Thermal stability of the immobilization process of horseradish peroxidase in electrospun polymeric nanofibers

The horseradish peroxidase enzyme (type VI 250 U mg^?1) was encapsulated in polymeric nanofibers using the electrospinning technique and successfully immobilized by the exposure to glutaraldehyde (GA) vapor in order to create covalent bonds between the polyivinilalcohol (PVA) polymeric chains and the enzyme molecules. The morphology of the nanofibers was analyzed by scanning electron microscopy (SEM) showing a diameter in the range of 100–200 nm. The presence of the enzyme in the electrospun nanofibers was confirmed by infrared spectroscopy (FTIR). The optimum crosslinking time was 1 h of exposure to GA vapor. The maximum percentage of the retained protein and the enzyme activity was obtained using the lowest initial enzyme concentration. The enzyme activity of the sample was retained after four reuse cycles. Differential scanning calorimetry (DSC) was used to study the thermal stability of the samples. The thermal study of the immobilized HRP enzyme provide for the first time additional information regarding the interaction of the HRP enzyme molecules with the PVA chains of the nanofiber matrix, as well as the effect of the crosslinking time in the glass transition temperature and the heat of fusion of the samples. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44811.