Construction Of Visible Light-induced Renewable Electrode For The Detection Of Cell-released Nitric Oxide

In recent years,with the development of nanomaterials science and micro-machining technology,further modification and functionalization of bare electrode endows the electrode with numerous properties,such as high-selectivity,high-sensitivity,high temporal-spatial resolution,biocompatibility.And finally the electrode can be used for the detection of small molecules,cells and living organisms.However,electrode is easily fouled by some reaction intermediates or proteins,which hinder the electron transfer,bring down the electrochemical performance and increase the cost of testing.To date,the ways to get the issue solved can be divided into two classes.One is to prevent the deposition of pollution,such as the design of electrode with porous structure or the modification of anti-fouling materials.The other way is to clean the electrode by using physical method,chemical/electrochemical treatment,photocatalytic method.Compared with UV photocatalysts,visible light photocatalysts can degrade the pollutant by active oxygen species generated under irradiation.And at the same time,it possesses the advantage of less damage to the biological tissue.However,considering the photocatalytic efficiency,conductivity and electrochemical activity,visible light-induced renewable electrode for the "on line" cleaning has not been reported.So,based on these problems and our previous work,we constructed the visible light-induced renewable electrode and had been applied to cell culture and detection circularly.Then this renewable electrode was further modified to come true the bifunctional characters,that is renewing the fouling from small molecules and resisting the absoption of large protein molecules respectively.Furthermore,the new electrode accomplished cell culture and electrode cleaning simultaneously.The main works are presented as follows:1.Inspired by the visible-light photocatalytic performance of TiO2/CdS and the excellent electrochemical properties of PEDOT,we constructed the visible light-induced renewable PEDOT@CdS/TiO2/ITO electrode by electrophoretic deposition,successive ionic layer adsorption and reaction(SILAR),electrodeposition method gradually.The TiO2/CdS heterojunction structure facilitated the electron-hole separation,reduced the recombination of electron-hole pairs and thus enhancing the visible light photocatalysis.PEDOT coating provided a perfect biosensing interface and endowed the electrode high sensitivity(23.4 ?A/?M cm2)and low detection limit(3.4 nM).And ultimately,the electrode was used to monitor the nitric oxide(NO)release from HUVECs as well as subsequent visible light-induced regeneration of fouled electrode for reutilization.2.Combined with the above work,gelatin interacted with transglutaminase crosslinker was modified to the PEDOT@CdS/TiO2/ITO electrode to form gelatin-PEDOT@CdS/TiO2/ITO electrode by spin-coating method.When we manipulated the gelatin with ca.2 ?m thickness,the electrode can maintain electrochemical activity excellently.Due to the network structure of gelatin,on the one hand,it can diminish the protein absorption,on the other hand,it can still degrade the small pollutant in the visible light irradiation.What is more,the cytocompatibility of the gelatin ensured the cell viability and proliferation capability.Most importantly,the gelatin layer blocked the diffusion of reactive oxygen species into the cell surface during the photocatalytic process,and the damage to the cells decreased significantly.Finally,these features allowed "on line" cleaning in the process of cell culture and real-time monitoring of NO release.