Preparation Of Biocompatible Conductive Polymer Hydrogel And Its Application In In-situ Cell Electrochemical Sensors

The development of in-situ cell electrochemical sensors can provide important value for disease diagnosis,drug development,drug side effects research and other fields.The main advantage of in-situ cell electrochemical sensor is that the cell adheres to the sensing electrode,so that the active molecules released from cell can be captured by the electrode immediately,thus shortening the response time and improving the accuracy of detection.However,how to develop sensing electrode materials with excellent biocompatibility,matching mechanical properties,high conductivity and high selective catalysis is still a huge challenge.Conductive hydrogels may be one of the most potential materials to solve this problem,mainly because the conductive hydrogel combines the characteristics of hydrogel and conductive material:high water content,similar physical properties with extracellular matrix,good biocompatibility,matching elastic modulus and electrical conductivity.However,up to now,there are still many problems in the development of conductive hydrogels,such as low electrical conductivity,harsh preparation conditions（high temperature treatment）,toxic and harmful reagents（sulfuric acid,a large number of metal ions）,complex process and time consuming.In response to the current scientific problems in this field,this thesis proposed and developed a conductive polymer hydrogel with excellent biocompatibility,high conductivity,and efficient selective catalysis,which is used in the construction of in-situ cell electrochemical sensors.The main content and results are summarized as follows:1.To solve the problem of poor biocompatibility of classical polyaniline/phytic acid conductive hydrogels reported in the literature,we have explored a material with high conductivity and excellent biocompatibility,PEDOT:PSS,as a cross-linking agent for the preparation of conductive hydrogels to replace the cross-linking agent with poor biocompatibility.The experimental results show that the conductive polymer/PEDOT:PSS hydrogel has good biocompatibility,and the conductivity is 10-15 times higher than that of the traditional conductive polymer/phytic acid hydrogel.Electrochemical sensing of dopamine and hydrogen peroxide was carried out based on the conductive polymer/PEDOT:PSS hydrogel.Based on conductive polymer/PEDOT:PSS hydrogel,an in situ cell electrochemical sensor was developed for the detection of active molecules dopamine and hydrogen peroxide released from cells,and showed excellent electrochemical sensing properties,good biocompatibility and matching mechanical properties.2.To solve the problem of poor biocompatibility of PEDOT:PSS hydrogel due to harsh preparation methods,the use of toxic and harmful reagents,and insufficient environmental protection,we have developed a new PEDOT:PSS hydrogel method system with PEDOT:PSS as the main body and conductive polymer as the crosslinking agent.The preparation method was simple and easy to operate.The experimental results showed that this PEDOT:PSS hydrogel possessed better biocompatibility than various PEDOT:PSS hydrogels reported in the literature.At the same time,this type of hydrogel have high electrical conductivity(>1100 S m^-1).An in situ cell electrochemical sensor based on PEDOT:PSS hydrogel were developed for the detection of the active molecule dopamine released from PC12 cells,and showed excellent electrochemical sensing properties,good biocompatibility and matching mechanical properties.3.To develop a 3D cell culture electrochemical sensor platform with excellent biocompatibility,we prepared PEDOT:PSS conductive hydrogel with non-toxic hydrogen peroxide as an oxidant,and then successfully prepared a three-dimensional PEDOT:PSS scaffold electrode by freeze-drying method.The experimental results showed that cells could migrate,adhere and grow in the 3D porous structure of the PEDOT:PSS conductive scaffold.An in situ cell electrochemical sensor based on PEDOT:PSS three-dimensional electrode was constructed for the detection of active molecule hydrogen peroxide released from Hep G2 cells,and showed excellent electrochemical sensing performance,good biocompatibility,matched mechanical properties and three-dimensional cell culture ability.