Electrochemical Biosensors For Detection Of Uranium Based On The Specific DNAzymes

In the past half-century, uranium has been concentrated and widely used innuclear power plants、missiles、nuclear weapons and so on. Its usage is likely to growas an important energy source. Since, uranium is a naturally occurring radionuclidethat exists ubiquitously in the environment; human beings have a high chance ofbeing exposed to uranium, which related adverse health effects. The uranyl ion (O₂²⁺)is the most stable chemical form of uranium in water, which is also highlybioavailability to pose the greatest risk to human health, such as radiation and kidneydamage. The present study based on the specific recognition of DNAzymes for theuranium, to achieve a suitable electrochemical biosensor for analytical detection ofuranium, and establish the appropriate detection method, to achieve simple, fast,on-site, real-time detection and quantification of uranium.In this study, the subject is electrochemical biosensors for detection of uraniumBased on the specific DNAzymes，the detail materials are summarized as follows:1. The DNAzyme was immobilized onto the surface of the Au electrode via athiol-Au interaction, then the substrate and the DNAzyme were assembled onto thesurface through a hybridization reaction that constructed on a Au/ADNA/MCH/TDNA electrochemical biosensor. The DNAzyme was constructed by labelingelectroactive Fc, which was using [Fe（CN）₆]^3-/4-as transferred electrons to theelectrode surface. Optimizing the experimental conditions and using cyclicvoltammetry （CV） and electrochemical impedance spectroscopy （EIS） on the sensorin order to build Characterization of modified electrode, the experimental resultsdemonstrate that the sensing interface has been fabricated successfully, which can beused to detect O₂²⁺Based on the specific DNAzymes. 2. Based on the principle and design of the O₂²⁺sensor and optimizing theexperimental conditions, the sensor was used to analyze O₂²⁺with differentconcentrations. It is show that, the electrochemical biosensor had a dynamic rangefrom2nmol/L to14nmol/L with a detection limit of1nmol/L. The linear equationwas y=3.147x+0.501with a correlation coefficient of0.992. Comparing with othermetals, the sensor exhibited a response only in the presence of O₂²⁺, indicating thatthe sensor has excellent selectivity.In conclusion, the study shows that a promising technique for a simple, fast,on-site, real-time electrochemical biosensor for the detection of O₂²⁺Based on thespecific DNAzymes. The detection method has a higher sensitivity and selectivity forO₂²⁺. Contemporary, it also serves as a guide in choosing different methods fordesigning electrochemical sensors for other metal ions.