Wei Xiaofeng, Tian Tian, Jia Shasha, Zhu Zhi, Ma Yanli, Sun Jianjun, Lin Zhenyu, Yang Chaoyong James
MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, Key Laboratory for Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
MOE Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University , Fuzhou, Fujian 350116, China.
Anal Chem. 2016 Feb 16;88(4):2345-52. doi: 10.1021/acs.analchem.5b04294. Epub 2016 Jan 27.
A disposable, equipment-free, versatile point-of-care testing platform, microfluidic distance readout sweet hydrogel integrated paper-based analytical device (μDiSH-PAD), was developed for portable quantitative detection of different types of targets. The platform relies on a target-responsive aptamer cross-linked hydrogel for target recognition, cascade enzymatic reactions for signal amplification, and microfluidic paper-based analytic devices (μPADs) for visual distance-based quantitative readout. A "sweet" hydrogel with trapped glucoamylase (GA) was synthesized using an aptamer as a cross-linker. When target is present in the sample, the "sweet" hydrogel collapses and releases enzyme GA into the sample, generating glucose by amylolysis. A hydrophilic channel on the μPADs is modified with glucose oxidase (GOx) and colorless 3,3'-diaminobenzidine (DAB) as the substrate. When glucose travels along the channel by capillary action, it is converted to H2O2 by GOx. In addition, DAB is converted into brown insoluble poly-3,3'-diaminobenzidine [poly(DAB)] by horseradish peroxidase, producing a visible brown bar, whose length is positively correlated to the concentration of targets. The distance-based visual quantitative platform can detect cocaine in urine with high selectivity, sensitivity, and accuracy. Because the target-induced cascade reaction is triggered by aptamer/target recognition, this method is widely suitable for different kinds of targets. With the advantages of low cost, ease of operation, general applicability, and disposability with quantitative readout, the μDiSH-PAD holds great potential for portable detection of trace targets in environmental monitoring, security inspection, personalized healthcare, and clinical diagnostics.
一种一次性、无需设备的多功能即时检测平台——微流控距离读数甜味水凝胶集成纸基分析装置（μDiSH-PAD）被开发用于便携式定量检测不同类型的目标物。该平台依靠目标响应适体交联水凝胶进行目标识别，依靠级联酶促反应进行信号放大，依靠微流控纸基分析装置（μPAD）进行基于视觉距离的定量读数。使用适体作为交联剂合成了一种包埋有葡萄糖淀粉酶（GA）的“甜味”水凝胶。当样品中存在目标物时，“甜味”水凝胶会塌陷并将酶GA释放到样品中，通过淀粉分解产生葡萄糖。μPAD上的亲水通道用葡萄糖氧化酶（GOx）和无色的3,3'-二氨基联苯胺（DAB）作为底物进行修饰。当葡萄糖通过毛细作用沿通道移动时，它会被GOx转化为H2O2。此外，DAB会被辣根过氧化物酶转化为棕色不溶性聚3,3'-二氨基联苯胺[聚（DAB）]，产生可见的棕色条带，其长度与目标物浓度呈正相关。基于距离的视觉定量平台能够以高选择性、高灵敏度和高准确性检测尿液中的可卡因。由于目标诱导的级联反应是由适体/目标识别触发的，该方法广泛适用于不同种类的目标物。μDiSH-PAD具有低成本、操作简便、普遍适用性强以及可定量读数且一次性使用的优点，在环境监测、安全检查、个性化医疗保健和临床诊断中对痕量目标物进行便携式检测方面具有巨大潜力。
