Precision Organic Electrochemical Transistors for Single-Cell Electrophysiology

支持动态器件模型开发的有机电化学晶体管的时间分辨原位测量摘要：有机电化学晶体管(OECTS)是一类新兴的生物兼容的有机半导体器件，它工作在非常低的电压下，具有非常高的放大能力。这种特性的结合使其对外部和植入的生物电子设备具有吸引力，例如测量肌肉或神经元的电活动。然而，目前的进展受到对晶体管内部功能的不完全了解以及限制集成度和重复性的基本制造方法的限制。晶体管的内部动力学将通过一些应用于操作晶体管的显微技术来研究，以提供理论器件模型的组装信息。该模型将指导基于这些晶体管的新生物医学设备的创建，包括细胞动作电位的测量。技术：OOTS通过注入取代掺杂多离子的离子来调制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。这项研究将阐明基于导电聚合物聚(3，4-乙二氧基噻吩基)：聚苯乙烯磺酸(PEDOT：PSS)的光刻制作的OOTS的时空动力学。所建议的技术包括实时电致变色显微镜来解释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精细的尺度上的空间分布，以及原子力显微镜来揭示聚合物的形态和溶胀，这对于理解生理界面是至关重要的。这些研究将阐明离子输运和掺杂、电流流动和工作器件有源通道中的机械特性之间的相互作用，从而更好地理解结构-功能关系，并验证第一个完整的OECT功能的瞬时模型。这一认识将指导研究改进的制造方法，包括紫外线光刻和表面活性剂，这些方法已被证明可以改善其他有机电子器件的性能和重复性。可重复的光刻制造将实现设备集成和超出当前能力的精确测量。这些优化传感器的性能将通过与神经样肌细胞和骨骼肌细胞的集成来展示，这些细胞将被生物打印到OECT阵列和多电极阵列的栅极上进行比较。这项工作将在当地一家生物技术公司和两名加州大学细胞生物学合作者的协助下进行。作为本科生和外展计划的一部分，将设计和建造一个连接到OECT阵列的低噪声、多路复用的电气接口。

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.