Supramolecular System Involved Nano-pore/channels For Detection Of Small Molecules

Nano-pore/channel sensor has attracted wide attention due to its simplicity and practicability.After more than 20 years of development,nano-pore/channel technology has become the most promising molecular sensor detection technology.There are two detection methods based on artificial single nano-pore/channel: resistance pulse method and ion rectification method.By using this technology,we can successfully detect the complexes of various small molecules,organic polymers,proteins,enzymes and biomolecules.Due to the limitation of time resolution of nano-pore/channel materials and instruments,the preparation,functional modification of nano-pore/channel and their detection of small molecules have certain challenges.In this thesis,supramolecular host-guest involved nano-pore/channel for detection of small biological molecules is systematically studied by combining the related properties of supramolecular host-guest chemistry with nano-pore/channel analysis.It is mainly divided into four parts:(1)The selective and quantitative detection of melamine was realized by using the functional single conical nanochannel sensor.The melamine detection platform was constructed by ?-cyclodextrin,melamine aptamer and single-walled carbon nanotubes.This paper mainly analyzes the changes of ion rectification before and after the detection of melamine by ion current-voltage test,so as to explore the performance of nanochannel sensor in melamine detection.In this study,the nanochannel sensor constructed with the assistance of multi-component materials can realize the selective quantitative detection of melamine.There is a good linear relationship between melamine concentration and surface coverage in the wide concentration range of 0-200 nM,and the detection limit is 4.3 nM.At the same time,the nanochannel sensor also has good stability and the potential of practical sample detection.(2)Based on the host-guest competitive interaction,nanochannel sensor was constructed to realize the selective quantitative detection of adamantamide.Through the introduction of host guest molecules p-toluidine and cucurbit[7]uril into the single conical shaped nanochannel,the hydrophobicity and surface charge of the nanochannel changed under the stimulation of adamantamide based on the host guest competition.The change curve of ion rectification with adamantamide concentration was obtained by ion current-voltage test.The results show that the detection system has good stability and repeatability,and can realize the selective quantitative detection of adamantamide.In the wide concentration range of 10-1000 nM,there is a linear relationship between the logarithm of ADA concentration and the surface coverage rate,and the detection limit is 4.54 nM.At the same time,the nanochannel sensor also has the potential of practical sample detection.(3)Based on the host-guest competitive interaction,the host guest stimulus response nanochannel was constructed.By introducing host guest molecules(p-toluidine and cucurbi[7]uril)into the straight nanochannel,under the stimulation of the guest molecule(adamantamide)and host molecule(cucurbit[7]uril),the nanochannel can realize the function of reversible molecular stimulation response switch,and has good repeatability and stability.This work provides a reference model for the further study of the action of adamantamide in organisms.(4)By using supramolecular nucleic acid nanostructures(nucleic acid tetrahedrons)as signal amplification probes,a new strategy for the detection of small molecules by nanopores was developed.In this study,we compared the via signals of four different nucleic acid nanostructures and the detection experiment of ATP small molecules by using nucleic acid tetrahedron as signal amplification probe assisted glass nanopore,which showed the advantages and feasibility of DNA tetrahedron as the signal amplification probe to assist the nanopore to realize the small molecule detection.Through the research of this thesis,the method of combining supramolecular system with nano-porechannel detection is proposed,which realizes the functional diversity of nano-pore/channel and the detection of biological small molecules,and provides a new opportunity for the further development of nanopore in small molecule detection.