Herein we report a novel electrochemical sensing chip and a point-of-care device (PoC) for enzyme-free electrochemical detection of urea in human blood. The electrochemical sensing chip was developed by 3-D printing of conductive Ag ink and subsequent electrodeposition of AuNP-rGO nanocomposite. Material characterization of the sensing chip was conducted to find a plausible mechanism for the electrochemical reaction with urea. Subsequently, the response with varying concentrations of urea in solution and human blood samples was tested. High peak response current (~5 times than that of the highest reported value), low impedance, rapid sensor fabrication procedure, high selectivity towards urea, excellent linear response (R² = 0.99), high sensitivity of 183 μA mM⁻¹ cm⁻², the fast response indicated by high diffusion coefficient, the limit of detection of 0.1 µM, tested shelf life of more than 6 months and recovery rate of >99% ensured the application of the developed sensor chip towards PoC urea detection test kit. A PoC device housing an electronic circuitry following the principles of linear sweep voltammetry and compatible with a sensing chip was developed. A maximum percentage error of 4.86% and maximum RSD of 3.63% confirmed the use of the PoC device for rapid urea measurements in human blood.

在此，我们报告了一种新型电化学传感芯片和即时检测装置 (PoC)，用于无酶电化学检测人体血液中的尿素。电化学传感芯片是通过导电银墨水的 3D 打印和随后的 AuNP-rGO 纳米复合材料的电沉积而开发的。对传感芯片进行材料表征，以找到与尿素发生电化学反应的合理机制。随后，测试了溶液和人体血液样本中不同浓度的尿素的反应。高峰值响应电流（约为最高报告值的 5 倍）、低阻抗、快速传感器制造过程、对尿素的高选择性、出色的线性响应 (R ²  = 0.99)、183 μA mM ^-1 cm的高灵敏度^{- 2}，高扩散系数所显示的快速响应，0.1 µM的检测限，超过6个月的测试保质期和> 99％的回收率确保了开发的传感器芯片在PoC尿素检测试剂盒中的应用。开发了一种包含电子电路的 PoC 设备，该设备遵循线性扫描伏安法原理并与传感芯片兼容。4.86% 的最大百分比误差和 3.63% 的最大 RSD 证实了 PoC 设备用于人体血液中的快速尿素测量。