Precise and continuous monitoring of biochemicals by biosensors assists to understand physiological functions for various diagnostics and therapeutic applications. For implanted biosensors, small size and flexibility are essential for minimizing tissue damage and achieving accurate detection. However, the active surface area of sensor decreases as the sensor becomes smaller, which will increase the impedance and decrease the signal to noise ratio, resulting in a poor detection limit. Taking advantages of local amplification effect, organic electrochemical transistors (OECTs) constitute promising candidates for high-sensitive monitoring. However, their detections in deep tissues are rarely reported. Herein, we report a family of implantable, fiber-shaped all-in-one OECTs based on carbon nanotube fibers for versatile biochemical detection including H₂O₂, glucose, dopamine and glutamate. These fiber-shaped OECTs demonstrated high sensitivity, dynamical stability in physiological environment and anti-interference capability. After implantation in mouse brain, 7-day dopamine monitoring in vivo was realized for the first time. These fiber-shaped OECTs could be great additions to the “life science” tool box and represent promising avenue for biomedical monitoring.

生物传感器对生物化学物质的精确和连续监控有助于了解各种诊断和治疗应用的生理功能。对于植入的生物传感器，小尺寸和柔性对于最小化组织损伤和实现精确检测至关重要。但是，传感器的有效表面积会随着传感器的变小而减小，这将增加阻抗并降低信噪比，从而导致检测限变差。利用局部放大效应，有机电化学晶体管（OECT）构成了高灵敏度监测的有希望的候选者。但是，很少报道其在深层组织中的检测。本文中，我们报告了一系列基于碳纳米管纤维的可植入纤维状多合一OECT，可用于多种生化检测，包括H₂ O ₂，葡萄糖，多巴胺和谷氨酸。这些纤维状的OECTs具有很高的灵敏度，在生理环境中的动态稳定性和抗干扰能力。植入小鼠脑后，首次实现了7天的体内多巴胺监测。这些纤维状的OECTs可能是“生命科学”工具箱的重要补充，代表了生物医学监测的有希望的途径。