We have previously studied the adsorption of anti-beta-hCG at the hydrophilic silicon oxide/water interface and the subsequent binding by antigen hCG. We propose to extend this work to the study of antibody adsorption onto hydrophobic and aminated surfaces. The objective of this work is to establish how surface chemistry (hydrophobicity and charge type) and the adsorbed layer packing density affect the conformational orientation of the antiboty and its hCG binding efficiency.