Fabrication Of Carbon Nanofiber Based Working Electrode And Its Dection Performance For Uric Acid In Artificial Sweat

Gout has become a very common arthritic on account of unreasonable diet and excessive eating habits.Gout occurs at irregular times and is almost alwalys accompanied by excruciating pain,which makes the sufferers miserable.In addition to diet control,prevent and treatment of gout require prolonged uric acid monitoring.With the development of portable medical devices,the real-time monitoring of various biomarkers related to health has attracted people’s attention.Traditional medicine often requires blood samples and cumbersome instruments to detect biomarkers,which is invasive and complex.In contrast,sweat sensors based on sweat analysis have a promising future in personalized medical devices due to their non-invasive approach and real-time monitoring characteristics.Sweat,a liquid secreted by sweat glands,is rich in biomarkers(such as glucose,lactic acid,uric acid,K~+,Na~+,etc.),which are closely related to the physiological status of the human body and can reflect the health status of the human body.It is a significant choice to monitor the trend of blood uric acid concentration through detecting the uric acid in sweat.Unlike temperature and humidity sensors,sweat sensors need to be in contact with the skin,so the selection of substrate material for sweat sensors is a point that cannot be ignored.Most of the traditional sensor substrates are thin film flexible substrates,and the electrode materials are processed onto the substrates by complex means.In this study,the flexible and conductive carbon fiber film obtained by stabilization and carbonization was prepared by electrostatic spinning technology and attached to the commercial screen-printing electrode to detect uric acid in artificial sweat.The influence of stabilized temperature and time on the extent of stabilization was investigated.In the air atmosphere,the best process of stabilization was to raise the temperature from room temperature to 280°C at a rate of 5°C/min and keep the temperature for two hours,with the extent of stabilization reaching 99.7%.Through XPS,Raman,four-probe tester,etc.,the influence of the internal structure and element composition of carbon fiber on the conductivity is clarified.Among the carbon fiber prepared at three carbonization temperatures of 800°C,900°C,and 1000°C,the carbon fiber membrane prepared at 1000℃has more graphitization degree,higher content of carbon elements and the best conductivity.The carbon fiber membrane was attached to the commercial screen-printing electrode for electrochemical test.The feasibility of uric acid detection by the electrode was analyzed.The standard diagram of uric acid detection was drawn by regulating uric acid concentration in artificial sweat.It was found that there was a good linear correlation between the gradient concentration of uric acid detected by the base electrode at CNF-900°C and CNF-1000°C.The linear correlation R~2 was 0.993 and 0.997,respectively.The fiber-wire-based electrode sensor prepared in this study has a simple preparation process and good sensitivity linearity,which is suitable for the detection of uric acid in sweat by electrode materials as sweat sensors.