An Insulin Molecularly Imprinted Electrochemical Sensor Based on Epitope Imprinting

A new molecularly imprinted electrochemical sensor for direct detection of insulin was prepared based on epitope imprinting. The molecularly imprinted polymer was fabricated by electropolymerization with C-terminal polypeptide of insulin self-assembled on the Au electrode as template molecule and o-PD as functional monomer. After elution of template molecules by NaOH solution, the imprinting cavities were formed with the three-dimensional structure matching with the C-terminal polypeptide of insulin molecule. The imprinting cavities could specifically recognize and rebind with insulin molecules. With K-3[Fe(CN)(6)]/K-4[Fe(CN)(6)] as a probe, the insulin could be indirectly detected. There was a linear relationship between the response current and the concentration of insulin in the range of 1.0 x 10(-14). 5.0 x 10(-13) M, and the detection limit was 7.24 x 10(-15) M (3 sigma/S). The developed sensor exhibited good selectivity and stability; and was successfully applied to determination of insulin in serum samples with satisfactory results.