Construction Of Metal Phosphate Nano-enzyme And Monitoring Superoxide Anions Released By Living Cells

Superoxide anions play a very important role in the metabolic process of life.Under normal physiological conditions,the production and clearance of reactive oxygen species?ROS? in the body will maintain a dynamic balance.However,aberrant ROS concentrations are often associated with disease.High concentrations of ROS can cause oxidative damage to DNA and proteins,and even lead to cancer,cardiovascular disease,neurodegenerative diseases and aging.The rapid,reliable,sensitive,real-time and dynamic detection of superoxide anion is of great significance for related pathological research,disease diagnosis and health screening.However,due to the short half-life,high activity and easy reaction with other small molecules in the biological environment,it is very challenging to realize real-time dynamic detection of superoxide ions.Currently,the methods for detecting superoxide anion have been developed,but they are still inadequate.The electron spin resonance trapping method requires expensive equipment and corresponding trapping agents.Spectrophotometry is simple in operation and low in cost,but the detection limit,sensitivity and anti-interference ability need to be improved.Chemiluminescence is another method that is easy to operate and fast to detect,and can be used for trace analysis of reactive oxygen species.However,it needs to develop a special fluorescein.Fluorescence spectrophotometry can provide spatiotemporal information detection of intracellular target molecules,but the sensitivity and selectivity are insufficient.Compared with the above methods,the electrochemical analysis method is considered as the most promising method for the determination of superoxide anion because it can be used to detect superoxide anion rapidly and in real time in complex systems.However,in the electrochemical analysis method,the key to in situ superoxide anion detection is to construct a detection platform with biocompatibility,high catalytic activity and sensitivity.From transition metal phosphates in search for a simulated enzyme with a specific catalytic properties as active center,the use of the network structure of carbon materials and biocompatibility of building of natural polymeric materials have high catalytic activity,high sensitivity,good selectivity,sensing materials,structures,easy to spread and electrolyte live microenvironment of cell growth,to build an ideal sensor interface,in situ,real-time,dynamic and accurate detection of cells release superoxide anion this goal.The main contents are as follows:1.Potential biocompatible iron phosphate nanofibers were prepared by electrostatic spinning technology.In order to further improve the conductivity of iron phosphate and improve its microstructure,the flexible nanofibers were prepared by introducing rGO for three-dimensional mesh cutting and morphological regulation of carbon fibers.The electrochemical sensor constructed by the composite fiber is used for the detection of superoxide anions.Under the 0.5 V test condition,its sensitivity reaches 9.6?A·?M^-1·cm^-2,the minimum detection limit reaches 9.7 nM?3 times signal-to-noise ratio?,the response time is about 1.6 s,and the linear range is 10 nM?10?M.Because of its low detection limit and fast response time,it can be used for sensitive detection of superoxide anion released by cancer cells?HeLa?and normal umbilical vein endothelial cells?HUVEC?stimulated by drugs.2.In order to build an electrochemical sensing interface that is easy for cell adsorption and growth,shaggy microspheres woven by nanowires were prepared by using chitosan confined growth of nano-manganese phosphate.Its unique three-dimensional porous network structure,which is beneficial to the spread of the electrolyte,enchase 2?3 nM in microspheres manganese phosphate embodies the high catalytic activity,and chitosan itself provides excellent biocompatibility,therefore we design the sensor shows high sensitivity not only 1.6?A·?M^-1,a lower detection limit of 9.4 nm?S/N=3?,thus can be effectively used for detection of cells release superoxide anion.3.Through chemical and physical methods dealing with bacterial cellulose gel,stripping to turn it into a thin sheet of nano fiber network.Single strand DNA was combined with bacterial cellulose by hydrogen bond,and manganese ions were anchored to construct a graphene-like microsphere with two-dimensional planar structure curling.Its unique structure showed excellent electrochemical properties.The feasibility analysis of superoxide anion detection based on BC@DNA-Mn₃?PO₄?₂ sensor is discussed.