HRP Immobilized On Polyimide Nanofiber Membrane:Effects Of Carbon Nanotubes And Porphyrin

Horseradish peroxidase (HRP) is one of the most widely studied peroxidases. Mutiwalled carbon nanotubes (MWCNTs) display electrocatalytic activities, and they have extensive applications in photoelectronics.Porphyrin is an important component of heme proteins, also has been widely applied in electrochemistry fields. Inspired by these mentioned above, it is proposed that MWCNTs and porphyrin have the potential for improving HRP activity. All the relative experiments and results are summarized as follows.4,4’-Hexafluorosio-propylidenediphthalic anhydride (6FDA) and oxydianiline (ODA) were used to synthesize a soluble polyimide (PI). It was blended with or without multiwalled carbon nanotubes (MWCNTs) and then electrospun into nanofibers on which HRP was immobilized by adsorption. The activity of immobilized HRP increases and then decreases as the MWCNTs mass increases in the nanofibers. The retention activity of immobilized HRP increases from2.38%to12.50%when MWCNTs mass is5wt%in the nanofibers. UV-vis analysis indicates that MWCNTs increases the activity of HRP via improving the transform of the catalytic intermediate "HRP I" to HRP.5,10-Bis(4-aminophenyl)-15,20-diphenylporphyrin (cis-D ATPP) was synthesized as the comonomer of polyimide. Porphyrinated polyimide (PPI) was obtained with a weight-average molarcular weight of at least1.0×106and a high porphyrin quantity in the polymer backbone. PPI was blended with or without MWCNTs and then electrospun into MWCNTs/PPI composite nanofibers on which HRP was also immobilized by adsorption. The activity of immobilized HRP first increases and then decreases as the porphyrin mass increases in PPI. The retention activity of immobilized HRP increases from2.38%to28.85%when the porphyrin mass is10.87mol%in PPI. Porphyrin is more conducive to promoting the activity than MWCNTs for the interaction between porphyrin and "HRP I" from the analysis of UV-vis spectrometry and fluorescence spectrometry. The highest retention activity of immobilized HRP is39.98%for the combination of porphyrin and MWCNTs.This research focused on the effects of MWCNTs and porphyrin to HRP activity and corresponding mechanisms, which would be important for the application research of HRP.