Electrospun Fibers With Enzyme Imobilized For Alcohol Concentration Detection

Nanofibers with small diameter, remarkable surface area, high porosity and controlled pore size, can be used to immobilize enzyme or other bioactive molecule through covalent or absorption. It can be used to monitor environment, food detection, and clinical diagnosis with the advantages of high sensitivity, fast response, stable results and reuse ability. In our study, polystyrene with amino-group was obtained through the nitration and reduction of polystyrene. Polystyrene nanofibers was made through electrospinning, followed by immobilization of alcohol oxidase (AOX) on the nanofiber mats through covalent bonding with glutaraldehyde. The detection of alcohol was carried out through the fading of nanofibers as the fade ability of H2O2which was generated by the oxidation of alcohol with the existence of AOX.After nitration and reduction by sulphuric acid and stannous chloride,17%benzene ring of the polystyrene was grafted with amino-group. Nanofibers with a good morphology were obtained with a diameter of about400nm and amino-group density of about235nmol/g. The immobilized enzyme, with the recovery activity of about49%, has good thermal stability, pH stability and about60%residual activity after reusing for15times. The nanofibers was dyed with indigo Carmine, and then the nanofibers were faded by H2O2generated by alcohol oxidation. The alcohol concentration was judged by the different fading degree of dyed nanofiber mats. As the color of nanofibers changed greatly with different alcohol concentration, a quantitative change curve was obtained with the blue color density. The blue color density changed from151to1as the concentration of alcohol changed from0to1.0mg/ml. According to the rules, the drunk driving and highly drunk driving was defined as the alcohol concentration of0.2mg/ml and0.8mg/ml, respectively. And then we use the fiber mats to detect the alcohol concentration of saliva and blood. The blue density changed from151to84as the alcohol concentration was0.2mg/ml, and the blue density changed from151to25when the alcohol concentration was0.8mg/ml. The obvious change can be seen with naked eyes. As a result, the nanofiber mats with AOX immobilized can be used to detect alcohol concentration easily, quickly and accurately. This method can not only be used by police officers to detect alcohol concentration, but also can be used to self-detection for drivers. Self-detection has good effect in reminding the driver not to drive after drinking. The characteristics of this detection method are cheap, simple, precise and practical.