Figure 5.

Molecular interactions at the surface of the biosensor biochip. Schematic illustrating the functionalisation of the gold-coated biochip with firstly anti-IgG antibodies (red), and secondly with anti-MMP-8 capture antibodies (blue), followed by detection by successive addition of sample (containing MMP-8) and anti-MMP-8 detection antibody (green). The binding of the anti-MMP-8 detection antibody to MMP-8 bound to the immobilised complex results in a perturbation of mass at the biochip surface sufficient to generate a phase change (Δφ) in the surface acoustic wave detected by the biosensor control box. In later experiments, the anti-MMP-8 capture antibody was bound directly to the biochip, omitting the anti-IgG antibody step. A full description of the prototype biosensor structure, microelectronics and detection system has been recently published²⁸.