This paper describes a paper-based analytical device allowing the direct semiquantitative interpretation of the result of a chemical assay in the form of “text”. The combined use of a classical colorimetric indicator system and an additional inert colorant enables a versatile text-displaying detection mechanism on a paper device. For proof-of-concept, urinary protein has been selected as a model analytical target. The whole text-displaying paper device has been developed based on printing techniques including wax printing, inkjet printing, and 3D printing. The results of user tests performed with protein (human serum albumin) samples in aqueous standard solutions and human urine demonstrated that the accuracy was comparable for the elaborated paper device (74.7% for standard samples and 66.7% for urine) and a conventional colorimetric urine dipstick (67.2% for standard samples and 65.3% for urine). Storage stability as long as at least 117 days has been confirmed based on software-assisted quantitative color analysis. The developed text-displaying approach is proposed as an alternative simple detection motif for paper-based analytical devices.

中文翻译：

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文本显示比色纸质分析仪

本文介绍了一种基于纸张的分析设备，该设备可以以“文本”形式直接半定量解释化学分析的结果。经典比色指示系统与其他惰性着色剂的组合使用，可以在纸质设备上实现多功能的文本显示检测机制。为了进行概念验证，已选择尿蛋白作为模型分析目标。整个文本显示纸装置是基于包括蜡印刷，喷墨印刷和3D印刷的印刷技术而开发的。在水性标准溶液和人尿液中对蛋白质（人血清白蛋白）样品进行的用户测试结果表明，精密度与精制纸设备相当（标准样品为74.7％，66为准确度）。尿液为7％）和常规比色尿液试纸（标准样品为67.2％，尿液为65.3％）。根据软件辅助的定量颜色分析，可以确认至少117天的储存稳定性。提出了已开发的文本显示方法，作为基于纸张的分析设备的另一种简单检测主题。