Investigation Of Supramolecular Functionalized Quartz Glass Nanopores And Molecular Detection

With the fast development of nano science and technology in recent years,the sensor is designed based on the pore become the key tool in the field of sensing detection,quartz glass nanopores as a very important branch of nanopores,has been applied to DNA,protein and a variety of single molecule detection,has become the modern biological and chemical sensing is one of the frontier technology in the field of analytical chemistry,A key feature of the technology is that it does not require any complex and expensive equipment,and each nanopore can be easily and cheaply prepared,thus reducing the cost and turnaround time.And with the latest progress of material science and surface chemistry,quartz glass nanopore has become a nano-sensor with higher sensitivity becomes possible.The main analysis and sensing methods of nanopore are based on ion current resistance pulse sensing technology and ion rectification sensing technology.At present,the application of nanopores in sensing based on ion rectification technology is generally functionalized by modifying specific groups,and then functionalized quartz nanopores can be used to identify analytes of different sizes,shapes and charge densities.However,the current methods of functionalizing nanopores require complicated steps,require multi-step chemical reactions or expensive metal deposition,at the same time,the materials used for functionalizing nanopores are single,and the response current signal of nanopores is weak,which limit the specific recognition of molecules and achieve higher sensitivity of nanopores.However,supramolecules have a great influence on the development of sensing and detection due to their unique rigid cavity structure that can selectively recognize guest compounds.Therefore,in this study,supramolecular hybrid materials were constructed in quartz glass nanopores by chemical modification,forming a nanopore system functionalized by supramolecular hybrid materials,so as to identify molecules by using the hoest-guest properties.The research content mainly includes three parts:Ⅰ.Quartz glass nanopores were functionalized by chemical modification of silane molecules with amino groups.Then,pillar [5] arene(CP[5]),leaning pillar [6] arene(CLP[6]),pillar [5] arene modified gold nanoparticles(CP[5]-Au NPs)and leaning pillar [6]arene modified gold nanoparticles(CLP[6]-Au NPs)were fixed on the inner wall of nanopores by crosslinking reaction of amide condensation.Transmission electron microscopy(TEM),field emission scanning electron microscopy(SEM),infrared spectroscopy and contact Angle,XPS and other characterization methods were used to confirm the successful construction of the functional nanopore system.At the same time,the changes of ICR state in the nanopore during the modification were recorded by electrochemical I-V curve to characterize the process of functionalization.Finally,four kinds of functional nanopores were used to detect pesticide molecules by using supramolecular host and guest properties.The recognition and selectivity of four kinds of functional nanopores for pesticide molecules were studied by I-V curve and normalized ion current change rate response.The results showed that CP[5]-Au NPs functionalized nanopores had the best detection performance for paraquat molecules,and the detection limit reached 0.73 n M.II.In order to further improve the detection performance of CP[5]-Au NPs functionalized nanopores for paraquat molecules,the size effects of CP[5]-Au NPs and nanopores,as well as the effects of different p H and scanning speed on the detection of pesticide molecules were studied.At the same time,several metal ions and pesticide molecules were added to evaluate the anti-interference ability of functional nanopores.Finally,the functional nanopores were put into different water samples,apple peel and tea extracts to test the real samples.Experiments show that the 3 nm-CP[5]-Au NPSfunctionalized 70 nm nanopore sensor has strong anti-interference ability and high selectivity,and can also detect low concentration of PQ molecules in different real samples.This provides a possibility to develop fast,stable and specific PQ sensor designs that can adapt to different real environments.III.Based on a similar functionalization approach,nanopores functionalized by gold nanoparticles(CB[7]-Au NPs)modified by another supramolecular,cucurbit [7] uril,were designed.The best CB[7]-Au NPs material was selected by transmission electron microscopy(TEM),UV spectrum and Zeta potential.The optimal CB[7]-Au NPs were used to functionalize the nanopores.Infrared spectroscopy,contact Angle,XPS and other characterization methods were used to confirm the successful construction of the nanopores.Subsequent tests on four kinds of amino acid molecules in the recognition,by comparing the ion current rate evaluation of functional nano holes on four different amino acid molecules recognition ability,found the functionalization of nanopores concentration of these amino acid molecules can be accurately detection,detection limit has reached the level of skin Moore,detection of benzedrine acid has the most excellent performance.