Abstract: A new 2×5 type of piezoelectric insulin-C peptide micro-array immunosensor was developed for the determination of insulin and C peptide. The energy converters were 10 MHz AT-cut quartz crystals with gold-coated electrodes. The monoclonal antibodies of insulin and C peptide were immobilized onto the surfaces of crystals gold electrodes respectively, then piezoelectric insulin-C peptide micro-array immunosensor was constructed by 2×5 type of immobilization clamping apparatus. The effects of methods, work concentrations, the amount and coherence of immobilization of antibody and the response parameters of the micro-array immunosensor such as temperature, time-cost and specificity etc. were investigated. Under the optimized conditions, the experimental results showed piezoelectric immunosensor had good response to insulin and C peptide whose frequency shifts were linearly dependent on insulin concentration in the range of 2.5—160.0 mIU/L and C peptide concentration in the range of 0.375—12.0 ng/mL. The piezoelectric micro-array immunosensor were used to detect insulin and C peptide in serum, the analytical results given by this approach were in satisfactory agreement with those given by radiometric immunoassay(P>0 05), with correlation coefficients 0 92 and 0 94. The piezoelectric micro-array immunosensor for the determination of insulin and C peptide is of high sensitivity, high specificity, low density micro-array structure, high analysis speed, unnecessary labelling, simple operation, real-time detection and repeated use, etc.. It is suitable for detecting insulin and C peptide of serum in clinical laboratory.

Key words: Piezoelectric immunosensor, Micro-array, Insulin, C peptide