Ramiah Rajasekaran Pradeep, Chapin Ashley Augustiny, Quan David N, Herberholz Jens, Bentley William E, Ghodssi Reza
Institute for Systems Research, University of Maryland, College Park, MD USA.
Fischell Department of Bioengineering, University of Maryland, College Park, MD USA.
Microsyst Nanoeng. 2020 Oct 5;6:100. doi: 10.1038/s41378-020-00208-z. eCollection 2020.
This work presents a 3D-printed, modular, electrochemical sensor-integrated transwell system for monitoring cellular and molecular events in situ without sample extraction or microfluidics-assisted downstream omics. Simple additive manufacturing techniques such as 3D printing, shadow masking, and molding are used to fabricate this modular system, which is autoclavable, biocompatible, and designed to operate following standard operating protocols (SOPs) of cellular biology. Integral to the platform is a flexible porous membrane, which is used as a cell culture substrate similarly to a commercial transwell insert. Multimodal electrochemical sensors fabricated on the membrane allow direct access to cells and their products. A pair of gold electrodes on the top side of the membrane measures impedance over the course of cell attachment and growth, characterized by an exponential decrease (~160% at 10 Hz) due to an increase in the double layer capacitance from secreted extracellular matrix (ECM) proteins. Cyclic voltammetry (CV) sensor electrodes, fabricated on the bottom side of the membrane, enable sensing of molecular release at the site of cell culture without the need for downstream fluidics. Real-time detection of ferrocene dimethanol injection across the membrane showed a three order-of-magnitude higher signal at the membrane than in the bulk media after reaching equilibrium. This modular sensor-integrated transwell system allows unprecedented direct, real-time, and noninvasive access to physical and biochemical information, which cannot be obtained in a conventional transwell system.
这项工作展示了一种3D打印的模块化电化学传感器集成转孔系统，用于在无需样品提取或微流控辅助下游组学的情况下原位监测细胞和分子事件。采用3D打印、荫罩和模塑等简单的增材制造技术来制造这个模块化系统，该系统可高压灭菌、具有生物相容性，并设计为按照细胞生物学的标准操作流程（SOP）运行。该平台的核心是一个柔性多孔膜，它与商业转孔插入物类似，用作细胞培养底物。在膜上制造的多模态电化学传感器允许直接接触细胞及其产物。膜顶侧的一对金电极在细胞附着和生长过程中测量阻抗，其特征是由于分泌的细胞外基质（ECM）蛋白使双层电容增加，阻抗呈指数下降（在10 Hz时约为160%）。在膜底侧制造的循环伏安法（CV）传感器电极能够在细胞培养位点检测分子释放，而无需下游流体装置。对膜两侧注射二茂铁二甲醇的实时检测显示，达到平衡后，膜处的信号比本体介质中的信号高三个数量级。这种模块化传感器集成转孔系统允许以前所未有的方式直接、实时和非侵入性地获取物理和生化信息，而这些信息在传统转孔系统中是无法获得的。
