Monitoring Nitric Oxide in Trigeminal Neuralgia Rats with a Cerium Single-Atom Nanozyme Electrochemical Biosensor.

Trigeminal neuralgia (TN) is the most common neuropathic disorder; however, its pathogenesis remains unclear. A prevailing theory suggests that nitric oxide (NO) may induce nerve compression and irritation via vascular dilation, thereby being responsible for the condition, making real-time detection of generated NO critical. However, traditional evaluations of NO rely on indirect colorimetric or chemiluminescence techniques, which offer limited sensitivity and spatial resolution for its real-time assessment in biological environments. Herein, we reported the development of a highly sensitive NO electrochemical biosensor based on a cerium single-atom nanozyme (Ce1-CN) with an ultrawide linear range from 1.08 nM to 143.9 μM and an ultralow detection limit of 0.36 nM, which enables efficient and real-time evaluation of NO in TN rats. In situ attenuated total reflection surface-enhanced infrared spectroscopy combined with density functional theory calculations revealed the high-performance biosensing mechanism, whereby the Ce centers in Ce1-CN nanoenzymes adsorb NO and subsequently react with OH- to form *HNO2. Results demonstrated that NO concentration was associated with the TN onset. Following carbamazepine treatment, NO production from nerves decreased, accompanied by an alleviation of pain. These findings indicate that the biosensor serves as a valuable tool for investigating the pathogenesis of TN and guiding subsequent therapeutic strategies.