聚苯胺纳米纤维固定化辣根过氧化物酶的合成及性能研究

Immobilization of Horseradish Peroxidase on Polyaniline Nanofibers

FeCl3为氧化剂合成了聚苯胺纳米纤维，纤维直径20～30nm，并以此为载体对辣根过氧化物酶进行了固定化．SEM，FTIR，UV—Vis等结构表征证明辣根过氧化物酶HRP中的质子可作为掺杂剂与聚苯胺主链中的氮结合，酸根离子作为对阴离子依附于聚苯胺主链周围，实现了聚苯胺载体对生物酶的固定化．聚苯胺纳米纤维具有较大的比表面积，有利于增加酶的负载量，提高固定化酶活性．该方法简单，快速，载体材料无需活化．与游离酶相比，固定化酶对pH，高温的耐受性，不同温度下的热稳定性均有了明显的提高，在4℃条件下保存7周后固定化酶活性几乎没有损失，重复使用6次后仍可保持80％的酶活，说明纳米结构的聚苯胺是一种良好的载体，可实现生物酶的高效固定化．

PANI nanofibers oxidized by FeCI3 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 ixg/mgPANI for undoped-PANI,90 p,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.