biological Systems publication trend

The graph below shows the total number of articles in electrochemical sensing of nitric oxide in biological systems across all publications each year (not limited to Nature Index journals).

Technical terms

Amperometry: Measurement of current at a fixed potential to quantify analyte oxidation or reduction in real time.

Differential pulse voltammetry: A pulsed potential technique that enhances sensitivity by measuring current differences before and after each pulse.

Electrocatalysis: Acceleration of electrode reactions by catalytic surface species that lower activation energy and improve selectivity.

Limit of detection (LOD): Lowest concentration of analyte that produces a signal distinguishable from background noise.

Graphene nanocomposite: A hybrid material combining graphene with other elements (e.g. nanoparticles, polymers or biomolecules) to enhance functionality.

Porphyrin: A cyclic organic molecule often complexed with metal ions, used as biomimetic electrocatalysts for gasotransmitters like NO.

References

1. Graphene nanocomposites for real-time electrochemical sensing of nitric oxide in biological systems. Applied Physics Reviews (2023).
2. Functionalized graphene-based biomimetic microsensor interfacing with living cells to sensitively monitor nitric oxide release. Chemical Science (2015).
3. A sensitive acupuncture needle microsensor for real-time monitoring of nitric oxide in acupoints of rats. Scientific Reports (2017).
4. Gold Nanoclusters Dispersed on Gold Dendrite-Based Carbon Fibre Microelectrodes for the Sensitive Detection of Nitric Oxide in Human Serum. Biosensors (2022).
5. Development of an electrochemical sensor for nitric oxide based on carbon paste electrode modified with Nafion, gold nanoparticles and graphene nanoribbons. Sensors and Actuators B Chemical (2021).