ELECTROCHEMICAL BIOSENSORS FOR CONT­ROL OF LEAD CONTENT IN THE ENVIRONMENT. A REVIEW

The review presents different types of biosensors and their principles of operation that are currently used to detect heavy metals and lead. Biosensors are considered highly sensitive, specific, accurate, inexpensive and effective tools for the preliminary detection of one or more metals in sources of mixed pollution, especially in wastewater. The use of functional nanomaterials based on metal-organic frameworks and layered hydroxides allowed to miniaturize the design of biosensors and significantly improve their applicability for on-site analysis of target samples, which reduces the probability of any changes in the samples during transport to the laboratory. Also, these materials have long-term stability, improve the signal and response speed of electrochemical biosensors, and also increase their sensitivity and selectivity. An overview of the methods of manufacturing the active component of multilayer electrochemical sensors was conducted. The main methods of obtaining stable and sensitive to lead ions electrochemical systems are noted.Sensors and biosensors are powerful tools for accurate qualitative and quantitative analysis of a specific analyte and integration of biotechnology, microelectronics, and nanotechnology to fabricate miniaturized devices without loss of sensitivity, specificity, and cont­rol accuracy. The characteristic properties of biomolecule carriers significantly affect the sensitivity and selectivity of the device. The impact of carriers based on metal-organic frameworks and layered hydroxides on increasing the efficiency of modern lead biosensors due to the implementation of the enzyme inhibition mechanism was considered, and the me­thods of manufacturing the active component of multilayer electrochemical sensors were also reviewed. The perspective of using the coprecipitation method and the ion exchange method to obtain stable and sensitive lead ion electrochemical systems was noted. Thus, electrochemical biosensors can be considered as one of the most widely developed biosensors for the detection of lead ions, in which the presence of direct electron transfer from the recognition center to the electrode reduces the probability of unnecessary interference, which significantly increases their sensitivity and selectivity and enables the development of devices for in-mode monitoring real-time.