Development Of Nanoporous Material-based Electrochemical DNA Sensors And Their Applicat

DNA biosensors,which use the interaction between DNA molecules and target molecules to realize the specific detection of target molecules or biological processes,have important applications in the diagnosis and treatment of diseases.Among them,the electrochemical DNA biosensor has the advantages of simple operation,rapid response,low cost,easy miniaturization and so on.It is a biological analysis device with great application potential.Although electrochemical DNA sensors have their own unique advantages,they still face challenges in terms of sensitivity,resistance to biological contamination in complex biological samples,and versatility in detecting major types of biomolecules.Nanoporous materials that match the size of biological macromolecular structure play an important role in the field of biological sensing.Nanomaterials and nanostructure can provide a variety of functions and help to improve the performance.Among all nanoporous materials,nanoporous gold(NPG)has shown great potential in the design and construction of high-performance multifunctional DNA biosensors due to its tunable double-continuous porous structure,good biological compatibility,easy modification of surface chemical properties and excellent electrochemical properties.At present,the research of NPG in the field of biosensor mostly belongs to the technical application,while the underlying molecular motion law and other basic research are rarely involved.This greatly limits the high-end applications of NPG in the field of biological sensors.In this paper,a general NPG biological sensing platform was constructed to study the transport response of methylene blue(MB)and MB modified DNA molecules.Moreover,the application of the NPG sensing platform in biological analysis was investgated.The main content is as follows:(1)Construction of a general NPG sensing platform based on DNA diffusion differences.Firstly,the influence of the length of DNA molecule on its transport in NPG was systematically studied.Then,the intrinsic structure-activity relationship and mass transport law were explored through difusion kinetics simulation.Based on the systematic study and full understanding of the structure-activity relationship,a specific scheme was designed to detect and analyze the DNA residues after the action of nuclease to evaluate the activity of nuclease.Finally,the constructed NPG electrochemical sensing platform was combined with the nuclease-assisted DNA homogeneous recognition and amplification reaction to develop highly sensitive,highly selective and anti-interference DNA sensors to realize the sensitive detection of DNA and microRNA.(2)Controllable release and enrichment of methylene blue based on nanoporous materials and its bioanalytical applications.First of all,the DNA gated mesoporous silica microspheres loaded with MB were prepared(MB@MSN-A-DNA/Aptamer)was prepared.When there is AFP,AFP can competitively combin with the Aptamer on MB@MSN-A-DNA/Aptamer,open the "door",and release the MB.The addition of RecJf enzyme in this process can not only achieve the cyclic utilization of the target,but also hydrolyze A-DNA,so that MB can be released more quickly and easily.Based on the systematic study and full understanding of the structure-activity relationship in scheme design(1),NPG was functionalized with G4-DNA to enrich MB more efficiently and quickly.Finally,the functionalized NPG sensing platform can realize effective enrichment of MB molecules and detect AFP with low background and high sensitivity.The linear range of AFP detection is 100 fg/mL-100 ng/mL,and the detection limit is 10.2 fg/mL.