Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, Anhui, 230009, China.
Anal Bioanal Chem. 2018 Apr;410(10):2647-2655. doi: 10.1007/s00216-018-0939-4. Epub 2018 Feb 17.
In this work, a multilayer-modified paper-based colorimetric sensing platform with improved color uniformity and intensity was developed for the sensitive and selective determination of uric acid and glucose with smartphone as signal readout. In detail, chitosan, different kinds of chromogenic reagents, and horseradish peroxidase (HRP) combined with a specific oxidase, e.g., uricase or glucose oxidase (GOD), were immoblized onto the paper substrate to form a multilayer-modified test paper. Hydrogen peroxide produced by the oxidases (uricase or GOD) reacts with the substrates (uric acid or glucose), and could oxidize the co-immoblized chromogenic reagents to form colored products with HRP as catalyst. A simple strategy by placing the test paper on top of a light-emitting diode lamp was adopted to efficiently prevent influence from the external light. The color images were recorded by the smartphone camera, and then the gray values of the color images were calculated for quantitative analysis. The developed method provided a wide linear response from 0.01 to 1.0 mM for uric acid detection and from 0.02 to 4.0 mM for glucose detection, with a limit of detection (LOD) as low as 0.003 and 0.014 mM, respectively, which was much lower than for previously reported paper-based colorimetric assays. The proposed assays were successfully applied to uric acid and glucose detection in real serum samples. Furthermore, the enhanced analytical performance of the proposed method allowed the non-invasive detection of glucose levels in tear samples, which holds great potential for point-of-care analysis. Graphical abstract ᅟ.
在这项工作中，开发了一种具有改进颜色均匀性和强度的多层修饰纸基比色传感平台，可用于智能手机作为信号读取的灵敏和选择性尿酸和葡萄糖的测定。具体而言，壳聚糖、各种显色试剂和辣根过氧化物酶（HRP）与特定的氧化酶（如尿酸酶或葡萄糖氧化酶（GOD）结合，固定在纸基质上形成多层修饰试纸。氧化酶（尿酸酶或 GOD）产生的过氧化氢与底物（尿酸或葡萄糖）反应，并可氧化共固定的显色试剂，在 HRP 作为催化剂的情况下形成有色产物。采用将试纸放置在发光二极管灯上方的简单策略，可有效地防止外部光的影响。通过智能手机摄像头记录颜色图像，然后计算颜色图像的灰度值进行定量分析。所开发的方法提供了尿酸检测的 0.01 至 1.0 mM 的宽线性响应范围，葡萄糖检测的 0.02 至 4.0 mM 的宽线性响应范围，检测限（LOD）分别低至 0.003 和 0.014 mM，远低于以前报道的纸基比色测定法。该方法已成功应用于实际血清样品中尿酸和葡萄糖的检测。此外，所提出的方法的增强分析性能允许在泪样中进行葡萄糖水平的非侵入性检测，这为即时检测分析提供了很大的潜力。
