On-chip photonic label-free biosensors

On March 30th  at 2.00 p.m., in room A107 Polo Scientifico e Tecnologico Fabio Ferrari,  Davide Gandolfi will present his thesis “On-chip photonic label-free biosensors”

The development of a highly integrated optical biosensor is expected to significantly impact on the performances and on the throughput of biochemical assays, with applications in the field of pharmaceutical research, point-of-care diagnostic, food-borne pathogens screening and safety.

In this dissertation, we will describe the design and the realization of two types of multiplexed silicon-based photonic sensor, operating at wavelength of 850 nm. The first is based on the whispering-gallery-modes of a microring resonator, while the second is based on a spectrally resolved asymmetric Mach-Zehnder.

The experimental characterization assessed the high resolution of the devices, which are able to resolve variations in refractive index with a limit of detection down to 10^-6 refractive index units (RIU).

The specific aptamer-based bioassay of Aflatoxin-M1 molecules is also evaluated, proving specific detection limits down to about 100 pg/ml and re-usability of the chip for up to nine times.

This work has been funded by the FP7 European Project Symphony (grant number 610580).