| The ion transport across the cell membrane is essential to maintain normal cellular physiological functions and a variety of life activities.The liquid/liquid interface is considered to be the simplest model for simulating biofilms.The core issue about the liquid/liquid interface for electrochemical research is the kinetics and thermodynamics of charge(electron or ion)transfer processes.This field has achieved very rapid development in the past thirty years,and has potential application prospects in simulating biofilm function,studying drug release and solar energy conversion,and exploring chemical sensing mechanism,extraction process and phase transfer catalysis.The mesoporous silica material has the advantages of stable structure,large specific surface area,high porosity,and good biocompatibility.The pore surface can be modified with different biological functional molecules and chemical functional groups,and can also be used to simulate biofilm well.Therefore,the mesoporous silica can be employed to construct the micro-liquid/liquid interface to study the ion transfer process.It has important implications for understanding life phenomena,revealing the ion transmembrane transfer and metabolism processes in vivo.This paper mainly includes the following four parts: 1.The basic principles and theories in the mass transfer process in nanochannels are described.The electrode modified with vertically ordered mesoporous silica film and the electrochemical study at the liquid/liquid interface are briefly introduced.And we also discussed the type and mechanism of the charge transfer reaction at the liquid/liquid interface,as well as the construction methods of the micro-liquid/liquid interface,and the electrochemical techniques for research.2.In this chapter,the St?ber solution growth method was used to prepare vertically ordered mesoporous silica on ITO,which was treated as a silica nano-cavity array electrode.And the electrode containing surfactant micelles was labeled as MSNCA/ITO,the electrode without micelles is labeled SNCA/ITO.The pore size is approximately 2~3 nm,and the nano-cavity wall contains the group of-Si OH.Therefore,the p H value of solution has a great influence on its charge characteristics.The scanning electron microscope(SECM)was used to comparative study the selective permeability of three different charged redox pairs(Fe(CN)63-,Fc CH2 OH,Ru(NH3)63+)on the electrodes of MSNCA/ITO and SNCA/ITO respectively with a four-electrode system.Due to the charge effect of the nanochannels,the goal of regulating the selective penetration of ions and molecules was successfully achieved by controlling the potential of the tip and substrate and adjusting the p H value of the solution.3.In this chapter,the SNCA/ITO electrode was employed a new type of liquid/liquid interface nano-cavity array electrode for simulating the complex ion transfer processes in biological system.The SECM was used to detect the ion transfer current signals and good results were achieved.The p H and ionic strength of the aqueous solution could change the charge properties of the nano-cavity wall,so that the regulatory transfer of K+ and Na+ ions were achieved.Because of the different electrostatic interactions between different ions and charged regions in the nano-cavity,the SNCA/ITO electrode has more pronounced selectivity for the alkali metal ions with low electronegativity.4.In this chapter,3-aminopropyltrimethoxysilane(APTMS)was modified on the SNCA/ITO electrode,so that the amino group was present on the surface of nano-cavity.p H can regulate the degree of protonation of-NH2.Therefore,we have constructed a p H responsive nano-cavity electrode.And the regulatory ion transfer was studied by controlling the p H and changing the ionic strength of solution. |
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