The Construction Of The Sensing Platform Based On Cotton Carbon Fiber Composites And Study On Oxidative Stress Of Cells

Superoxide anion(O2·-)is one of the typical representatives of reactive oxygen species(ROS),and its dynamic changes can provide abundant physiological and pathological information.Therefore,the highly sensitive and accurate detection is of great significance for the early diagnosis and prevention of related diseases.Nitrogen-doped cotton carbon fiber(NCF)not only retains good electrical conductivity and other electrochemical properties,but also has a large specific surface area and a large number of oxygen-containing functional groups,so it can be used as an effective load matrix.Based on the excellent electrochemical performance of nitrogen-doped cotton carbon fiber and the strong catalytic performance of silver nanoparticles(AgNP),a highly sensitive superoxide anion electrochemical sensor was constructed and used to monitor the release of O2·-in living cells in real-time.The main contents of the study are as follows:1.Firstly,nitrogen-doped cotton carbon fiber(NCF)was prepared by using defatted cotton and urea under optimized conditions.Then silver nanoparticles(AgNP)were electrodeposited on the surface of NCF modified electrode and a new electrochemical sensor was constructed.The AgNP/NCF composite combines the excellent conductivity of NCF and the excellent catalytic performance of AgNP,so the performance of sensor based on AgNP/NCF composite is very excellent.The detection limit of superoxide anion is as low as 2.32 × 10-15M,and the linear range is as wide as 10 orders of magnitude.We used AgNP/NCF/GCE to monitor the release of O2·-in cells under normal and oxidative stress.More importantly,we have further studied the ability of antioxidants to eliminate superoxide anions,providing a new strategy for preventing oxidative stress-related diseases.2.Based on the previous part of the experiment,we used a simple chemical reduction method to prepare small size and dispersed uniform silver nanoparticles(AgNP),which were combined with nitrogen doped cotton carbon fiber(NCF)to form NCF-Ag nanocomposites.A novel electrochemical sensor was constructed for the detection of superoxide anion(O2·-)released from cancer cells.Due to the good electrocatalytic activity of silver nanoparticles and the advantages of nitrogen doped cotton carbon fiber with large specific surface area and excellent electrical conductivity,the electrochemical sensor has good performance.It has wide linear range for 02'-(7.59 ×10-14?7.22 ×10-5M)and low detection limit(2.53 × 10-14M).More importantly,the sensor was successfully used for in situ monitoring of O2·-release from glioma cells(U87)under normoxic and hypoxic conditions,and further explored the effect of antioxidants on the repair of hypoxic cell injury.