Preparation and characterization of artificial antigens for cadmium and lead

Cadmium and lead were conjugated to two carrier proteins using a bifunctional chelator [2-(4-aminobenzyl)-diethylenetriaminepentaacetic acid] to synthesize artificial antigens for cadmium and lead. The techniques, including ultraviolet spectrometry, circular dichroism, sodium dodecyl sulfate polyacrylamide gel electrophoresis, and inductively coupled plasma optical emission spectroscopy, were utilized for characterizing the artificial antigens. The results of ultraviolet spectrometry showed characteristic absorption peak shifts between conjugates and carrier proteins. Circular dichroism resulted that the second structure of the conjugates was α-helix. The sodium dodecyl sulfate polyacrylamide gel electrophoresis results revealed the differences of band migration and molecular weight among antigens, chelator protein conjugate, and carrier proteins. The result of coupling ratios revealed that the metal content of the antigens was much higher than that of carrier proteins. These results indicated that the artificial antigens of cadmium and lead were synthesized successfully and had potential application in immunoassays of cadmium and lead ions.