  In the biochemical sensing field, a fervent research activity related to the
development of real time, low cost, compact and high throughput devices for the
detection and characterization of natural or synthetic nanoparticles NPs
actually exists. In this research scenario, different platforms for biosensing
purposes have been developed according to the huge amount of physical effects
involved in the transduction of the biochemical-signal into a measurable output
signal. In the present work two different optical platforms for NP detection
have been investigated, one based on integrated optics and the other based on
microscopy. Both the approaches rely on the study of the interaction of an
electromagnetic wave with a small particle in the hypothesis of dealing with a
Rayleigh scatterer, i.e. a nanoparticle having a size really smaller than the
one of the wavelength of the incident light and scattering light elastically.
