开发了一种简单的基于距离的纸质分析装置 (dPAD)，用于监测人体样本中的肌氨酸水平，以快速诊断和预后前列腺癌及相关症状。该测定通过利用碳纳米点（CD）作为类过氧化物酶纳米酶，消除了对昂贵的辣根过氧化物酶（HRP）的需求。所提出的 dPAD 传感器由预先沉积有肌氨酸氧化酶 (SOx) 和 CD 的样品区以及包含 3,3',5,5'-四甲基联苯胺 (TMB) 的检测区组成。当将含有肌氨酸的溶液添加到样品区时，通过SOx氧化和随后的CD的过氧化物酶催化产生羟基自由基(·OH)。形成的•OH自由基通过毛细管力立即流向检测区，氧化TMB，导致可见的颜色从无色变为蓝色。通过测量检测区域中蓝色的距离可以轻松完成肌氨酸定量。开发的 dPAD 提供 12.5 至 35.0 nmol L-1 (R2= 0.9959) 之间的线性工作范围和 10.0 nmol L-1 的检测限 (LOD)。这涵盖了尿肌氨酸测定的临床范围，因此表明不需要额外的样品制备或稀释。该传感器具有高精度，最高相对标准偏差 (RSD) 为 4.58%，并且具有出色的选择性，没有观察到干扰。此外，人体对照尿液样本的回收率研究范围为 98.67% 至 101.50%，最高 RSD 为 2.03%。相应地，我们的 dPAD 方法与用于检测人对照血清中肌氨酸的商业 ELISA 方法的性能非常匹配。该传感器比以前的方法更具成本效益、用户友好且易于使用。总体而言，所提出的方法代表了一种有前途的肌氨酸定量分析工具。该概念还适用于检测其他生物分子的更广泛的分析应用。© 2024。作者获得 Springer-Verlag GmbH Austria（Springer Nature 旗下公司）的独家许可。

A straightforward distance-based paper analytical device (dPAD) was developed for monitoring sarcosine levels in human samples for the rapid diagnosis and prognosis of prostate cancer and related symptoms. This assay eliminates the need for the expensive horseradish peroxidase (HRP) enzyme by utilizing carbon nanodots (CDs) as a peroxidase-like nanozyme. The proposed dPAD sensor consists of a sample zone pre-deposited with sarcosine oxidase (SOx) and CDs, and a detection zone containing 3,3',5,5'-tetramethylbenzidine (TMB). When a solution containing sarcosine is added to the sample zone, hydroxyl radicals (•OH) are produced through SOx oxidation and subsequent peroxidase catalysis by the CDs. The formed •OH radicals immediately flow to the detection zone via capillary force, where they oxidize TMB, resulting in a visible colour change from colourless to blue. Sarcosine quantification is effortlessly accomplished by measuring the distance of the blue colour in the detection zone. The developed dPAD offers a linear working range between 12.5 and 35.0 nmol L-1 (R2 = 0.9959) and a detection limit (LOD) of 10.0 nmol L-1. This covers the clinical range for urinary sarcosine determination, thereby suggesting no additional sample preparation or dilution is needed. The sensor shows high precision with the highest relative standard deviation (RSD) of 4.58% and demonstrates excellent selectivity with no observed interferences. Furthermore, recovery studies in human control urine samples ranged from 98.67 to 101.50%, with the highest RSD of 2.03%. Correspondingly, our dPAD method showed a great match with the performance of a commercial ELISA method for detecting sarcosine in human control serum. The sensor is more cost-effective, user-friendly, and accessible than previous methods. Overall, the proposed method represents a promising analytical tool for sarcosine quantification. The concept is also applicable for broader analytical applications in detecting other biomolecules.© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.