The application of DNA nanotechnology to trace water environmental pollution

Water pollution is one of the most severe challenges to human society, which seriously hinders the sustainable development of global ecological environments and social economy. It is extremely difficult to trace the pollution source, determine the pollution scope and quantify the pollution degree, due to the large number of potential pollution sources and the complexity of hydrogeological processes. To address these challenges, a variety of tracer systems for water environmental pollutants have been developed, including ions, dyes, microorganisms, stable isotopes, etc. The application of these tracer systems has played an important role in promoting the treatment of water environmental pollution, which is of great significance for improving the water ecological environment. However, these traditional tracer systems still exist many limitations, such as strong environmental background noise, limited quantity, uncontrollability, low detection sensitivity, etc. There is an urgent need to develop new and robust tracer systems. In recent years, the rapidly developing tracer system (DNA tracer system) based on deoxyribonucleic acid (DNA) nanomaterials is gradually emerging, which uses DNA fragments as specific markers to trace hydrological pathways and water environmental pollution. Compared with the existing tracer systems, the DNA tracer system has many outstanding advantages, such as large quantity, strong specificity, sensitive detection, stable and controllable migration and degradation, and environment-friendly. It is a promising new generation of tracer systems. However, the development and application of the DNA tracer system involves multi-disciplinary knowledge such as biochemistry, materials science, environmental engineering and hydrogeology, which is a typical cross-research field. Therefore, the application of the DNA tracer system usually requires adequate interdisciplinary knowledge. This undoubtedly increases the difficulty of its application. In order to promote the further development of the DNA tracer system and enhance the prevention and treatment ability of water environmental pollution, this review focuses on the principle and method of DNA fragments as tracers for water environmental pollution, highlights three main advantages of the DNA tracer system compared to traditional tracer systems, comprehensively reviews the development of the DNA tracer system since 1995, and summarizes the typical application of the DNA tracer system in the study of water environmental pollution. Finally, the important research directions in the future are prospected. These research directions include the optimization design of DNA base sequence, simplification and standardization of DNA tracer fabrication, characterization of DNA tracer transport in surface and underground water, application strategy of DNA tracers under complex water environments, and combined application scheme of DNA tracing technology and other technologies. Despite nearly 30 years of development, the DNA tracer system is still in its infancy stage, and further understanding of the structural properties of DNA nanomaterials and its molecular mechanism for analysis of environmental pollution is needed. The development of DNA tracers is a useful addition to the tracer family, which is also of positive significance for better identification of pollution risks in water environments. We believe that the DNA tracer system will have a broad development prospect in the future.