Detection of somatropin and corticosterone with imaging ellipsometry

Imaging ellipsometry has been recently developed to visualize the lateral thickness distribution of biomolecular layers with a high sensitivity for a thickness variation, i.e., the visualization of molecular interaction on biolayer with a measurement of thickness variation. By using this technique, we have made the detection of protein hormone, human somatropin (HGH) and steroid hormone, corticosterone: BSA. In the study, silicon wafers were used as substrates on which the anti-HGH or anti-corticosterone was adsorbed to make a biochip, and then the biochip was incubated in solutions containing HGH or corticosterone: BSA for molecular interaction. Thus, the hormones could be detected by the thickness increase, which caused by the specific affinity between hormones and their anti-bodies. In present study we can detect HGH in concentrations of 0.08, 0.008 and 0.004 IU/ml and corticosterone:BSA in concentrations even till 0.5 /spl mu/g/ml and 0.05 /spl mu/g/ml.