Urea is an essential substance in biological species and the environment. It acts as an direction indicator for abnormal conditions of body and participates in the environmental system as a fertilizer which can penetrate into soil1. A molecularly imprinted polymer (MIP) electrochemical sensor was developed for the detection of urea with a high linear sensitivity, lower detection limit, and good selectivity2. Electrochemical, such as cyclic voltammetry (CV), were utilized to calibrate and improve the sensor. Additionally, urea was successfully determined in real blood serum samples for clinical diagnosis applications. In order to improve selectivity, Yarahmadi et al. demonstrated that the construction of double recognition aptamer could be combined with the original MIP electrochemical sensor. This improved sensitivity and specificity toward the quantitative analysis of urea in soil and water samples3. The aptamer greatly enhances the recognition of urea, which leads to excellent selectivity and sensitivity. In the stream of development, there is a new approach to implement so that efficient clinical diagnosis can be achieved by adjusting flexible properties of electrode unlike traditional rigid features4. This allowed for successful analysis of urea concentration in human sweat with acceptable sensitivity and selectivity, but promising insight in the applications of physiological diagnosis as noninvasive monitoring system for urea. The development of better analytical methods and the limitations we still face will be discussed.
1. Singh, M.; Verma, N.; Garg, A. K.; Redhu, N., Urea biosensors. Sensors and Actuators B-Chemical 2008, 134 (1), 345-351.
2. Chen, Y. P.; Liu, B.; Lian, H. T.; Sun, X. Y., Preparation and Application of Urea Electrochemical Sensor Based on Chitosan Molecularly Imprinted Films. Electroanalysis 2011, 23 (6), 1454-1461.
3. Yarahmadi, S.; Azadbakht, A.; Derikvand, R. M., Hybrid synthetic receptor composed of molecularly imprinted polydopamine and aptamers for impedimetric biosensing of urea. J Microchimica Acta 2019, 186 (2), 71.
4. Liu, Y.-L.; Liu, R.; Qin, Y.; Qiu, Q.-F.; Chen, Z.; Cheng, S.-B.; Huang, W.-H., Flexible electrochemical urea sensor based on surface molecularly imprinted nanotubes for detection of human sweat. J Analytical chemistry 2018, 90 (21), 13081-13087.