Tufts University, Medford, MA, USA.
Analyst. 2018 Feb 26;143(5):1059-1064. doi: 10.1039/c7an01837a.
Paper-based microfluidic devices with screen-printed electrodes (SPEs) for electrochemical sensing are popular for low-cost point-of-care diagnostics. The electroactive sensing area in these devices is always the irregular, bottom-SPE surface which is in contact with the analyte flowing within the paper substrate. Unfortunately, this results in an electroactive area which varies widely from sensor to sensor. In this paper, we present a three-dimensional paper-based analytical device with a hollow 3D fluid reservoir which allows for use of a more uniform top-SPE surface as the electroactive sensing area. The use of this isolated reservoir eliminates the need for dielectric inks used in conventional SPEs on paper. Our sensors are fabricated using a combination of wax-printing, screen-printing and simple folding via a cleanroom free process without the need for expensive equipment. Additionally, for the first time, we demonstrate an electrochemical paper-based analytical device with a custom designed potentiostat integrated circuit (IC) as a miniaturized reader. The versatility of the sensor is demonstrated through voltammetric, amperometric and potentiometric measurements of important biochemical analytes such as dopamine, glucose and pH. The 3D ePAD together with a custom CMOS potentiostat demonstrates a low-cost, versatile, self-contained system suitable for point-of-care diagnostic devices.
基于纸张的微流控器件具有丝网印刷电极（SPE），可用于电化学传感，因其低成本、即时诊断而广受欢迎。这些器件中的电活性传感区域始终是不规则的、与纸基体内流动的分析物接触的底部 SPE 表面。不幸的是，这导致电活性区域在传感器之间差异很大。在本文中，我们提出了一种具有中空 3D 储液池的三维纸张分析器件，该储液池可用于更均匀的顶部 SPE 表面作为电活性传感区域。使用这种隔离储液器消除了在纸张上使用传统 SPE 所需的介电油墨。我们的传感器是使用蜡印、丝网印刷和通过无尘室免费工艺简单折叠制造的，无需昂贵的设备。此外，我们首次展示了一种具有定制设计的电化学纸张分析器件的集成运算放大器集成电路（IC）作为微型读取器。该传感器的多功能性通过伏安法、安培法和电位法对重要的生化分析物（如多巴胺、葡萄糖和 pH 值）进行了测量。3D ePAD 与定制的 CMOS 集成运算放大器一起展示了一种低成本、多功能、自给自足的系统，适用于即时诊断设备。
