University of Cincinnati - Chemistry, 312 College Dr., 404 Crosley Tower, Cincinnati, OH, 45221-0172, USA.
Anal Bioanal Chem. 2020 Sep;412(24):6287-6294. doi: 10.1007/s00216-020-02493-z. Epub 2020 Feb 17.
Here, we developed a microfluidic electrochemical flow cell for fast-scan cyclic voltammetry which is capable of rapid on-chip dilution for efficient and cost-effective electrode calibration. Fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes is a robust electroanalytical technique used to measure subsecond changes in neurotransmitter concentration over time. Traditional methods of electrode calibration for FSCV require several milliliters of a standard. Additionally, generating calibration curves can be time-consuming because separate solutions must be prepared for each concentration. Microfluidic electrochemical flow cells have been developed in the past; however, they often require incorporating the electrode in the device, making it difficult to remove for testing in biological tissues. Likewise, current microfluidic electrochemical flow cells are not capable of rapid on-chip dilution to eliminate the requirement of making multiple solutions. We designed a T-channel device, with microchannel dimensions of 100 μm × 50 μm, that delivered a standard to a 2-mm-diameter open electrode sampling well. A waste channel with the same dimensions was designed perpendicular to the well to flush and remove the standard. The dimensions of the T-microchannels and flow rates were chosen to facilitate complete mixing in the delivery channel prior to reaching the electrode. The degree of mixing was computationally modeled using COMSOL and was quantitatively assessed in the device using both colored dyes and electrochemical detection. On-chip electrode calibration for dopamine with FSCV was not significantly different than the traditional calibration method demonstrating its utility for FSCV calibration. Overall, this device improves the efficiency and ease of electrode calibration. Graphical abstract.
在这里，我们开发了一种用于快速扫描循环伏安法的微流控电化学流动池，该流动池能够快速进行芯片上稀释，从而实现高效、经济高效的电极校准。碳纤维微电极上的快速扫描循环伏安法（FSCV）是一种强大的电分析技术，用于测量随时间推移神经递质浓度的亚秒级变化。FSCV 的传统电极校准方法需要几毫升标准溶液。此外，由于必须为每个浓度制备单独的溶液，因此生成校准曲线可能很耗时。过去已经开发了微流控电化学流动池；然而，它们通常需要将电极整合到设备中，这使得在生物组织中进行测试时难以移除。同样，当前的微流控电化学流动池不能快速进行芯片上稀释以消除需要制备多个溶液的要求。我们设计了一个 T 型通道装置，微通道尺寸为 100 μm×50 μm，将标准溶液输送到 2 毫米直径的开放电极采样井中。设计了一个具有相同尺寸的废液通道，与井垂直，以冲洗和去除标准溶液。T 型微通道的尺寸和流速选择为在到达电极之前在输送通道中实现完全混合。使用 COMSOL 对混合程度进行了计算建模，并使用有色染料和电化学检测在设备中对其进行了定量评估。使用 FSCV 对多巴胺进行的芯片上电极校准与传统校准方法没有显著差异，证明了其在 FSCV 校准中的实用性。总的来说，该装置提高了电极校准的效率和易用性。
