The Study Of In Vivo Electroanalysis Based On The Ion Current Rectification In Functionalized Micropipette

The ion current rectification(ICR),as a popular research point in recent years,is defined that the absolute value of current signal on one polar voltage is higher than the other current on an opposite polar voltage.I-V curve of ICR is similar to the curve of solid-diode.Based on the recognition of ICR,we get key points of causing the ICR,such as the pipet shape,the wall charge density,electroosmotic flow,scan rate,pressure,et.,which can promote and obstacle the immigration of the ion in the micropipete.The migration of ion will be encouraged and discouraged by inner wall charge in the micropore.Thus,in the all,the reason of ICR appearing is much related with asymmetrical distribution of ion.The existed in vivo electroanylisis methods are built on the in situ analysis method of in vivo and the online analysis method of in vivo,which were limited to detect substance in electrochemical activity.The general idea of this article based on functionalized micropipette,designing and developing a new strategy sensor creats unique advantage in vivo with ICR that has high selectivity,sensitivity and can be used for non-electrochemical activity detection,.The main progress is as follows:(1)The research of micropipet ICR based on Pvim.For the previous research,there is single result with PimB modified on inner wall of micropore,which cannot show the influence of the surface charge density in the ICR.So,the work tries to modify Pvim onto wall of micropipette.Pvim can carry different charge at different pH solution,when changing the pH can research the influence of the surface charge density in ICR.The work also researches the influence of the stability,reversibility and different scan rate in ICR,and uses three layers theory to explain the ICR of Pvim modified micropipette.The perfection of the ICR model will bring out more reference for application.(2)pH sensor based on micropipet with Pvim.Through Pvim modified electrode that has good pH responding in acsf with detailed research.So,we can design a micropipet electrode modified by Pvim for p H detection in the rat brain.However,the traditional method with cyclic voltammetry for ICR detection has a low temporal resolution.As the result,the work designs a new kind of the voltage-controlled and high temporal resolution method for pH detection in vivo.The electrode has good stability,repeatability and selectivity.And the sensitivity of pH can get 0.1 pH fluctuation.We use the CO2 for brain oxygen-poor model,and find the electrode has good sensitivity and high temporal resolution in pH sensing of rat brain.(3)ATP sensor based on ICR in imidazole functionalized micropipet.Modified the PimB onto the inner wall of micropipette that can get one electrode with the ICR,and then,absorbing ATP aptamer onto the inner wall of micropore.The ATP molecule can be recognized by the dual recognition unit consisting by PimB and ATP aptamer.At last,the biosensors will be used for ATP detection in rat brain.The PimB modified electrode with the ICR has suitable range for ATP detection,it can exclude the physiologically reactive substance and ATP analogue and has high selectivity.This new kind of ICR electrode solves the problem that the ATP can be exacted detection in complex rat microdialysis.