Ion Transport And Sensign Application Based On Functionalized Nanochannel

Biological nanochannels or nanopores play a crucial role in physiological activity by controlling the ion transport inlet and outlet of the cell,such as muscle contraction,photosynthesis,energy conversion,signal transfer,and regulating the system function.For the propose of understanding the working mechanism of biological nanochannels in physiological processes,a series of biomimetic nanochannels have developed based on techniques including nanotechnology,interface chemistry,and molecular biology in order to mimic the structure and function of biological ion channels,which is of great attention owing to their great importance in fundamental studies and further application.Based on the above mentioned research background,we fabricated some intelligent nanochannels with certain structure and function.Furthermore,their ion transport characteristics and application were explored.The main content of the dissertation are as follows:1.We fabricate a nanofluidic membrane with heterogeneous 1D/2D channel structure.The mixed-dimensional nanofluidic device features 1D channels of porous anodized aluminum oxide membrane modified with positive charge(AAM)and 2D channels membrane with opposite charges,which is self-assembled through vacuum filtration method with graphene oxide(GO)film covered by metal organic frameworks(MOF)nanoplates,termed GMM.Both the asymmetric geometry and surface charge of the 1D/2D nanofluidic device contributes the ion current rectification(ICR)property.When the electrolyte concentration was 10 m M,a maximum value of ICR ratio through the heterogeneous membrane was observed.By measuring the ion transport characteristics of the mixed membrane by varying wavelengths with a constant power density,we find that both the regulating range of rectification ratio and the conductance ratio before and after illumination have a maximum when the wavelength of illumination is 420 nm.Interestingly,the ionic conductance and rectification can be precisely and robustly modulated by visible light of 420 nm wavelength with different power intensity simultaneously.The excellent performance makes it a promising alternative for further applications in nanoconfined analysis.2.We have developed a highly sensitive and selective nanofluidic sensing device that detects subnanomolar streptavidin by modifying supramolecular DNA nanostructures in nanopores.The streptavidinrequiring aptamer was incorporated into the supersandwich structures using specifically designed probes.The formation of complex DNA nanostructures inside the nanopores efficiently blocked ion conduction.Thus,the presence of streptavidin could be identified by monitoring the change of ionic current in the nanopores as the confined space was further occupied.We achieved a reliable detection limit of 10 fmol/L for streptavidin.The bio-hybrid nanopore sensor had no response to hemoglobin or catalase under identical conditions.Thus we believe that the proposed strategy could be extended to detect some disease-related molecular targets and plays a considerable role in biotechnology.