A reversible photoelectrochemical microsensor for dynamically monitoring sulfur dioxide in the epileptic brain

Epilepsy is considered one of the most prevalent neurological disorders, yet the precise mechanisms underlying its pathogenesis remain inadequately elucidated. Emerging evidence implicates endogenous sulfur dioxide (SO2) in the brain as playing a significant role in epilepsy and associated neuronal apoptosis. Consequently, tracking the dynamic fluctuations in the levels of SO2 and its derivatives (SO32-/HSO3-) provides valuable insights into the molecular mechanisms underlying epilepsy, with potential implications for its diagnosis and therapeutic intervention. Nonetheless, the absence of reversible in vivo detection tools constitutes a formidable obstacle in the real-time monitoring of SO2 dynamics in the brain. In response to this challenge, we propose a novel approach involving a photoelectrochemical (PEC) microsensor capable of reversibly detecting SO2. This microsensor leverages a reversibly recognizing dye for SO2 and upconversion nanoparticles as the modulator of the excitation source for the photoactive material, enabling modulation of the photocurrent by the target. The reversible output of PEC signals allows for the monitoring of SO2 levels in real time in the brains of epileptic mice. This study reveals the patterns of SO2 level changes during epilepsy and provides insights into the neuroprotective mechanism of exogenous SO2. A reversible PEC microsensor (RPMS) based on FRET-modulated signal has been developed, demonstrating its effectiveness for dynamic monitoring of SO2 levels in the living brains of epileptic mice.