A highly adsorptive electrochemical fiber sensor for real-time and accurate detection of intracranial nitric oxide

Electrochemical nitric oxide (NO) sensors are capable of real-time monitoring of intracranial NO concentration, which is crucial for understanding the functions of NO in the brain. However, traditional rigid electrochemical sensors used in the brain face the dilemma of low sensitivity and abnormal NO concentrations caused by neuroin-flammatory responses. Here, we report a highly sensitive and accurate electrochemical NO sensor that combines both physical and chemical adsorption capabilities for NO. The physical and chemical adsorption capabilities can be attributed to the high specific surface area and abundant carboxyl functional groups of the electrode, respectively. Besides, it is soft and matches the mechanical property of brain tissue, enabling an adaptable interface. The resulting NO sensor exhibits the highest reported sensitivity of 3245 pA nmol−1 L, with a low detection limit of 0.1 nmol L−1. No significant inflammatory response or excess NO expression is observed after implantation, improving the detection accuracy. The sensor successfully captures NO fluctuations in the brain and enables simultaneous NO detection in multiple brain regions, facilitating research on NO physio-pathological actions in the brain.