Research Center for Analytical Sciences, Chemistry Department, College of Sciences, Northeastern University, Shenyang, 110819, China.
Liaoning Diabetes Treatment Center, Shenyang, 110015, China.
Anal Chim Acta. 2019 Nov 8;1080:146-152. doi: 10.1016/j.aca.2019.06.051. Epub 2019 Jun 29.
Field-amplified stacking (FAS) is a commonly used method for enhancing the sensitivity of charged species from low conductive media in capillary electrophoresis. FAS also showed significant sensitivity enhancement effect on a uniform paper fluidic channel by proper design of the electrolyte. In this paper, a novel method of introducing electric field gradient is proposed by geometry design of a 2D paper fluidic channel, and field amplification effect was successfully demonstrated with reduced requirement on the sample's conductivity. Sensitive colorimetric detection of microalbuminuria (MAU) from urine samples was demonstrated by mobile phone camera. Experimental results showed that, with active electric field motivation, up to 93.5% of the loaded protein probe could be effectively transferred and stacked into a narrow band on the newly designed paper fluidic channel. A limit of detection (LOD) of 6.5 mg‧L HSA was achieved with a dynamic range of 10-300 mg‧L (linear in the range of 10-100 mg‧L, R = 0.991). Combined with selective staining of albumin with bromophenol blue (BPB), the established method was applied to the detection of MAU from clinical urine samples, and consistent results with that of the clinical method were obtained. With this paper-based analytical device (PAD), MAU from highly conductive urine samples can be directly loaded and detected without any pretreatment. This method provides a way to develop highly sensitive point-of-care test (POCT) for rapid screening of some diseases.
场放大堆积（FAS）是一种常用于增强毛细管电泳中低电导率介质中带电物质灵敏度的方法。通过适当设计电解质，FAS 还对均匀的纸流道显示出显著的灵敏度增强效果。本文通过 2D 纸流道的几何设计提出了一种引入电场梯度的新方法，并通过降低样品电导率的要求成功地证明了场放大效应。通过手机摄像头实现了对尿液样本中微量白蛋白尿（MAU）的灵敏比色检测。实验结果表明，在主动电场激励下，多达 93.5%的加载蛋白质探针可以有效地转移并堆积到新设计的纸流道上的一个窄带中。通过检测人血清白蛋白（HSA）得到了 6.5mg·L -1 的检测限（LOD），线性范围为 10-100mg·L -1 （R 2 = 0.991）。结合溴酚蓝（BPB）对白蛋白的选择性染色，该方法被应用于临床尿液样本中 MAU 的检测，与临床方法得到的结果一致。使用这种基于纸的分析器件（PAD），可以直接加载和检测高导电性尿液样本中的 MAU，而无需任何预处理。该方法为开发用于快速筛选某些疾病的高灵敏度即时检测（POCT）提供了一种途径。
