PANI nanofibers oxidized by FeCl3 were employed as the supports for the immobilization of horseradish peroxidase (HRP) via covalent immobilization.These PANI-HRP enzymes have been characterized using scanning electron microscopy (SEM)

Fourier transform infrared (FTIR) spectroscopy and UV-Visible spectroscopy.SEM images show that the diameters of PANI-nanofibers are in the range of 20~30 nm.The nanofibers become larger and rough after immobolization of HRP.FTIR and UV-Vis demonstrate that horseradish peroxidase can dope into PANI supports as the dopants.This method is simple

fast

and the activation of PANI support is not necessary.The maximum amount of HRP loading on PANI is 150 g/mgPANI for undoped-PANI

90 g/mgPANI for doped-PANI

respectively.Comparing with the free HRP

the optimum working pH

the optimum working temperature and thermal stability of PANI-HRP were significantly improved.No obvious activity loss was observed after 7 weeks storage at 4 ℃

and 80% of the initial activity could still remain even after 6 times usage.These results demonstrate that PANI nanofibers as a carriers for HRP enzymes have great potential applications.