Abstract: In this paper, the preparation of silk fibroin and the ways of immobilizing antibody on silk fibroin are investigated for electrochemical immunosensor. Cross-linking after hydrochloric acid activation, diazo, azide and cross-linking after hydroxylamine activation method are tested for immobilization. In comparison of diazo and azide me thods, the best reponse is obtained when the silk fibroin is activated by hydrochloric acid. The silk fibroin immunosensor is sensitive when measuring α -fetoprotein and the detection limit of 5 μg/L is found. It showes linear response over the concentration range of 10~300 μg/L with correlation coefficient 0 9996. When it is applied to clinical sample analysis, the results are satisfactory.

Key words: α-fetoprotein, immunosensor, immobilization, silk fibroin