Abstract: Ahighly sensitive piezoelectric immunosensor has been developed for the detection of factor B. The sensor consists of an 9MHz piezoelectric crystal with an antibody on its gold electrodes surface that selectively interacts with the relative antigen. The method of immobilization of the antibody protein with polyethyleneimine adhesion and glutaraldehyde crosslinking was employed. The immobilization methods gave the good results in terms of sensitivity, stability and reproducibility. The influence factors related to the sensitivity of the system such as the titer of antibody, the reaction time of immunoreaction etc., were discussed. Under the optimized experimental conditions chosen, the coated crystal had a good response to Factor Bin the mass concentration range of 10^-5-10^-3g/L. This sensor had a good selectivity, other materials in human serum did not interfere the detection remarkably. The recovery of sensor system is about 82%. The crystal could be regenerated by desorption of the bound antigenwith 0.2 mol/Lethanolamine(pH=8). The sensor could be reused nearly 6 times without detectable loss of activity.

Key words: Piezoelectric immunosensor, Factor B, Immobilization of antibody