Photoelectrochemical (PEC) sensing has been developing quickly in recent years, while its in vivo application is still in the infancy. The complexity of biological environments poses a high challenge to the specificity and reliability of PEC sensing. We herein proposed the concept of small-molecule organic semiconductor (SMOS)-based ratiometric PEC sensing making use of the structural flexibility as well as readily tunable energy band of SMOS. Xanthene skeleton-based CyOH was prepared as a photoactive molecule, and its absorption band and corresponding PEC output can be modulated by an intramolecular charge transfer process. As such, the target mediated shift of absorption offered the opportunity to construct a ratiometric PEC sensor. A proof-of-concept probe CyOThiols was synthesized and assembled on a Ti wire electrode (TiWE) to prepare a highly selective microsensor for thiols. Under two monochromatic laser excitation (808 nm and 750 nm), CyOThiols/TiWE offered a ratiometric signal (j₈₀₈/j₇₅₀), which exhibited pronounced capacity to offset the disturbance of environmental factors, guaranteeing its reliability for application in vivo. The ratiometric PEC sensor achieved the observation of bio-thiol release induced by cytotoxic edema and fluctuations of thiols in drug-induced epilepsy in living rat brains.

中文翻译：

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基于小分子有机半导体的比例光电化学微传感器，用于可靠的体内分析

光电化学（PEC）传感近年来发展迅速，但其在体内的应用仍处于起步阶段。生物环境的复杂性对 PEC 传感的特异性和可靠性提出了很高的挑战。我们在此提出了基于小分子有机半导体 (SMOS) 的比例 PEC 传感的概念，利用 SMOS 的结构灵活性以及易于调节的能带。制备了基于呫吨骨架的CyOH作为光活性分子，其吸收带和相应的 PEC 输出可以通过分子内电荷转移过程进行调节。因此，目标介导的吸收转移提供了构建比例 PEC 传感器的机会。概念验证探针CyOThiols合成并组装在钛线电极（TiWE）上以制备硫醇的高选择性微传感器。在两种单色激光激发（808 nm和750 nm）下，CyOThiols /TiWE提供了比例信号（j ₈₀₈ / j ₇₅₀），表现出明显的抵消环境因素干扰的能力，保证了其在体内应用的可靠性。比率 PEC 传感器实现了对活体大鼠脑中药物性癫痫中细胞毒性水肿和硫醇波动引起的生物硫醇释放的观察。