Precision Organic Electrochemical Transistors for Single-Cell Electrophysiology

非技术：有机电化学晶体管（OECTs）是一类新兴的生物相容性有机半导体器件，工作在极低的电压和非常高的放大。这种特性的结合使得它们对外部和植入生物电子学（如测量肌肉或神经元的电活动）具有吸引力。然而，由于对晶体管内部功能的不完全了解，以及基本的制造方法限制了集成和可重复性，目前的进展受到限制。晶体管的内部动力学将通过应用于操作晶体管的许多显微技术来研究，以告知理论器件模型的组装。该模型将指导基于这些晶体管的新型生物医学设备的创造，包括细胞动作电位的测量。技术：OECTs通过注入取代掺杂多离子的离子来调节聚合物半导体的导电性，可逆地将聚合物通道转变为绝缘体。本研究将阐明基于导电聚合物聚（3,4-乙烯二氧噻吩）：聚苯乙烯磺酸盐（PEDOT:PSS）的光刻制造oect的时空动力学。提出的技术包括实时电致变色显微镜来阐明开关过程中的原位掺杂动力学，扫描开尔文探针显微镜来测量聚合物掺杂在更细尺度上的空间分布，以及AFM来揭示聚合物的形态和膨胀，这对理解生理界面至关重要。这些研究将阐明工作器件有源通道中离子输运和掺杂、电流流动和力学性能的相互作用，从而更好地理解结构-功能关系，并验证第一个完整的OECT功能瞬态模型。这种理解将指导改进的制造方法的研究，包括UV光刻和表面活性剂，这些方法已被证明可以提高其他有机电子器件的性能和可重复性。可重复的光刻制造将使设备集成和精度测量超出当前的能力。这些优化传感器的性能将通过与神经样细胞和骨骼肌细胞的整合来证明，这些细胞将被生物打印到OECT阵列和多电极阵列的门上进行比较。这项工作将在当地一家生物技术公司和两名CU细胞生物学合作者的协助下进行。作为本科生和拓展项目的一部分，将设计和建造一个低噪声、多路复用的OECT阵列电气接口。

Time-resolved in-situ metrology of organic electrochemical transistors to support the development of a dynamic device modelAbstract Nontechnical: Organic electrochemical transistors (OECTs) are an emerging class of biocompatible organic semiconductor device that operate at very low voltages and with very high amplification. This combination of properties makes them attractive for external and implanted bioelectronics such as measuring electrical activity of muscles or neurons. However, progress is currently limited by incomplete understanding of the internal functioning of the transistors and also rudimentary fabrication methods that restrict integration and repeatability. The internal dynamics of the transistors will be studied with a number of microscopy techniques applied to operating transistors to inform the assembly of a theoretical device model. This model will guide the creation of new biomedical devices based on these transistors including the measurement of cellular action potentials.Technical: OECTs modulate the conductivity of a polymer semiconductor by injecting ions that replace dopant polyions, reversibly transforming the polymer channel into an insulator. This study will elucidate the spatio-temporal dynamics of lithographically-fabricated OECTs, based on the conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). The proposed techniques include real-time, electrochromic microscopy to elucidate the in situ doping dynamics during switching, scanning Kelvin probe microscopy to measure the spatial distribution of polymer doping on even finer scales, and AFM to reveal polymer morphology and swelling that are critical to understanding the physiological interface. These studies will elucidate the interplay of ion transport and doping, current flow, and mechanical properties in the active channel of working devices, leading to a better understanding of the structure-function relationship and validation of the first complete transient model of OECT function. This understanding will guide the study of improved fabrication methods including UV photolithography and surfactants that have been shown to improve performance and repeatability of other organic electronic devices. Repeatable photolithographic fabrication will enable device integration and precision measurements beyond current capability. Performance of these optimized sensors will be demonstrated by integration with nerve-like and skeletal myocyte cells, which will be bio-printed onto the gates of OECT arrays and a multi-electrode array for comparison. This will be performed with the assistance of a local bio-tech firm and two CU cell biology collaborators. A low-noise, multiplexed electrical interface to the OECT array will be designed and built as part of the undergraduate and outreach program.