In order to study the effects of external electrostatic field of electret on structure and dielectric property of procine insulin

and to provide theory evidence for the study of the electret to increase the effect of insulin on blood glucose reducing

the corona charged 500 V

1 000 V

and 1 500 V polypropylene（PP） electrets were acted on insulin as electric field source. The 1H-NMR spectroscopy

gel electrophoresis

and piezoelectric d33 coefficient were determined

respectively. The results show that: 1) PP electret with different surface potential can produce stable electrostatic field on both sides of the insulin solution or insulin patch. The higher the surface potential of the electret is

the stronger the electrostatic field would be. 2) The external electrostatic field of PP electret has no obvious effects on the primary and secondary structures of insulin. 3) The piezoelectric d33 coefficients for insulin patches treated by 500 V

1 000 V

and 1 500 V PP electrets are 15.7

21.3

and 32.0 folds more than those of the non-electret treated insulin patch. 4) The 1H-NMR spectroscopy indicates that the hydrogen network of insulin structure is changed after the action of electret. So

electrostatic field produced by PP electret leads to the weak polarization of the insulin molecules

alters the charging characteristic of the insulin

and it is helpful for the formation of insulin monomers. Therefore

electrets can increase the effect of insulin on blood glucose reducing.