Uric acid (UA) is an important biomarker for many diseases. A sensitive point-of-care (POC) testing platform is designed for the digital quantification of salivary UA based on a colorimetric reaction on an easy-to-build smartphone-assisted microfluidic paper-based analytical device (SμPAD). UA levels are quantified according to the color intensity of Prussian blue on the SμPAD with the aid of a MATLAB code or a smartphone APP. A color correction method is specifically applied to exclude the light effect. Together with the engineering design of SμPADs, the background calibration function with the APP increases the UA sensitivity by 100-fold to reach 0.1 ppm with a linear range of 0.1–200 ppm. The assay time is less than 10 min. SμPADs demonstrate a correlation of 0.97 with a commercial UA kit for the detection of salivary UA in clinical samples. SμPADs provide a sensitive, fast, affordable, and reliable tool for the noninvasive POC quantification of salivary UA for early diagnosis of abnormal UA level-associated health conditions.

中文翻译：

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使用智能手机辅助的 μPAD 对唾液尿酸进行灵敏的床旁检测的数字量化方法

尿酸（UA）是许多疾病的重要生物标志物。基于易于构建的智能手机辅助微流控纸基分析装置 (SμPAD) 上的比色反应，设计了一个灵敏的床旁 (POC) 测试平台，用于对唾液 UA 进行数字量化。借助 MATLAB 代码或智能手机 APP，根据 SμPAD 上普鲁士蓝的颜色强度对 UA 水平进行量化。专门应用了一种颜色校正方法来排除光效。结合 SμPAD 的工程设计，APP 的背景校准功能将 UA 灵敏度提高了 100 倍，达到 0.1 ppm，线性范围为 0.1-200 ppm。测定时间小于 10 分钟。SμPAD 与用于检测临床样本中唾液 UA 的商业 UA 试剂盒的相关性为 0.97。