In this article, we present the first demonstration of a distance-based paper analytical device (dPAD) for uric acid quantification in human urine samples with instrument-free readout and user-friendliness for the rapid diagnosis and prognosis of various related diseases. By employing gold nanoparticles (AuNPs) as a peroxidase-like nanozyme, our proposed technique eliminates the utilization of horseradish peroxidase (HRP), making the device cost-effective and stable. In our dPAD, uric acid in the sample is oxidized by the uricase enzyme and subsequently catalysed with AuNPs in the sample zone, generating hydroxyl radicals (˙OH). Then, the produced ˙OH reacts with 3,3′-diaminobenzidine (DAB) to form poly DAB (oxDAB), resulting in a coloured distance signal in the detection zone of the dPAD. The variation of the distance of the observed red-brown colour is directly proportional to the uric acid concentration. Our sensor exhibited a linear range from 0.50 to 6.0 mmol L⁻¹ (R² = 0.9922) with a detection limit (LOD) of 0.25 mmol L⁻¹, covering the clinical range of uric acid in urine. Hence, there is no need for additional sample preparation or dilution. Additionally, this assay is highly selective, with no interferences. We also found that this approach could accurately and precisely determine uric acid in human control samples with the recovery ranging from 99.37 to 100.35 with the highest RSD of 4.05%. Our method is comparable with the use of a commercially available uric acid sensor at a 95% confidence interval. Consequently, the developed dPAD offers numerous advantages such as cost-effectiveness, simplicity, and ease of operation with unskilled individuals. Furthermore, this concept can be applied for extensive biosensing applications in monitoring other biomarkers as an alternative analytical point-of-care (POC) device.

中文翻译：

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一种用于人尿液样品中尿酸定量的金纳米材料集成距离分析装置


在本文中，我们首次演示了用于定量人尿液样本中尿酸的基于距离的纸张分析设备 （dPAD），该设备具有无需仪器的读数和用户友好的功能，可用于各种相关疾病的快速诊断和预后。通过使用金纳米颗粒 （AuNPs） 作为类似过氧化物酶的纳米酶，我们提出的技术消除了辣根过氧化物酶 （HRP） 的使用，使该设备具有成本效益和稳定性。在我们的 dPAD 中，样品中的尿酸被尿酸酶氧化，随后在样品区被 AuNP 催化，产生羟基自由基 （ ̇OH）。然后，产生的 ̇OH 与 3,3′-二氨基联苯胺 （DAB） 反应形成聚 DAB （oxDAB），在 dPAD 的检测区产生彩色距离信号。观察到的红棕色距离的变化与尿酸浓度成正比。我们的传感器表现出 0.50 至 6.0 mmol ^L-1 （R² = 0.9922） 的线性范围，检测限 （LOD） 为 0.25 mmol ^L-1，涵盖了尿液中尿酸的临床范围。因此，无需额外的样品制备或稀释。此外，该检测具有高度选择性，无干扰。我们还发现，这种方法可以准确、精密地测定人对照样品中的尿酸，回收率范围为 99.37 至 100.35，最高 RSD 为 4.05%。我们的方法与使用 95% 置信区间的市售尿酸传感器相当。因此，开发的 dPAD 具有许多优势，例如成本效益、简单性和易于操作，即使不熟练的人也能操作。 此外，这一概念可应用于广泛的生物传感应用，作为替代的分析即时检测 （POC） 设备，监测其他生物标志物。