Historical overview and introduction to biological problems

1801

Thomas Young observed that two slits placed in front of a light source created a pattern of intensity fringes on a screen. This phenomenon is the basis of modern interferometers, which have now been adapted to measure ligand–receptor interactions.

1902

R. W. Wood observed for the first time the phenomenon of surface plasmon resonance (SPR), which provided a simple and direct sensing technique for probing refractive index changes that occur in the very close vicinity of a thin metal film surface.

1968

E. Kretschmann and H. Z. Raether proposed the basic configuration of an SPR sensor, with an optical system containing a prism coupled to a reaction cell.

1982–1983

B. Liedberg and colleagues realised the potential of SPR for macromolecular binding studies since the change in refractive index is dependent on the molecules accumulating at the metal surface. They adsorbed an antibody specific to immunoglobulin G onto a gold sensing film, resulting in the selective binding and detection of the protein.

1980s, 1990s

Several biosensors, based on either interferometry or SPR, that allowed the simple, rapid and non-labelled assay of various biochemical analytes such as proteins, DNA and small compounds, became commercially available.

1993

The potential to analyse weak affinities by SPR instrumentation was demonstrated by S. Davis and coworkers in their studies of cell surface receptor interactions.

2000 and after

Optical arrays were developed to analyse the interactions of thousands of different molecules simultaneously, with high selectivity and sensitivity.