ABSTRACT
Optical immunosensors utilise properties of light, such as refraction, production of evanescent waves and reflection. This chapter looks at the different facets of optical signalling technology and its use in immunoassays. The uses of label-free optical monitoring systems have increased in popularity due to an associated ‘ease-of-construction’, low cost, and superior performance in complex matrices while maintaining high sensitivities. Incident light is shone between two media of different optical densities. Optical waveguide lightmode spectroscopy is an alternative optical sensor platform that utilises waveguide technology. Ellipsometry is an additional optical detection technique that recognises changes in the thickness of ultrathin films. Surface plasmon resonance (SPR) is an optical signal transduction system that is commonly used to determine the binding of antibody/antigen partners. SPR-based sensors employ several different methods for optical excitation of surface plasmons. The functionalised nanorods were shown to possess unique magnetic properties, exceptional optical properties and good biocompatibility, which can be used as an immobilisation matrix for biomolecules.
